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EEB263 > Final Exam > Flashcards

Final Exam Flashcards

1
Q

Sagittal

A

Section of the body that is vertical and lengthwise to the body, dividing it into right and left parts
- Can be sagittal/midsagittal or parasagittal

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2
Q

Midsagittal

A

Sagittal section directly through the midline, dividing the body into equal halves

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3
Q

Parasagittal

A

Sagittal section parallel to the midline, dividing the body into unequal left and right sections

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4
Q

Transverse

A

Section of the body that is vertical and perpendicular to the length of the body, dividing it into front and back parts
- Perpendicular to the sagittal section

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5
Q

Frontal (section)

A

Section of the body that is horizontal and lengthwise to the body, dividing it into top and bottom parts
- Perpendicular to both sagittal and transverse planes

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6
Q

Anterior

A

Towards the head

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7
Q

Posterior

A

Towards the tail

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8
Q

Dorsal

A

Towards the back

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9
Q

Ventral

A

Towards the belly/substrate

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10
Q

Medial

A

Towards the sagittal midline

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11
Q

Lateral

A

Away from the sagittal midline

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12
Q

Proximal

A

Closer to the point of reference

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13
Q

Distal

A

Farther from the point of reference

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14
Q

Craniata

A

Largest clade within Chordata and is the clade to which the vertebrates belong

  • Related to other chordates, like Urochordata and Cephalochordata
  • More distantly related to Hemichordata
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15
Q

Pharyngotremata

A

Clade formed of the chordates and hemichordates

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16
Q

Chordata

A

Clade that contains the craniates, urochordates and cephalochordates

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17
Q

Protochordates

A

Group that includes everything EXCEPT the chordates

  • i.e. hemichordates
  • Not a natural grouping
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18
Q

Important Chordate Characters

A
  1. Pharyngeal slits
  2. Notochord
  3. Dorsal hollow nerve cord
  4. Endostyle
  5. Post-anal tail
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19
Q

Notochord

A

Axial structure in chordates that stiffens the midline and is flexible but resistant to compression

  • Precursor to the spine
  • Filled with fluid and surrounded by collagenous and connective tissue sheaths
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20
Q

Hemichordata

A

Sister group to Chordata
Two clades
- Enteropneusta
- Pterobranchia

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21
Q

Pterobranchia

A

Clade within the Hemichordata

  • Filter-feeder or suspension feeder
  • To feed, secretes a sticky fluid onto a proboscis that projects just beyond the proboscis/mouth
  • Lopophores (tentacles) help move food to mouth
  • Live in tube-like structures when living in colonies

Lacks chordate characters:

  • No post-anal tail
  • No pharyngeal slits (most of the time)
  • No dorsal hollow nerve cord
  • No endostyle (most of the time)
  • No notochord
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22
Q

Enteropneusta

A

Acorn worms
Clade within the Hemichordata
- Filter feeder that waits for prey to fall into its burrow
- Has many pharyngeal slits (used for water expulsion)
- Has dorsal nerve cord

Lacks chordate characters:

  • No post-anal tail
  • No endostyle
  • No notochord
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23
Q

Endostyle

A

Mid-ventral groove that secretes mucus

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24
Q

Urochordata

A

Tunicates
Clade within Chordata
- Has a large, barrel-shaped pharynx with many pharyngeal slits
- Has an endostyle

Characters in the juvenile

  • Post-anal tail with a notochord and dorsal nerve cord
  • Endostyle and pharyngeal slits, found in adult, are both present as well
  • All five chordate characteristics ONLY present in the juvenile
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25
Q

Cephalochordata

A

Branchiostoma/amphioxus
Clade within Chordata, most closely related to craniates
- Have all typical chordate characters
- Notochord extends into the head
- Pharyngeal slits empty into a common chamber
- Filter feeders that sit buried in the substrate except for their head
- Poor swimmers despite fish-like body (lack paired fins)
- Muscular bundles segmented along the body wall
- Has no true brain and poorly developed sense organs

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26
Q

Heterochrony

A

A relative change in developmental timing that leads to changes in size and/or shape

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27
Q

Paedomorphosis

A

The retention of juvenile features in the adult of a descendent

  • Adult retains characters present in the young of the ancestral stage
  • Can do this in many ways: slow somatic development, speed up sexual development

Implication for vertebrates:

  • The larval stage of urochordates have all chordate characteristics
  • Higher chordates may have developed from an ancestor that initially resembled the larval urochordate
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28
Q

Craniata

A

Clade within Chordata

- Refers to chordates that have a well-defined “head” and a hard skull

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29
Q

Agnathans

A

Craniates that lack jaws

  • Also lack paired appendages
  • Only extant species are the cyclostomes, used to also include ostracoderms
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30
Q

Ostracoderms

A

Extinct, armoured agnathans

  • Covered by bony plates
  • Jawless
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31
Q

Cyclostomes

A

Agnathans that include the Petromyzontoidea and Myxinoidea

  • Parasitic, rasping tongue allows them to burrow into prey
  • Entirely cartilaginous skeleton
  • Single median nostril
  • No true teeth - keratinous “teeth” known as denticles
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32
Q

Petromyzontoidea

A

Lampreys

  • Predatory, parasitic
  • Oral cup attaches to prey, allowing them to drink blood and other body fluids
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33
Q

Myxinoidea

A

Hagfish

  • Scavengers
  • Use horny tongue to rasp flesh from dead or dying prey
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34
Q

Denticles

A

The keratinous teeth of cyclostomes

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35
Q

Gnathostomata

A

True, jawed fishes

- Includes the placoderms and eugnathostomes

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36
Q

Placodermi

A

Extinct gnathostomes

  • Usually have lots of bony armour
  • Have jaw-like structures, but these are made from their armour (dermal bone) rather than branchial arches (visceral bone/cartilage)
  • Paired fins
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37
Q

Eugnathostomata

A

“True jawed vertebrates”
- Jaw made from visceral structures, either bone or cartilage

Two major groups:

  • Chondrichthyes
  • Teleostomi
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38
Q

Chondrichthyes

A 
Sharks and relatives
Basal eugnathostomes
- Cartilaginous skeleton with very few bits of bone (secondary loss)
- Well-developed, paired fins
- Two nostrils
- Males usually have a clasper

Two main clades:

  • Elasmobranchii
  • Holocephalia
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39
Q

Elasmobranchii

A

Sharks, skates and rays

  • More diverse than their sister group, the holocephalians
  • Upper jaw is movable since it is free from the braincase
  • Gills open directly to the environment
  • Rapid tooth replacement
  • Most species have an elongated, fusiform body
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40
Q

Holocephalia

A

Chimaeras and ratfish

  • Much less diverse than their sister group
  • Slow tooth replacement
  • Pharyngeal slits are covered by an operculum (flap of skin)
  • Upper jaw is usually fused to the braincase
  • Tend to be benthic mollusc feeders, so teeth are flattened to be used in grinding
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41
Q

Stages leading to the typical vertebrate condition

A
  1. Prevertebrate stage
  2. Agnathan stage
  3. Gnathostome stage
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42
Q

Prevertebrate Stage

A

Urochordates, cephalochordates

  • Suspension feeders (cilia-mucus)
  • Small, poor swimmers
  • Ciliary action produces movement of water
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43
Q

Agnathan Stage

A

Agnathans (durrr)

  • Muscular bands plus cartilaginous bars in the pharynx produce a muscular pump to move water for feeding
  • Still a filter feeder, but on larger particles due to larger size
  • Absence of paired fins make them poor swimmers
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44
Q

Gnathostome Stage

A

Jawed vertebrates

  • Development of jaws allows selection of larger prey and hunting
  • Larger prey allows for larger size
  • Problem of how to achieve gas exchange solves through addition of gills to pharyngeal slits
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45
Q

Higher Fishes

A

Term that is usually used to refer to Osteichthyes

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46
Q

Osteichthyes

A

“Bony fishes”

  • Bony skeleton is retained and enhanced
  • Most successful vertebrates in terms of diversity and numbers

Groups:

  • Actinopterygii
  • Sarcopterygii
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47
Q

Teleostomi

A

Clade that includes Acanthodii and Osteichthyes

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48
Q

Acanthodii

A 
Known as "spiny sharks" (not sharks)
Extinct
- Heterocercal tail
- Bony plates as well as scales
- Have characteristically strange paired fins that are supported by a spine; more than two pairs
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49
Q

Actinopterygii

A

Ray-finned fishes

  • Most successful of the bony fishes (99% of extant species)
  • Inhabit all marine and freshwater habitats
  • Fins supported by rays, so have little muscular development
  • Primitively had one dorsal fin and ganoid scales
  • Isolated nasal sacs with no internal nostril

Three types

  • Chondrostei
  • Holostei
  • Teleostei
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50
Q

Sarcopterygii

A

Lobe-finned/Fleshy-finned fishes

  • Few extant species, but used to be more successful
  • Ancestors of terrestrial vertebrates… so all tetrapods are sarcopterygians
  • Fins have well-developed skeletal support and strong muscular development
  • Have cosmoid scales and two dorsal fins
  • Nasal opening extends into the oral cavity
  • Diphycercal tail

Extant species

  • Dipnoi
  • Coelecanth
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51
Q

Dipnoi

A

Lungfishes

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52
Q

Coelecanth

A

“Latimeria”

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53
Q

Chondrostei

A

Early, primitive actinopterygians

  • Few extant species, inc. sturgeons
  • Hyomandibular slopes backward
  • Long jaw
  • Maxilla involved in biting
  • Heterocercal tail
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54
Q

Holostei

A 
Not a natural group
Intermediate actinopterygians
- Freshwater species that are typically fast-swimming
- Jaws shortened
- Hyomandibular more or less vertical
- Premaxilla & maxilla tightly fused
- Premaxilla elongated
- Reduced heterocercal tail, more symmetry
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55
Q

Teleostei

A

Most living fishes

  • Great diversity in body shape and activity
  • Hyomandibular slopes forward
  • Premaxilla expands to free the maxilla and exclude it from biting
  • Maxilla allows premaxilla to slide back and forth
  • Jaws can be protruded when mouth opened, allowing for greater control and different kinds of biting
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56
Q

Trends in Actinopterygian Body shape and fin form

A

Early

  • Fusiform body shape
  • Fast-swimming
  • Fins positioned for optimal gliding

Advanced

  • Body more shortened
  • Pectoral fins move dorsally, to be used as brakes and allow for greater control
  • Pectoral fins move anteriorly
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57
Q

Heterocercal

A

Tail in which the posterior end of the body curves upward so that there are more fin rays ventrally on the tail

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58
Q

Homocercal

A

Caudal fin is symmetrical superficially, but internally the vertebrae still curve dorsally

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59
Q

Diphycercal

A

Tail type in which the caudal fin is symmetrical both superficially and internally

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60
Q

Tetrapoda

A

Vertebrates whose ancestors made the transition to terrestrial life

  • Breathe air
  • Are mainly amphibious or terrestrial, although some specialized descendants returned to the water

Two main groups

  • Amphibia
  • Amniota
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61
Q

Stegocephalia

A

Group that includes the tetrapods and their non-terrestrial, but still limbed, ancestors

  • Fully-formed limbs, skull and vertebrae able to support weight on land
  • Basal species include Icthyostega and Acanthostega, which were not well-adapted to life on land
  • Still retain branchial arches and gills, so were most likely aquatic
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62
Q

Elpistostegids

A

Sarcopterygians that have made some changes to be similar to tetrapods but are still clearly fish

  • Have internal nostrils
  • Includes Tiktaalik, who is closely related to stegocephalians
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63
Q

Amphibia

A

Biologically intermediate between fishes and more derived tetrapods
- In general, lay eggs in water and have an aquatic larval stage; this means they are restricted to a moist environment

Living group: Lissamphibia

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64
Q

Amniota

A

More derived tetrapods
- Lay amniotic eggs

Two major lineages

  • Reptilia
  • Synapsida
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65
Q

Amniotic Egg

A

Egg type in which extra-embryonic membranes surround and protect the developing embryo

  • Prevents desiccation
  • Engages in gas exchange
  • Results in a longer developmental period
  • Young emerge as essentially miniature adults, no metamorphosis
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66
Q

Lissamphibia

A

Extant amphibians

  • Some still retain ancient forms of locomotion, but are notably not primitive
  • Cutaneous respiration is the primary form of gas exchange

Three groups

  • Caudata (salamanders)
  • Anura (frogs)
  • Gymnophiona (caecilians)
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67
Q

Anapsid

A

Skull type in which there are no temporal fenestrae

  • Typically present in basal amniotes, but debate over if its an ancestral form
  • Still retained in turtles
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68
Q

Euryapsid

A

Skull type in which there is a single temporal fenestra (supratemporal)
- Seems to be descended from diapsid skull through secondary closure of the infraorbital fenestra

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69
Q

Diapsid

A

Skull type in which there are two temporal fenestrae

- Most common form

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70
Q

Synapsid

A

Skull type in which there is a single temporal fenestra (infratemporal)

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71
Q

Reptilia

A

Diverse lineage of tetrapods including lizards, birds, dinosaurs, etc.

Two main groups

  • Parareptilia
  • Diapsida
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72
Q

Parareptilia

A

Reptiles with anapsid skulls

- Inc. Testudines

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73
Q

Testudines

A

Turtles

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74
Q

Diapsida

A

Large, diverse group of reptiles

  • Diapsid and euryapsid skull
  • Diverse even by standards of all of Tetrapoda

Two main groups

  • Archosauromorphia
  • Lepidosauromorphia
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75
Q

Archosauromorphia

A

Includes:

  • Crocodiles
  • Pterosaurs
  • Dinosaurs (inc. birds)
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76
Q

Lepidosauromorphia

A

Includes:

  • Ichthyosaurs
  • Plesiosaurs
  • Rhynchocephalians
  • Lizards (inc. snakes)
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77
Q

Synapsida

A

One of the major clades within Amniota

  • Includes Mammalia and their fossil relatives
  • Characterized by synapsid skull type

Two broad groups

  • Pelycosaurs
  • Therapsida
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78
Q

Pelycosaurs

A

Early, basal group of synapsids

- Not a natural group

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79
Q

Therpasida

A

More derived group of synapsids

  • Includes mammals
  • Some early species had intermediate leg positioning, with hind limbs under body but forelimbs swung out to the side
  • Several groups in addition to mammals, including symmetrodonts, multituberculates and triconodonts
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80
Q

Mammal-like Reptiles

A

Term used to refer to all non-mammalian synapsids

  • Reflects the idea that they were more reptile-like in their general way of living
  • Transitional stages towards mammalian condition have all four bones (squamosal, quadrate, articular, dentary) involved in jaw bones
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81
Q

Mammalia

A

Group of therapsids that represents all mammals

Characterized by:

  • Mammary glands
  • Hair
  • Muscular diaphragm
  • External ears (a few exceptions)
  • Mandibular halves formed by single dentary
  • Squamosal/dentary jaw joint
  • Three middle ear ossicles: malleus, incus, stapes
  • Teeth tend to be complex with precise occlusion
  • Body held upright instead of sprawling

Two groups

  • Monotremata
  • Theria (inc. Marsupialia & Eutheria)
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82
Q

Relation between ear ossicles and jaw joint in mammals vs. reptiles

A

The two additional ossicles in mammals are derived from the mandibular bones in reptiles

  • Articular = malleus
  • Quadrate = incus
  • Stapes = stapes

In addition, the angular in the reptilian jaw forms the ectotympanic in mammals

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83
Q

Tribosphenic Molar

A

Form of molars where the upper molars have three cusps and the lower molars have four

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84
Q

Bunodont Molar

A

Form of molars where both the upper and lower teeth have four cusps

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85
Q

Monotremata

A

Group of mammals that includes only three extant species

  • Platypus (Ornithorhynchidae) & 2 sp. of echidna (Tachyglossidae)
  • Have hair, suckle young and are endothermic

Ancestral features

  • Cloaca
  • Absence of nipples
  • Lay eggs in a leathery shell
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86
Q

Marsupialia

A

A.K.A. Metatheria

  • Much more diverse group than monotremes, but less so than placental mammals
  • Found in Australia and South America (as well as their surrounding regions)
  • Females of many species have a pouch in which they carry their young
  • Young are usually born at an early stage and complete their development in their mother’s pouch
  • Have a placenta, but it is a yolk sac placenta and is not vascularized except in peramelids
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87
Q

Eutheria

A

A.K.A. placental mammals

  • Much more numerous, diverse and widespread than marsupials and monotremes
  • All species have a chorioallantoic placenta
  • Young remain in utero until they are developmentally more advanced before being born
  • Occupy many niches, including the air, water and land
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88
Q

Chorioallantoic Placenta

A

Type of placenta that is vascularized

  • Found in peramelids and eutherians
  • Comes at a price: can’t dispose of offspring that are too energetically costly
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89
Q

Embryology

A

The processes involved in early development of a fetus

  • Important process for the animal
  • Characters can be used to study phylogenetic relationships
  • Understanding helps us make sense of the organization of various systems
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90
Q

Early embryological processes

A

Vary greatly among vertebrates but can be generally simplified into three or four patterns

  • All lead to more or less the same end: gastrula with similarly arranged primary body tissues
  • Further differentiation can be more easily compared
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91
Q

Microlecithal

A

Egg type in which there is little yolk

  • E.g. in amphioxus
  • Blastula is one cell thick
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92
Q

Mesolecithal

A

Egg type in which there is a moderate amount of yolk

  • Initial divisions less equal than in microlecithal egg
  • Cell of the animal pole are smaller than in microlecithal
  • Blastula is several cells thick
  • Blastocoele is displaced towards the animal pole
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93
Q

Macrolecithal

A

Egg type in which there is a lot of yolk

  • Essentially a big mass of yolk with a small amount of protoplasm on top
  • Only small cap of protoplasm divides, so it is difficult to compare to division in other egg types
  • Blastula is a plate of cells at the animal pole that is separated from the yolk by the blastocoele
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94
Q

Yolk

A

Food material that is inert to an egg

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95
Q

Vegetal Pole

A

End of an egg towards which the yolk gravitates

- Lower hemisphere of the egg

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96
Q

Animal Pole

A

End of an egg that is less yolky

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97
Q

Early divisions of an egg cell

A

Occurs in the protoplasm of an egg

  1. Vertical
  2. Vertical
  3. Horizontal
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98
Q

Blastula

A

Spherical form of an egg after continued divisions of the protoplasm
- Actually a plate of cells in macrolecithal eggs

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99
Q

Blastocoele

A

Central cavity found within a blastula

- Separates blastula from yolk in macrolecithal eggs

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100
Q

Mammalian Embryo Development

A

Different from egg forms, since the embryo develops in the uterus

  • Spherical mass is formed like in microlecithal eggs but the resemblance is only superficial
  • Becomes a trophoblast with an inner cell mass
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101
Q

Trophoblast

A

Spherical mass of cells that forms in mammals after the continued division of the protoplasm
- Has an inner cell mass toward the animal pole

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102
Q

Inner Cell Mass

A

Cluster of cells towards the animal pole within a trophoblast
- Later forms the embryo and the extra-embryonic membranes

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103
Q

Primary Germ Layers

A

Basic arrangement of the body

  • Become delimited during gastrulation then become differentiated into various body regions
  • End up producing all the major body organs
  • Each layer produces the same structures in adult vertebrate bodies, with few exceptions

Three layers

  1. Ectoderm
  2. Mesoderm
  3. Endoderm
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104
Q

Gastrula

A

Forms through continued cell division, migration and differentiation in the blastula

  • Vegetal pole folds into a cup-like structure, mainly by the rolling of cells into the blastocoele
  • Cells of the animal pole form the outer layer while the vegetal pole forms the lining of the gut
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105
Q

Gastrocoele

A

A.K.A. Archenteron
Central cavity within a gastrula
- Formed from pocketing of of the blastula as it forms the gastrula

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106
Q

Blastopore

A

Entrance into the gastrocoele

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107
Q

Ectoderm

A

Germ layer formed from the animal pole of an egg
- Becomes the skin and nervous system

Also includes: neurectoderm

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108
Q

Mesoderm

A

Germ layer between the ectoderm and endoderm
- Becomes the somatic skeleton, muscle and circulatory system

Two kinds

  • Chordamesoderm
  • Lateral mesoderm
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109
Q

Endoderm

A

Germ layer formed from the vegetal pole of an egg

- Becomes the digestive tract, visceral muscles and visceral skeleton

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110
Q

Neurectoderm

A

Forms from the dorsal middle of the ectoderm

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111
Q

Chordamesoderm

A

Portion of the mesoderm that becomes the notochord

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112
Q

Lateral Mesoderm

A

Portion of the mesoderm that forms pretty much everything but the notochord

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113
Q

Development of the Ectoderm

A
  1. Partially differentiates into the neurectoderm dorsally
  2. Neurectoderm inpockets and ectoderm expands to cover it
  3. Neural crest cells and neurogenic placodes form
  4. Ectoderm covers the neural tube
  5. Neural crest cells begin to migrate
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114
Q

Development of the Mesoderm

A
  1. Differentiates into the chordamesoderm and lateral mesoderm
  2. Mesoderm becomes segmented into somites and expands laterodistally
  3. Lateral mesoderm subdivides, forming the coelom
  4. Completely comes between the ectoderm and endoderm
  5. Lateral mesoderm subdivides into the epimere, mesomere and hypomere as the coelom enlarges
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115
Q

Development of the Endoderm

A
  1. Expands dorsomedially
  2. Completely surrounds the gastrocoele
  3. Becomes relatively smaller
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116
Q

Neural Crest Cells

A

**In notes

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117
Q

Neurogenic Placodes

A

**In notes

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118
Q

Epimere

A

Dorsal subdivision of the lateral mesoderm

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119
Q

Mesomere

A

A.K.A. nephrotome
Middle subdivision of the lateral mesoderm
- Becomes the kidney, excretory ducts and reproductive ducts

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120
Q

Hypomere

A

Ventral subdivision of the lateral mesoderm

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121
Q

Development of the Epimere

A
  1. Subdivides lateromedially into the dermatome, myotome and sclerotome
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122
Q

Dermatome

A

Lateral subdivision of the epimere

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123
Q

Myotome

A

Middle subdivision of the epimere

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124
Q

Sclerotome

A

Medial subdivision of the epimere

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125
Q

Development of the Hypomere

A
  1. Coelom expands further
  2. Expands dorsomedially to enclose the endoderm
  3. Subdivides into a somatic layer and a visceral layer
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126
Q

Development of the Dermatome

A
  1. Expands deep to the ectoderm

2. Loses segmentation

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127
Q

Development of the Myotome

A
  1. Expands dorsally between the ectoderm and sclerotome and ventrally between the ectoderm and hypomere
  2. Is subdivided by a horizontal skeletogenous septum
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128
Q

Development of the Sclerotome

A
  1. Surrounds the notochord and the neural tube
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129
Q

Structures formed from the Ectoderm

A
  • Epidermis and derivatives
  • Lens of the eye
  • Anterior lining of the oral cavity
  • Various sensory head structures (neurogenic placodes)
  • Visceral skeleton, including jaws
  • Meninges
  • Structures of the nervous system
  • Neural tube: brain, spinal cord, nerves
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130
Q

Structures formed from the Dermatome

A
  • Dermis of the integument
  • Dermal muscles
  • Dermal skeletal structures
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131
Q

Structures formed from the Myotome

A
  • Skeletal muscles: epaxial and hypaxial

- Appendicular skeleton

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132
Q

Structures formed from the Sclerotome

A

Vertebral column

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133
Q

Structures formed from the Visceral Hypomere

A
  • Visceral serosa, including mesenteries
  • Visceral musculature
  • Heart
  • Blood vessels
  • Lymph vessels
  • Gonads
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134
Q

Structures formed from the Somatic Hypomere

A

Parietal serosa

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135
Q

Structures formed from the Endoderm

A
  • Liver
  • Pancreas
  • Lining of the lungs
  • Digestive tract
  • Urinary bladder
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136
Q

Integument

A

A.K.A. Skin
Acts as the covering for the body and is one of the largest organs
- Protects the body from UV radiation, mechanical forces, micro-organismal invasion
- Acts as camouflage and colouring
- Regulates temperature
- Creates claws, hair, feathers, nails, horns, etc.
- Can be used for respiration
- Tends to become thicker as species become more derived, but many vertebrates still have (semi)permeable skin

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137
Q

Primary Body Tissues

A
  • Epithelial
  • Connective
  • Muscular
  • Nervous
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138
Q

Epithelial Tissue

A

Layer(s) of cells that forms a barrier

  • Covers exposed surfaces as part of the skin
  • Lines body cavities
  • Cells are tightly bound together
  • Usually avascular
  • Have few, if any, nervous structure
  • Has apical, exposed surface and a basal surface that attaches to the basement membrane that connects it to underlying body structures
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139
Q

Serosa

A

Epithelial tissue that is internal and has no exit

  • Thoracic: pleura
  • Abdominal: peritoneum
  • Blood vessels: endothelium
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140
Q

Mucosa

A

Epithelial tissue in structures that have an exit

  • Respiratory tract
  • Digestive tract
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141
Q

Epidermis

A

Superficial, epithelial layer of integument

  • Formed from the ectoderm
  • Usually thin
  • Avascular
  • Has almost no nervous structures

Two main layers (five total)

  • Stratum corneum
  • Stratum basale
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142
Q

Dermis

A

Deep, connective tissue layer of integument

  • Formed mainly from the dermatome
  • Usually relatively thick
  • Vascularized
  • Has nervous structures in the form of sensory receptors
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143
Q

Issues with (Semi)Permeable Skin

A

When away from water, the organism will lose internal water quickly
- Even marine vertebrates lose water because they are less than 50% seawater

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144
Q

“Water-Proofing” Skin

A

Change the nature of the epidermis so that the most superficial parts become differentiated into a layer of dead, hardened cells

  • Incorporates insoluble proteins like keratins
  • Skin considered cornified or horny
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145
Q

Hypodermis

A

A.K.A. Superficial fascia
Deep to the dermis
- Mainly loose connective tissue and adipose connective tissue

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146
Q

Stratum Corneum

A

Superficial layer of the epidermis formed from dead cells

  • Thin
  • Formed of dead flattened keratin-filled keratinocytes that have been pushed up from the stratum basale
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147
Q

Stratum Basale

A

A.K.A. Germinativum
Deep, living, layer of the epidermis that contains dividing cells
- Most cells are keratinocytes, which are constantly being formed there
- Keratinocytes pushed superficially as new ones form and take on keratins

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148
Q

Integument in Fishes

A

Skin is relatively thin

  • Epidermis has few keratinized cells, so is mostly living
  • Secretes mucus that helps protect against infectious bacteria, makes the fish slippery, helps reduce drag and contains various chemicals
  • Sometimes forms specialized keratinized structures, such as denticles in the lamprey
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149
Q

Integument in Derived Fishes

A

Scales usually present

  • Scales formed from the epidermis and dermis
  • May include enamel (epidermal), dentin (dermal) and bone (dermal)
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150
Q

Placoid Scales

A

Type of scale seen in sharks

  • Scale is formed from dentin and projects through the epidermis
  • Capped by enamel
  • No dermal bone
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151
Q

Dermal Bone in Fish

A
  • Forms the bony plates on the head and trunk in ostracoderms and placoderms
  • More posteriorly, bone is broken into smaller dermal scales; also present over actinopterygians and sarcopterygians
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152
Q

Bony Fish Scales

A

Formed by dermal bone and may be capped by enamel and dentin

Different Types

  • Cosmoid Scales (primitive sarcopterygians)
  • Ganoid Scales (primitive actinopterygians)
  • Teleost Scales (derived actinopterygians): Cycloid or Ctenoid
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153
Q

Integument in Amphibians

A

Tends to be thin and composed entirely of live cells

  • Stratum corneum is thin and provides minimal protection against mechanical abrasion and water loss
  • Scales are absent except in some caecilians
  • Cutaneous respiration is extremely important, so capillaries reach into the lower epidermis
  • Generally have mucus and poison glands
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154
Q

Integument in Reptiles

A

Skin that has more extensive keratinization, with scales

  • Dermal bone may be present but is not usually associated with scales
  • Osteoderms and gastralia may be present
  • Few skin glands that are mainly scent glands
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155
Q

Reptilian Scales

A
  • Usually lack underlying bony dermal contribution
  • Form from a fold in the surface epidermis
  • Can be modified into crests, spines and “horns”
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156
Q

Osteoderm

A

Small piece of dermal bone found under epidermal scales

- Found in some turtle shell bones, crocodilians, some lizards and extinct reptiles

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157
Q

Gastralia

A

Collection of dermal bone in the abdominal region

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158
Q

Epidermal Derivatives

A
  • Scales
  • Calluses
  • Nails
  • Claws
  • Hooves
  • Hair
  • Feathers
  • Baleen
  • Horns
  • Antlers
  • Glands
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159
Q

Nails, Claws and Hooves

A

Keratinized epidermal structures that tip the digits of amniotes

  • Protective
  • Functional in climbing, defence, food gathering, etc.
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160
Q

Horns and Antlers

A

Widespread cranial appendages that are used in defence, mate selection and dominance

  • True horns are a keratinized sheath supported by an unbranched bony core/spike; neither are shed
  • Antlers are usually confined to males and are a velvety shin until becoming bone when mature; shed annually; usually branched
  • Rhino horn is keratinized epithelium in the form of fused, hairlike epidermal papillae
  • Giraffe horns are ossified cartilage cores covered by skin
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161
Q

Hair

A

An exclusively mammalian feature that is formed from an epidermal sheath (follicle) that extends into the dermis

  • Grows basally with dermal papilla supplying blood vessels
  • Cells are pushed up, keratinized and die
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162
Q

Arrector Pili

A

Muscle associated with a hair follicle

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163
Q

Sebaceous Gland

A

Gland associated with a hair follicle that secretes an oily substance to lubricate and protect the hair

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164
Q

Apocrine Gland

A

Sweat glands that are associated with hair follicles in restricted areas
- Secrete viscous substances or pheromones

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165
Q

Glands

A 
Epidermal structures found in all vertebrate clades
Can be single celled or multicellular:
- Alveolar
- Tubular/coiled
- Complex or compound
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166
Q

Uropygial Gland

A

Gland near the base of the tail in birds that secretes an oily substance used in preening
- Protects feathers and repels water

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167
Q

Salt Gland

A

Gland on the head of some birds that is used to secrete excess salts

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168
Q

Eccrine Gland

A

Gland that secretes salt, urea or water

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169
Q

Mammary Gland

A

Modified apocrine gland used to secrete milk

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170
Q

Scent Gland

A

Modified apocrine gland used to mark territory, recognize other individuals and courtship

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171
Q

Skeleton

A

Supportive structure that is composed of various kinds of connective tissue

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172
Q

Connective Tissue

A

Consists of cells scattered through a matrix that is normally secreted by the cells

  • Formed from mesenchyme
  • Reinforces the epithelia and other soft body tissues
  • Acts as a support for the body
  • Proportion of cell types and materials involved determines structure, properties and function
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173
Q

Mesenchyme

A

Embryonic material that is formed mainly from the epimere and hypomere
- Forms a network of cells between the outer tube and developing organs

In adult, differentiates into

  • Connective tissue
  • Most of the circulatory system
  • Most of the muscles
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174
Q

Bone

A

Connective tissue of cells (osteocytes) deposited in a heavily mineralized matrix

  • Extremely metabolically active due to high vascularization
  • Osteocytes reside in lacunae within the matrix; connect with others
  • Grows by expansion at the surface
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175
Q

Cartilage

A

Connective tissue of variable types

  • Matrix is normally rigid but not as hard as bone
  • Chondrocytes reside in spherical, isolated lacunae
  • Not very metabolically active due to being avascular
  • Grows through both internal expansion and expansion at the surface
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176
Q

Bone vs Cartilage

A

It used to be thought that cartilage was primitive to bone, an idea that seemed to have embryological support since cartilage forms before bone in the embryo

  • However, the most primitive vertebrate so far recovered had an extensive bony exoskeleton and since then bone has been lost secondarily
  • Now considered to simply be different kinds of skeletal tissue
  • Bone better for compression
  • Fibrous cartilage better in tension
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177
Q

Parts of the Skeleton

A

Components that vary in structure, position and embryologic origin

Three broad classes

  • Dermal skeleton
  • Endoskeleton
  • Heterotopic skeletal elements
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178
Q

Dermal Skeleton

A

Membranous bone that forms directly in connective tissue

  • Relatively superficial in position
  • Forms mostly in the dermis
  • Never preformed in cartilage

Examples

  • Bony plates/scales in early fish
  • Osteoderms in crocodilians/turtles
  • Parts of the skull
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179
Q

Endoskeleton

A

Deeper lying bone that is almost always endochondral in formation

  • Replacement of embryonic cartilage by adult bony structures
  • Forms most bones in the body

Subdivisions

  • Somatic Skeleton
  • Visceral Skeleton
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180
Q

Somatic Skeleton

A

Skeleton from the outer tube of the body that is formed by somites

Two types:

  • Axial
  • Appendicular
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181
Q

Axial Skeleton

A

Most of the skull, vertebral column and axial ribs

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182
Q

Appendicular Skeleton

A

Paired appendages and limb girdles

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183
Q

Visceral Skeleton

A

Skeleton that is associated with branchial structures or derived from them
- Formed by the neural crest cells

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184
Q

Heterotopic Skeletal Elements

A

Stray skeletal elements that are not associated with other parts of the skeleton
- Not usually preformed in cartilage

Examples

  • Sesamoid bones
  • Bone in diaphragm in camels
  • Os cordis: bone in septum of heart in some ruminants
  • Bone in upper eyelid in crocodilians
  • Baculum, os clitoris
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185
Q

Diaphysis

A

Shaft of a long bone

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186
Q

Epiphysis

A

End of a long bone

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187
Q

Epiphyseal Line

A

Line that separates the diaphysis and epiphysis

- Formed from fusion of the epiphyseal plate

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188
Q

Epiphyseal Plate

A

Layer of hyaline cartilage that is found in juveniles between the epiphysis and diaphysis

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189
Q

Periosteum

A

Fibrous connective tissue that surrounds a bone

- Has a deep, bone-forming layer

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190
Q

Medullary Cavity

A

Cavity within the diaphysis of a bone within which blood cells are formed

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191
Q

Endosteum

A

Connective tissue lining the medullary cavity and spaces within a bone

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192
Q

Articular Cartilage

A

Cartilage found at the joints of bones

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193
Q

Development of Endochondral Bone

A
  1. Begins as a model of hyaline cartilage
  2. Bone begins to grow, radiating from the centre as the bone grows in length and the medullary cavity begins
  3. New centres of bone growth begin at the ends of the bone (epiphyses)
  4. Bone grows in width and new bone forms at the epiphyseal plate
  5. Epiphyses fuse and bone ceases growth
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194
Q

Postcranial Skeleton

A

All skeletal structures of the body not including the head

  • Largely formed by somatic endoskeletal elements
  • Axial and appendicular
  • Mesodermal in embryological origin
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195
Q

Vertebral Column

A

Major midline axial structure element

  • Formed by a series of repeating skeletal elements along the back
  • Little musculature attaching directly to vertebrae in fish, with most muscular force exerted on myosepta
  • Thus, ribs develop at the intersection of connective tissues to make muscular effort more efficient
  • Type of rib depends on position
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196
Q

Dorsal Rib

A

Typical rib that occurs at the intersection of the myoseptum and horizontal skeletogenous septum
- Formed from endochondral bone

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197
Q

Ventral Rib

A

Ribs that occur in fishes at the intersection of the myoseptum and connective tissue along the coelomic cavity

  • Not to be confused with gastralia and abdominal ribs
  • Formed from endochondral bone
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198
Q

Vertebrae

A

Each formed by various parts

  • Centrum is main structural element and articulates at either end with other centra
  • Different types depending on the form of their ends

Types

  • Amphicoelous
  • Procoelous
  • Opisthocoelous
  • Acoelous
  • Heterocoelous
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199
Q

Amphicoelous

A

Type of vertebra where the centrum is concave at both ends

- Typical of fishes and early tetrapods

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200
Q

Procoelous

A

Type of vertebra where the centrum is concave anteriorly and convex posteriorly
- Typical of amphibians and reptiles

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201
Q

Opithocoelous

A

Type of vertebra where the centrum is convex anteriorly and concave posteriorly
- Typical of amphibians and reptiles

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202
Q

Acoelous

A

Type of vertebra where the centrum is nearly flat on both ends
- Typical of the trunk of mammals and birds

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203
Q

Heterocoelous

A

Type of vertebra where the centrum is saddle shaped

- Typical of the neck vertebrae of birds

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204
Q

Evolution of Vertebrae

A

Tendency for there to be increased differentiation along the column in more advanced forms

  • Fish have trunk and caudal
  • Tetrapods have trunk, caudal and one or more sacral
  • More advanced tetrapods have cervical, dorsal, sacral and caudal
  • Mammals have cervical, thoracic, lumbar, sacral and caudal
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205
Q

Embryologic Development of Vertebrae

A

Develop from the sclerotome and are initially segmentally arranged

  • In fish, can be segmentally or intersegmentally arranged
  • In amniotes, become intersegmentally arranged with respect to musculature
  • Ensures musculature forms across adjacent vertebrae, otherwise muscle would not have functional role
  • Primary sclerotome migrates medially and toward the notochord and become rearranged
  • Form secondary sclerotome blocks made of cells that are originally from two adjacent primary sclerotomes
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206
Q

Appendicular Skeleton of Fish vs Tetrapods

A

Fish

  • Relatively simple and small
  • Pectoral > Pelvic

Tetrapods

  • Large and more complex; needed to keep body off ground and propel it
  • Pelvic > Pectoral
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207
Q

Pectoral Girdle of Bony Fish

A

Have lots of dermal bone in the skin

  • Pectoral girdle formed from dermal and endoskeletal bone
  • Fin supported by endoskeletal bone
  • Dermal elements add strength and anchor the pectoral girdle to body, mainly behind operculum; clavicle ventrally and dorsally attaching girdle to skull
  • Endoskeletal deep and posterior to dermal
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208
Q

Pectoral Girdle of Tetrapods

A

Gills have been lost, so a moveable neck is possible

  • Dermal elements are retained from fish except the dermal series
  • Cleithrum and clavicle strongly reduced
  • New interclavicle lies between the clavicles
  • Both cleithrum and interclavicle lost in more advanced vertebrates
  • Endoskeletal bones expand and the scapula begins to dominate
  • In mammals, essentially only the clavicle remains of the dermal elements, which tends to be reduced in cursorial mammals allowing for a more mobile scapula
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209
Q

Pelvic Girdle of Fish

A

Relatively small and is not attached to the body/vertebrae

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210
Q

Pelvic Girdle of Tetrapods

A

Fused to one or more sacral vertebrae through a dorsal extension of the girdle
- Hind limbs provide nearly all locomotive force

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211
Q

Evolution of Posture in Tetrapods

A

Early Tetrapods

  • Limbs perpendicular to body axis and extend laterally, causing a sprawled posture
  • Locomote mainly by fish-like movements

First Change: manus and pes rotate to point forward, but lateral bending of the body still propelled them

Later Tetrapods (Archosaurs, Therapsids)

  • Limbs tucked underneath body, more aligned to parasagittal plane
  • Appendages use for-aft motion to create more efficient locomotion
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212
Q

Skull

A

The skeletal structure of the head minus the lower jaw

- Complex fusion of dermal and endoskeletal elements

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213
Q

Shark Skull

A

Consists of a chondrocranium and palatoquadrate

  • Missing the dermal skull elements
  • A single structure that begins as separate cartilaginous centres of formation
  • Occipital region posteriorly: surrounds foramen magnum and occiptal condyle
  • Otic capsules: anterior widening of occipital region
  • Orbital region: narrowing anterior to the otic capsules
  • Ethmoid region contains nasal capsules
  • Braincase articulates ventrally with palatoquadrate
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214
Q

Braincase

A

The box surrounding the brain and sense organs to support and protect them

  • Complex series of single and paired bones
  • Mostly somatic endochondral bone
  • Some dermal bone

Dermal Bone
- Parasphenoid

Somatic Endochondral

  • Supraoccipital
  • Basioccipital
  • Exoccipitals
  • Opisthotic
  • Prootic
  • Basisphenoid
  • Sphenethmoid
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215
Q

Vertebrate (Bony) Skull

A

Three main parts

  • Braincase
  • Palatal complex
  • Skull roof
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216
Q

Palatal Complex

A

Series of bones that comprise the palate and articulation with the lower jaw

  • Has major articulations with other skull structures: lower jaw (via quadrate) and braincase (at basisphenoid via the epipterygoid)
  • Paired bones that are fairly complex
  • Mostly dermal bone
  • Some visceral endochondral bone

Dermal Bones (bear teeth in fishes and early tetrapods)

  • Pterygoids
  • Ectopterygoids
  • Palatines
  • Vomers

Visceral Endochondral Bones

  • Palatoquadrate
  • Quadrate
  • Epipterygoid
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217
Q

Skull Roof

A

Acts as a dorsal shield for the skull in bony vertebrates

  • Nearly solid with openings for the nostrils, eyes and pineal eye
  • Primitively notched posteriorly in the ear region
  • Dermal bone, generally paired

Five main series of bone

  • Tooth-bearing, marginal series
  • Midline series
  • Circumorbital series
  • Temporal series
  • Cheek series
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218
Q

Tooth-bearing Marginal Series

A

Series of the skull roof that forms the outer rim

Includes

  • Premaxilla
  • Maxilla
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219
Q

Midline Series

A

Series of the skull roof with adjacently paired bones on the dorsal side

  • Nasal
  • Frontal
  • Parietal
  • Postparietal
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220
Q

Circumorbital Series

A

Series of the skull roof that surrounds the orbit

  • Prefrontal
  • Postfrontal
  • Lacrimal
  • Postorbital
  • Jugal
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221
Q

Temporal Series

A

Series of the skull roof that lies between the otic notch and the midline series

  • Intertemporal
  • Supratemporal
  • Tabular (?)
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222
Q

Cheek Series

A

Series of the skull roof that lies behind the orbit and below the otic notch

  • Squamosal
  • Quadratojugal
  • Quadrate
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223
Q

Pterygoid

A 
Largest bone of the palatal complex
Paired
- Largest of the four
- Posterior
- Median
- Dermal bone
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224
Q

Ectopterygoid

A

Bone of the palatal complex
Paired
- Posterior and lateral
- Dermal bone

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225
Q

Palatine

A

Bone of the palatal complex
Paired
- Lateral and between the ectopterygoid and vomer
- Dermal bone

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226
Q

Vomer

A

Bone of the palatal complex
Paired
- Anterior and lateral
- Dermal bone

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227
Q

Palatoquadrate

A

Bone of the palatal complex
Paired
- Visceral endochondral bone
- Largely replaced functionally by dermal elements, but usually remains as a reduced structure
- Four ossifications may form along it in fishes, but only two in tetrapods: quadrate and epipterygoid

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228
Q

Quadrate

A 
Bone of the palatal complex
Paired
- Ossification of the palatoquadrate in tetrapods
- Small and posterior
- Articulates with the lower jaw
- Visceral endochondral bone
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229
Q

Epipterygoid

A 
Bone of the palatal complex
Paired
- Ossification of the palatoquadrate in tetrapods
- Large and anterior
- Articulates with the braincase
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230
Q

Parasphenoid

A

Bone of the braincase
Paired
- Forms the ventral part of the braincase
- Narrow anteriorly and wide posteriorly
- Dermal bone
- Forms from the skin on the roof of the oral cavity

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231
Q

Supraoccipital

A

Bone of the braincase that forms part of the occipital
Single
- Dorsal to the foramen magnum

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232
Q

Basioccipital

A

Bone of the braincase that forms part of the occipital
Single
- Ventral to the foramen magnum

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233
Q

Exoccipital

A

Bone of the braincase that forms part of the occipital
Paired
- To the left and right of the foramen magnum

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234
Q

Occipital

A

Single bone that forms the posterior part of the skull and is typically fused from the supraoccipital, basioccipital and exoccipitals

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235
Q

Opisthotic

A

Bone of the braincase that is associated with the otic region
Paired
- Posterior to the prootic
- Contains the sacs and canals of the inner ear

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236
Q

Prootic

A

Bone of the braincase that is associated with the otic region
Paired
- Anterior to the opisthotic
- Contains the sacs and canals of the inner ear

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237
Q

Basisphenoid

A

Bone of the braincase that forms the floor of the cranial cavity
Single
- Median and mostly ventral/anterior to otic region
- Mostly covered ventrally by the parasphenoid
- Forms basal articulation with the palatal complex via the basipterygoid process

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238
Q

Sphenethmoid

A

Bone of the braincase that contains the olfactory nerves
Single
- Trough shaped, median ossification
- In sphenoid and ethmoid regions

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239
Q

Basic changes in tetrapod skulls

A

Early tetrapods
- Skull is formed of many different bones

Later forms

  • Many bones are lost or fused, leading to fewer total bones
  • Many elements are rearranged
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240
Q

Basal Amniote Skull

A

Similar to that of an early tetrapod, but with some changes

  • Otic notch closed
  • Intertemporals lost
  • Other temporal bones reduced and displaced posteriorly
  • Postparietals and tabular change, eventually become fused to occipital
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241
Q

Pelycosaur Skull

A

First intermediate stage toward a mammalian skull

- Temporal fenestra is developed

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242
Q

Non-Mammalian Therapsid Skull

A

Second intermediate stage toward a mammalian skull

  • Enlargement of the temporal fenestra
  • Quadratojugal reduced and eventually lost
  • Squamosal differentiates, with part becoming the zygomatic arch and part helping form the braincase
  • Loss of the prefrontals, postfrontals and postorbitals
  • Original three skull areas are integrated
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243
Q

Anapsid Skull

A
  • Small brain sits in braincase
  • Dermal skull roof covers brain
  • No fenestra in skull roof
  • Jaw muscles attach to inside of dermal skull roof
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244
Q

Early Synapsid Skull

A
  • Brain somewhat larger than anapsid
  • Dermal skull roof covers brain
  • Fenestra exists but is covered by heavy connective tissue
  • Jaw muscles attach to inside of skull roof and fenestrae
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245
Q

Early Therapsid Skull

A
  • Brain larger than in early synapsids
  • Temporal fenestrae have enlarged
  • Cranial kinesis is lost
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246
Q

Later Therapsid Skull

A
  • Brain and temporal fenestra still growing
  • Dermal bone begins to grow downwards
  • Braincase grows upwards, mainly in the epipterygoid and alisphenoid; begins to enclose brain
247
Q

Mammal Skull

A
  • Large brain is completely enclosed by dermal and braincase bone
  • Muscles have transitioned from inside the skull to outside
  • Few original skull bones left, and many are visible but not on the same surfaces as in earlier forms
  • Most surfaces represent new growth underneath the muscles
248
Q

Secondary Palate

A

Separation of the passages for food and air

  • Allows animal to breathe and process food at the same time
  • Premaxillae and maxillae downturn and expand medially to cover the original roof of the oral cavity
  • Palatines also contribute posteriorly
249
Q

Primary Palate

A

Food and air pass through the same long passage and mix together

  • Animals stop breathing when they process food
  • Not too bad for most non-amniotes since amphibians respire through their skin most of the time
  • Problem for warm-blooded animals since they can’t stop breathing for long periods in order to maintain body temperature
250
Q

Development of the Temporal

A

Involves complex fusion of dermal and endochondral braincase elements

Includes

  • Squamosal
  • Petrosal
  • Ectotympanic
  • Entotympanic
  • Malleus
  • Incus
  • Stapes
251
Q

Squamosal

A

Large, flat bone on the side of the brain
Paired
- Dermal
- Forms the major part of the temporal

252
Q

Petrosal

A

A.K.A. Periotic, petromastoid
Bone of the braincase that forms from fusion of the prootic and opisthotic
- Forms the inner part of the temporal

253
Q

Ectoympanic

A

Bone that is formed from the primitive angular, so was once part of the lower jaw

  • Dermal bone
  • Forms the outer rim of the external auditory meatus
254
Q

Entotympanic

A

Bone that has been newly formed in mammals from the braincase
- Forms the base of the middle ear, lateral to the basioccipital

255
Q

Malleus

A

Middle ear ossicle that is formed from the primitive articular

  • Dermal bone
  • From the old lower jaw
256
Q

Incus

A

Middle ear ossicle that is formed from the primitive quadrate

  • Endochondral bone
  • From the palatal complex
257
Q

Stapes

A

Middle ear ossicle that is formed from the primitive hyomandibular
- Visceral endochondral bone

258
Q

Sphenoid Region

A

Embryologically complex region from which many cranial nerves emerge

Formed from

  • Presphenoid and basisphenoid ventrally
  • Orbitosphenoid adjacent to the presphenoid
  • Alisphenoid adjacent to the basisphenoid
259
Q

Anterior Sphenoid Region

A

Forms from the braincase and begins as three separate elements in mammals that then fuse together

  • Presphenoid and orbitosphenoid
  • Although fused, they cannot be seen externally at the same time in an adult and are separate embryologically
260
Q

Posterior Sphenoid Region

A
  • Basisphenoid (from the braincase)

- Alisphenoid (homologous to the epipterygoids)

261
Q

Presphenoid

A

Anterior and ventral portion of the sphenoid region

Single

262
Q

Orbitosphenoid

A

Anterior and lateral portion of the sphenoid region
Paired
- Optic foramen
- Orbital fissure on very posterior part

263
Q

Basisphenoid

A

Posterior and ventral portion of the sphenoid region

Single

264
Q

Alisphenoid

A 
Posterior and lateral portion of the sphenoid region
Paired
- Orbital fissure on very anterior part
- Foramen rotundum in middle
- Foramen ovale on posterior side
265
Q

Muscle Categories

A

Histological

  • Striated
  • Smooth

Physiological

  • Voluntary
  • Involuntary

Organizational

  • Somatic
  • Visceral
266
Q

Somatic Muscles

A

Muscles that are derived from the myotomes of somites

  • Axial and appendicular musculature
  • Always striated
  • Mostly voluntary
  • Innervated by somatic motor fibres
267
Q

Visceral Muscles

A

Muscles that are derived from the mesenchyme

  • Branchiomeric and smooth (gut) musculature
  • Can be smooth or striated
  • Mostly involuntary
  • Innervated by visceral motor fibres
268
Q

Origin

A

The end of a muscle that is proximal
OR
moves the least during contraction

269
Q

Insertion

A

The end of a muscle that is distal
OR
moves the most during contraction

270
Q

Flexor

A

A muscle that closes a hinge joint

271
Q

Extensor

A

A muscle that opens a hinge joint

272
Q

Adductor

A

A muscle that moves something towards the ventral midline

In the jaw, this muscle closes the jaw

273
Q

Abductor

A

A muscle that moves something away from the ventral midline

274
Q

Depressor

A

A muscle that opens the jaw

275
Q

Appendicular Musculature

A

Any muscle in which either end attaches to part of an appendage including the pectoral or pelvic girdle

276
Q

Axial Musculature

A

Any muscle that does not at any point attach to part of an appendage

  • Consists of a series of myomeres
  • Segmentally arranged since it’s derived from myotomes
  • Begin as simple transverse bands but develop into complex zigzag patterns, helping facilitate the smooth curving action of the body
  • Division between epaxial and hypaxial along horizontal skeletogenous septum
  • Most of the body’s bulk in a fish
277
Q

Epaxial Musculature

A

Dorsal portion of the axial musculature

  • In fish and amphibians, basically a single segmented block known as the dorsalis trunci
  • Generally reduced in tetrapods since the appendages take over, so restricted to between the neural and transverse processes
  • Longitudinally subdivided into iliocostalis, longissimus dorsi and transversospinalis in reptiles and mammals
  • Segmented in reptiles but not in mammals
  • Mammals have complex origin and insertion patterns
278
Q

Hypaxial Musculature

A

Ventral portion of the axial musculature

  • Smaller than the epaxial musculature in fish, where they are also a single unit
  • In tetrapods, reduced to form thin muscular sheets around the flanks and belly; support abdominal cavity and viscera
  • Much of the musculature in tetrapods is attached to the ribs with complex attachments and subdivisions

Three Groups

  1. Subventral Series
  2. Lateral (Flank) Series
  3. Ventral (Belly) Series
279
Q

Horizontal Skeletogenous Septum

A

Septum that divides the epaxial from hypaxial musculature

280
Q

Dorsalis trunci

A

Epaxial musculature in fish and amphibians

281
Q

Iliocostalis

A

Lateral part of the epaxial musculature in reptiles and mammals
- Attaches to the ribs

282
Q

Longissimus dorsi

A

Largest part of the epaxial musculature in reptiles and mammals
- Dorsal to the transverse processes

283
Q

Transversospinalis

A

Dorsal part of the epaxial musculature in reptiles and mammals
- Lies between the longissimus dorsi and neural spines

284
Q

Subvertebral Series

A

Dorsal and medial series of hypaxial musculature in tetrapods
- Underneath the transverse processes of the vertebrae

285
Q

Ventral Series

A

Midventral muscle in the hypaxial musculature in tetrapods

- Rectus abdominis

286
Q

Rectus abdominis

A

Single muscle of the ventral series in tetrapods

- Stretches from the sternum to the pelvis

287
Q

Lateral Series

A

Series of the hypaxial musculature that lies between the transverse processes of the vertebrae and the rectus abdominis

  • Primitively segmented
  • Rather uncomplicated when ribs are reduced or in the lumbar region
  • In rib area muscles are complex and further subdivided
  • All muscles connected to ventral midline through aponeuroses

Become three unbroken sheets of muscles whose fibres extend mostly perpendicular to one another, strengthening them

  1. External oblique
  2. Internal oblique
  3. Transverse abdominis
288
Q

External oblique

A

Most superficial of the lateral series of musculature

289
Q

Internal oblique

A

Intermediate layer of the lateral series of musculature

290
Q

Transverse abdominis

A

Most deep layer of the lateral series of musculature

291
Q

Aponeurosis

A

A sheet-like tendon that acts as an insertion for a muscle

  • Since the viscera are mostly liquid there is no need for long muscle fibres to compress them (since liquids are essentially incompressible)
  • Produces around the same strength as the muscle against breakage and torsion, but with less volume
  • Decreases relative length of contraction but not strength
292
Q

Cranial Muscles

A

The muscles found in the head and neck/gill region
- Can be recognized through innervation

Somatic component

  • Axial musculature
  • Derived from myotomes and epimeres

Visceral component

  • Branchiomeric musculature
  • Derived from neural crest cells
293
Q

Axial muscles of the head and neck

A

Three groups

  • Extrinsic eye muscles
  • Epibranchial
  • Hypobranchial
294
Q

Extrinsic Eye Muscles

A

Axial muscles that radiate from the orbit of the skull and allow the eye to move

  • Six muscles that remain unchanged throughout vertebrate evolution
  • Formed from three pre-otic somites/myotomes
295
Q

Epibranchial Musculature

A

Axial muscles that are the anterior extension of the epaxial musculature

  • Extends forward to help move and control the neck and head
  • Gills lie between this and the hypobranchial musculature
296
Q

Hypobranchial Musculature

A

Axial muscles that are the anterior extension of the hypaxial musculature

  • Mainly extends between the shoulder girdle and the jaw, modified as throat muscles including the tongue in tetrapods
  • Gills lie between this and the epibranchial musculature
297
Q

Ventral oblique

A

One of the extrinsic eye muscles

  • Extends from the anterior part of the orbit and ventrally
  • Arises from the first pre-otic myotome
  • Innervated by the oculomotor nerve
298
Q

Medial rectus

A

One of the extrinsic eye muscles

  • Extends from the posterior part of the orbit to the anterior and medial end of the eye
  • Arises from the first pre-otic myotome
  • Innervated by the oculomotor nerve
299
Q

Dorsal rectus

A

One of the extrinsic eye muscles

  • Extends from the posterior part of the orbit to the dorsal part of the eye
  • Arises from the first pre-otic myotome
  • Innervated by the oculomotor nerve
300
Q

Ventral rectus

A

One of the extrinsic eye muscles

  • Extends from the posterior part of the orbit to the ventral part of the eye
  • Arises from the first pre-otic myotome
  • Innervated by the oculomotor nerve
301
Q

Dorsal oblique

A

One of the extrinsic eye muscles

  • Extends from the anterior part of the orbit and dorsally
  • Arises from the second pre-otic myotome
  • Innervated by the trochlear nerve
302
Q

Posterior rectus

A 
A.K.A. Lateral rectus
One of the extrinsic eye muscles
- Extends from the posterior part of the orbit to the posterior part of the eye
- Arises from the third pre-otic myotome
- Innervated by the abducens nerve
303
Q

Coracoarcuals

A

Muscles from the hypobranchial musculature that opens the jaws in fishes

304
Q

True Tongue

A

A muscular structure that is only present in tetrapods

- Formed from hypobranchial musculature

305
Q

Primary Tongue

A

Non-muscular tongue that is present in fishes

306
Q

Genioglossus

A

Muscle that extends from the chin to the tongue

- Formed from hypobranchial musculature

307
Q

Geniohyoid

A

Muscle that extends from the chin to the hyoid apparatus

- Formed from hypobranchial musculature

308
Q

Styloglossus

A

Muscle that extends from the stylohyoid of the hyoid apparatus to the tongue
- Formed from the hypobranchial musculature

309
Q

Hyoglossus

A

Muscle that extends from the hyoid to the tongue

- Formed from the hypobranchial musculature

310
Q

Thyrohyoid

A

Muscle that extends from the thyroid cartilage to the hyoid

- Formed from the hypobranchial musculature

311
Q

Sternohyoid

A

Muscle that extends from the sternum to the hyoid

- Formed from the hypobranchial musculature

312
Q

Sternothyroid

A

Muscle that extends from the sternum to the thyroid cartilage
- Formed from the hypobranchial musculature

313
Q

Branchiomeric Musculature

A

Musculature that is associated with the visceral arches

  • Formed from the mesenchyme
  • Visceral
  • Striated

Ancestral vertebrates have visceral arches with each arch associated with a set of muscles

In higher vertebrates, the gills are lost so muscles no longer function as gut muscles
- Become muscles of the jaw, face and shoulder

314
Q

Superficial constrictor

A

Continuous, superficial muscle sheet that separates adjacent pharyngeal slits

315
Q

Interbranchial

A

Continuous, deep muscle sheet that separates adjacent pharyngeal slits

316
Q

Interarcual

A

Branchiomeric muscle that stretches between the pharyngobranchial and the epipbranchial of a pharyngeal arch

317
Q

Levator

A

Branchiomeric muscle that extends from the epibranchial of a pharyngeal arch to the dorsal midline

318
Q

Adductor

A

Branchiomeric muscle that extends between the epibranchial and ceratobranchial of a phayngeal arch

319
Q

Pharyngeal Muscles in Fish

A
  • Individual levators are lost and fuse into single cucullaris
  • Superficial constrictors and interbranchials lost in bony fishes due to operculum
320
Q

Pharyngeal Muscles in Tetrapods

A
  • Cucullaris replaced by the trapezius

- Almost all other muscles supporting the gill arches disappear with them, though a few remain in the larynx

321
Q

Trapezius

A

Dorsal shoulder muscle that arises from the mid-dorsal line and inserts on the shoulder

322
Q

Sternocleidomastoid

A

Shoulder muscle that extends from the ventral part of the shoulder to the back of the skull

323
Q

Muscles of the Hyoid Arch in Fish

A
  • Innervated by the facial nerve (CN VII)
  • Many muscles lost because hyoid arch acting as jaw support
  • Superficial constrictor, levator remain
324
Q

Muscles of the Hyoid Arch in Tetrapods

A
  • Superficial constrictor modified into a sheet around the neck known as the sphincter colli
  • Depressor mandibulae forms from anterior end of sphicter colli and opens mouth
325
Q

Sphicter Colli

A

Sheet muscle that wraps around the neck in tetrapods

  • Formed from the superficial constrictor of the hyoid arch
  • Modified in mammals to form the facial muscles and some jaw-opening muscles
326
Q

Depressor Mandibulae

A

Muscle that opens the mouth in tetrapods and extends from the back of the skull to the back of the lower jaw

  • Formed from the anterior part of the sphicter colli
  • Lost in mammals
327
Q

Facial Muscles

A

Expansion of the sphicter colli to be used in muscles for facial expression
- Only found in mammals

328
Q

Buccinator

A

Prominent facial muscle in mammals, muscle of the cheek

- Important for chewing as it keeps food in the oral cavity for processing

329
Q

Digastric

A

Two-part muscle in mammals that is used in jaw opening

  • Replaces the depressor mandibulae
  • Posterior belly formed from sphincter colli
  • Anterior belly formed from mylohyoid
330
Q

Muscles of the Mandibular Arch in Dogfish

A

Three groups

  1. Adductor mandibulae
  2. Dorsal levator/Levator palatoquadrati
  3. Ventral muscles inc. intermandibularis
331
Q

Adductor mandibulae

A

Mandibular arch muscle in dogfish that forms at the angle of the jaws and closes the mouth

  • Becomes more complex in more derived forms but remains stretching from underneath the skull roof to the lower jaw
  • In mammals, there is a complete reorganization of these muscles due to reorganization of the skull bones
332
Q

Dorsal levator

A

A.K.A. Levator palatoquadrati
Mandibular arch muscle that extends from the palatoquadrate to the dorsal midline
- Remains as a complex muscle as long as the skull is kinetic, but is lost once the skull fuses to the braincase

333
Q

Intermandibularis

A

Mandibular arch muscle that stretches between the left and right lower jaws
- Remains throughout vertebrate evolution but becomes the mylohyoid in mammals

334
Q

Mylohyoid

A

Muscle that stretches betwen the left and right lower jaws in tetrapods

  • Homologous to the intermandibularis, but with a different name
  • Becomes the anterior belly of the digastric in mammals
335
Q

Mammalian Adductor Musculature

A

Three main muscles used to close the mouth

  • Temporalis
  • Masseter
  • Pterygoid muscles
336
Q

Temporalis

A

Jaw adductor in mammals that is large and passes from the temporal fossa to the lower jaw

337
Q

Masseter

A

Jaw adductor in mammals that passes from the zygomatic arch to the lower jaw
- Can be quite large in some mammals (like rodents)

338
Q

Pterygoid Muscles

A

Jaw adductors in mammals that extend from the pterygoid region of the skull to the lower jaw

  • Have internal and external portions
  • Control the medio-lateral motions of the jaw
339
Q

Respiratory System

A

The system responsible for obtaining oxygen from the environment and carrying it to the blood stream

  • Organs are found in or derived from the pharynx in most vertebrates
  • Gills are used in fishes, while lungs are generally used in tetrapods (along with the skin in amphibians)
340
Q

Gills

A

The typical respiratory organ found in fishes and juvenile/neotenic amphbians
- Are found along the walls of the pharyngeal slits in fish

341
Q

Pharynx

A

The anterior part of the gastrocoele in an embryo

- The “throat,” where gill pouches occur in the embryo

342
Q

Development of the Pharyngeal Slits

A

Forms through the pocketing of the ectoderm and endoderm in the pharyngeal area until these pockets meet to form a passage

343
Q

Pharyngeal Slits in Fishes

A

Almost always consists of five slits and an optional spiracle

344
Q

Pharyngeal Slits in Cyclostomes

A

Number varies, but they are spherical pouches with small, circular external openings
- Can have each pouch open individually to the outside or can have them join together into a common external opening

345
Q

Pharyngeal Modifications in Cyclostomes

A

Liquid diet can interfere with the respiratory system, so during metamorphosis they develop a horizontal separation of the pharynx

  • Split into a dorsal “esophagus” and a ventral respiratory tube
  • Isolation of the respiratory tube occurs by closing of the velum
346
Q

“Esophagus”

A

Dorsal portion of the pharynx in cyclostomes that is used for passage of food

347
Q

Respiratory Tube

A

Ventral portion of the pharynx in cyclostomes where there pharyngeal slits lie and function in respiration

  • Functions when velum closed by pumping water in and out through external pharyngeal openings
  • Nasal opening used in hagfish
348
Q

Velum

A

Flap-like valve in cyclostomes that can isolate the respiratory tube from the “esophagus”
- Remains open unless the animal is feeding

349
Q

Pharyngeal Slits in Sharks

A

Due to interbranchial septa, each slit has a separate opening

350
Q

Pharyngeal Slits in Teleosts

A

Due to the presence of the operculum, there is a single opening to the outside world
- Allows for interweaving of gill lamellae, and therefore a more efficient respiratory system

351
Q

Respiratory System in Tetrapods

A

Since the gills are lost, respiration usually takes place with lungs
- Pharynx becomes smaller and functionally less important, but is the entrance to the lungs through the glottis

352
Q

Glottis

A

Opening in the floor of the pharynx in tetrapods that serves as the entrance to the lungs

353
Q

Lungs

A

Main breathing apparatus in tetrapods

  • Form from the ventral part of the pharynx, so extend ventrally from it
  • Are actually not very efficient respiratory organs since air goes in and out of the same tube so there is always some unexpelled deoxygenated blood
  • Complexity and surface area tends to increase in more derived and active tetrapods
354
Q

Swimbladder

A

Organ found in teleosts that resembles the lungs of tetrapods but is dorsal in position

  • Functions mostly in buoyancy through changing the specific gravity
  • In advanced teleosts, the connection between the swimbladder and pharynx is lost completely
  • When connected, performs some respiratory functions
  • Actually likely that swimbladders are specializations of lungs
355
Q

Bronchi

A

Tubes that branch from the trachea towards the lungs

- Have primary and secondary branching

356
Q

Bronchioles

A

Tubes that branch from the bronchi towards the lungs

357
Q

Alveoli

A

Small blind-ended sacs that occur at the terminal ends of bronchioles within the lungs

358
Q

Respiratory System of Birds

A

Complex and efficient system that allows them to be active at lower concentrations of oxygen than mammals

  • Lungs are quite compact, but the system is continued through various air sacs that are distributed through the trunk and bones
  • Allows for one-way passage of air and near complete expulsion of carbon dioxide
  • Air bypasses the lungs as it enters the system and goes to the posterior air sacs
  • Moves from posterior air sacs to lungs, where gas exchange occurs
  • Air them moves from lungs to anterior air sacs before being expelled
359
Q

Parabronchi

A

Tiny tubes in the respiratory system of birds that facilitate air exchange to the lungs

360
Q

The two-cycle respiration system

A

Cycle 1

  • Inhalation: air goes to posterior air sacs
  • Exhalation: air moves from PAS to lungs via parabronchi

Cycle 2

  • Inhalation: air moves from lungs to anterior air sacs
  • Exhalation: air moves from AAS to trachea and out
361
Q

Cutaneous Respiration

A

Capacity of many vertebrates to exchange gas through the skin or internal surfaces, like the lining of the oral cavity

  • Usually limited, so used as an accessory function
  • However, can perform the majority of respiration in most amphibians and all of it in lungless salamanders
  • Amphibians may develop extensions of the skin to increase the surface area on which this can occur
362
Q

Digestive System

A

System involved in obtaining nutrients from food

  • Includes various organs, mainly specializations of the digestive tube
  • Includes: esophagus, stomach, intestines, mouth, pharynx, accessory organs (liver, pancreas)
  • Functions in transport of food items, mechanical digestion, chemical digestion and absorption
363
Q

Mechanical Digestion

A

Physical treatment of food in the digestive system

  • Action of the visceral muscles that surround the gut
  • Peristalsis
  • Reduces food for chemical digestion
364
Q

Peristalsis

A

Wave-like contractions of the diestive system used in mechanical digestion

365
Q

Chemical Digestion

A

Breakdown of food into molecular components for absorption

366
Q

Absorption

A

Passage of molecular food substances through the gut wall and into the cardiovascular or lymphatic vessels

367
Q

Divisions of the Gut

A
  • Many vertebrates have distinct parts of the gut, but they are not always comparable to the human condition of well-defined segments
  • Often divided into thirds, but that is not applicable to all vertebrates
  • Main parts are foregut and hindgut
368
Q

Pylorus

A

Constriction at the beginning of the small intestine

  • Almost always recognizable in vertebrates
  • Divides the foregut from the hindgut
369
Q

Foregut

A

The portion of the gut that takes food to where it is treated

  • Little chemical digestion
  • Can be a simple tube with no stomach in amphioxus, cyclostomes and some fishes
  • In some fishes, the stomach is present but the esophagus is short and ill-defined
  • May see specializations of the esophagus in some tetrapods, but mostly stay simple

Includes

  • Pharynx
  • Esophagus
  • Stomach
370
Q

Esophgus

A

Fairly think pipe that is the connection between the pharynx and the stomach
- Distinct from the pharynx mainly in gross morphology

371
Q

Stomach

A

Large sac at the posterior end of the foregut

  • Boundary may be indistinct as in the shark, but in higher vertebrates a sphincter is present
  • Arises as a major organ in jawed vertebrates and the advent of carnivory
  • Originally functioned to dump food, feed it at a constant rate to the intestine, and break it down through peristalsis
  • Now, some chemical digestion occurs within it: gastric juices
372
Q

Hindgut

A

Portion of the gut that consists essentially of the intestine(s)
- Usually responsible for most chemical digestion and absorption

373
Q

Intestine

A

Organ where most absorption occurs
Can come in different forms:
- Valvular, as in sharks
- Subdivisions of small and large, as in mammals

374
Q

Small Intestine

A

Anterior portion of the intestinal tract

Three sections

  • Duodenum
  • Jejunum
  • Ileum
375
Q

Duodenum

A

First loop of the small intestine

376
Q

Ileocecal Valve

A

Represents the separation between the small and large intestine

377
Q

Large Intestine

A

A.K.A. Colon
Mainly functions in storage and water resorption
- Shorter than the small intestine, but wider
- Ends in the rectum or cloaca

Subdivisions

  • Ascending
  • Transverse
  • Descending
  • Sigmoid
378
Q

Cloaca

A

Ending of the digestive as well as other systems (urogenital mainly)

379
Q

Rectum

A

Ending of the digestive system alone

380
Q

Cecum

A

Outpocketing of the digestive system that typically occurs between the large and small intestine

  • One in mammals, two in birds
  • Found between the stomach and intestine in fish
  • Can be variably developed and variable in size
381
Q

Pyloric Cecum

A

Ceca occurring between the stomach and intestine, as in fish

- Three occur in the perch

382
Q

Crop

A

Specialization of the esophagus in birds that results in a sac for temporary food storage

383
Q

Salivary Glands

A

Glands present in the oral cavity of most vertebrates

  • Important for swallowing
  • Many tetrapods have enzymes in saliva that help digest starch
  • Some may evolve into poison glands
384
Q

Proventriculus

A

Proximal, glandular part of the stomach in birds

- Secretes gastric juices to aid in digestion

385
Q

Gizzard

A

Distal, muscular portion of the stomach in birds

  • Contains grit and/or pebbles to help grind large, hard foodstuffs
  • Helps with absence of teeth
  • Also present in crocodilians, but at the anterior part of the stomach
386
Q

Ruminant Stomach

A

Four-chambered stomach system that is actually formed from both the esophagus and the stomach

  • Also find a three-chambered system as in camels
  • Essentially a fermentation system: some chambers support microorganisms that digest the cellulose wall of plant cells
  • Plant material lower in energy and protein than meat and requires large, complex digestive systems

Esophagus

  • Rumen
  • Reticulum
  • Omasum

Stomach
- Abomasum

387
Q

Ruminant Digestion

A

Rumen

  • Fermentation chamber where cellulose is broken down
  • Amino acids, proteins, vitamins may also be produced
  • Cud them regurgitated and chewed again into finer particles

Reticulum, Omasum & Abomasum

  • After regurgitation, cud is swallowed into these chambers
  • Walls may absorb nutrients, a trait restricted to the small intestine in most mammals
388
Q

Increasing Surface Area of the Intestine

A

Four Methods

  1. Lengthen
  2. Spiral Valve
  3. Cecum
  4. Roughen internal surface
389
Q

Lengthening of the intestine

A

Results in a longer tube and therefore more surface area

- Mainly seen in teleosts and tetrapods

390
Q

Spiral valve in the intestine

A

Results in lengthening and slowing of food passage

  • Typically seen in primitive jawed fish
  • Typhosole of lamprey may be related
391
Q

Roughening of intestinal surface

A

Results in villi or microvilli of the internal lining of the intestine

392
Q

Villi

A

Finger-like projections of the internal lining of the intestine

393
Q

Microvilli

A

Projections found on the individual cells within the intestine

394
Q

Mouth

A

Opening into the oral cavity
- Forms as an inpocketing of the ectoderm, and the boundary between the ectoderm and endoderm breaks down to complete the passage

395
Q

Stromodeum

A

Initial inpocketing of the ectoderm in the embryo that eventually forms the mouth and oral cavity

396
Q

Oral Cavity

A

A.K.A. Buccal cavity

  • Limits can be compared between vertebrates depending on the placement of Rathke’s pouch and the nasal pit
  • These form a single pit in cyclostomes
397
Q

Rathke’s Pouch

A

A.K.A. Hypophyseal pouch
Middorsal pit in the rood of the stomodeum of the embryo
- Later, helps form the hypophysis
- Behind the eye in fishes and tetrapods

398
Q

Nasal Pit

A

A.K.A. Nasal placode

Small pocketing of the stomodeum in the embryo that forms the olfactory epithelium

399
Q

Structures in the Oral Cavity

A
  • Tongue in terrestrial vertebrates
  • Vomeronasal Organ
  • Various Oral Glands
400
Q

Uses of the Tongue

A
  • Manipulation of food and intraoral transport
  • Swallowing
  • May be elongated to aid in capture of food (frogs, many lizards, salamanders, some mammals, birds)
  • Taste buds
  • May transport chemicals to vomeronasal organ
401
Q

Vomeronasal Organ

A

A.K.A. Jacobson’s Organ

Organ in the roof of the oral cavity used in the chemical detection of pheromones and prey

402
Q

Oral Glands

A

Various glands in the oral cavity that secrete a variety of things

  • Mostly absent in fish aside from a few that secrete mucus
  • Lampreys have glands that secrete an anticoagulant
  • Salivary glands are common in terrestrial vertebrates
  • Poison glands
403
Q

Pharyngeal Glands

A

Glands that develop in the pharynx

  • Thyroid
  • Thymus
404
Q

Thyroid Gland

A

Gland in the pharynx that secretes hormones important to metabolism, growth, reproduction and development of the nervous system

  • Begins as a midventral outgrowth of the pharynx and is formed of follicles
  • In many fish, but not sharks, the follicles are scattered in the pharynx
  • In tetrapods, there exist discrete glands
  • Migrates posteriorly to the end of the trachea in more and more derived tetrapods
  • Endostyle of tunicates and amphioxus the homologue of the gland
405
Q

Thymus Gland

A

Gland at the base of the neck that develops lymphocytes and functions as part of the immune system

  • Develops from pharyngeal pouches
  • More prominent in juveniles and tends to become reduced in older individuals
406
Q

Denticles

A

Keratinized, tooth-like cones present in cyclostomes

  • Associated with the mouth and rasping tongue
  • Used to cling to prey and rasp off flesh
407
Q

True teeth

A

Present in all gnathostomes except those in which they have been secondarily lost

  • Epidermal and dermal in origin
  • Usually occur as part of the marginal series but may occur elsewhere in the jaw as well
  • Palatal teeth in many fishes, amphibians and reptiles
  • Pharyngeal teeth on the visceral arches of many teleosts
408
Q

Homodont

A

Teeth that are simple, conical, and similar along the entire margin
- Condition of fishes and reptiles

409
Q

Heterodont

A

Teeth that are complex and differentiated

- Mammalian teeth

410
Q

Acrodont

A

Teeth that are loosely attached to the jaw by ligaments

  • Sit on top of the jaw
  • Seen in teleosts, Sphenodon
411
Q

Pleurodont

A

Teeth that are braced on one side, so half in a socket

- Condition of many lizards

412
Q

Thecodont

A

Teeth that are fully placed into a socket in the jaw

- Mammals, archosaurs

413
Q

Crown

A

Portion of a tooth that is exposed above the gumline

414
Q

Root

A

Portion of a tooth that is placed within a socket (if present)

415
Q

Alveolus

A

Socket within which a tooth sits in the jaw

416
Q

Pulp Cavity

A

Cavity within a tooth in which blood vessels and nerves reside

417
Q

Enamel

A

Substance that typically covers the crown of a tooth

  • Hardest substance in the body
  • Is not always present
418
Q

Dentine

A

Substance that forms the bulk of a tooth

- Main supporting structure

419
Q

Cementum

A

Substance that typically lines the root of a tooth

  • Can anchor the root to the alveolus
  • Can be expanded and present on the crown of the tooth
420
Q

Polyphyodonty

A

Condition where teeth are continuously replaced throughout the animal’s lifetime

  • Replacement is complex and occurs in successive waves where adjacent teeth are out of phase with one another
  • Typical of most lower vertebrates
421
Q

Diphyodonty

A

Condition where teeth are replaced only one in life, and an animal has a set of juvenile and adult teeth
- Typical of most mammals

422
Q

Monophyodonty

A

Condition where teeth are never replaced

- Typical of toothed whales and sloths

423
Q

Incisors

A

Mammalian teeth found in the premaxilla

424
Q

Canines

A

Mammalian teeth that are the first found in the maxilla or at the premaxillo-maxillary suture
- Some may be incisiform

425
Q

Premolars

A

Mammalian cheek teeth that follow the canines and have a deciduous precursor

  • Some may be molariform
  • In juvenile dentition, perform the function of molars so may be called deciduous molars
426
Q

Molars

A

Mammalian cheek teeth that follow the premolars and do not have a deciduous precursor

427
Q

Ancestral Tooth Formula of Placental Mammals

A

3/3 : 1/1 : 4/4 : 3/3

428
Q

Coelom

A

Space within the body that contains various organs and structures

  • Begins as two spaces that later partially merge
  • Forms from the hypomere of the mesoderm, which splits internally to form pouches that expand into two large, bilateral spaces
  • Left and right halves initially separated by two layers of splanchnic pritoneum
429
Q

Somatic Layer of Hypomere

A

Forms the parietal, or somatic, peritoneum

- Lines the outer tube: somatopleure

430
Q

Visceral Layer of Hypomere

A

Forms the visceral, or sphlanchnic, peritoneum

- Covers the inner tube of the body: splanchnopleure

431
Q

Somatopleure

A

Formed from the somatic mesoderm and ectoderm

432
Q

Splanchnopleure

A

Formed from the splanchnic mesodern and endoderm

433
Q

Dorsal mesentery

A

Dorsal section of splanchnic peritoneum layers that divides the coelom into left and right halves

  • Persists in adults
  • Is used for passage of vessels and nerves to the gut

Several Derivatives

  • The Mesentery
  • Mesocolon
  • Mesorectum
  • Greater Omentum
434
Q

Ventral mesentery

A

Ventral section of splanchnic peritoneum layers that divides the coelom into left and right halves

  • Mostly disappears in adults so that the left and right coelomic cavities merge into a single cavity
  • Liver develops within it
435
Q

Pericardial Cavity

A

Anteroventral cavity within the coelom within which the heart develops
- Is initially open, but is eventually closed off by the transverse septum

436
Q

Transverse Septum

A

Septum that separates the pericardial cavity from the rest of the coelom
- Communication to the pleuroperitoneal cavity may persist through the pericardioperitoneal canal

437
Q

Pleuropericardial Membrane

A

Dorsal extension of the transverse septum in tetrapods

- Due to development of the neck pushing the pericardial cavity back

438
Q

Pleural Cavity

A

Cavity within which the lungs reside

- In mammals and many reptiles

439
Q

Peritoneal Cavity

A

Cavity within which the majority of the gut and urogenital system reside
- In mammals and many reptiles

440
Q

Pleuroperitoneal Cavity

A

Cavity within which the majority of the gut, lungs and urogenital system reside
- In basal tetrapods

441
Q

Pleuroperitoneal Membrane

A

Membrane that separates the peritoneal from the pleural cavity
- Not very well developed in birds

442
Q

Diaphragm

A

Muscular separation between the pleural and peritoneal cavities in mammals
- Formed from the pleuroperitoneal membrane

443
Q

Central Tendon

A

Feature of mammals

- Formed from the transverse septum

444
Q

Mesenteries

A

Formed from to apposed sheets of splanchnic hypomere and begin as dorsal and ventral

Function

  1. Secure the integrity of cavities
  2. Define spaces for the activity of organs
  3. Isolate organs from one another
445
Q

Liver

A

Large gland of the gut that is typically divided into lobes

  • Receives blood from the viscera and spleen before passing them to the heart
  • Retains connection to the gut via the hepatic duct
  • Forms as a ventral outgrowth of the gut that expands within the ventral mesentery; endodermal in origin
  • Expands within the transverse septum
  • Attachments: lesser omentum & falciform ligament
446
Q

Lesser Omentum

A

A.K.A. Gastrosplenic Ligament
Stretches between the gut and liver
- Is a continuation of the peritoneum that surround the digestive tract

447
Q

Falciform Ligament

A

Stretches between the liver and the ventral body wall

- Remnant of the ventral mesentery

448
Q

The Mesentery

A

The portion of the dorsal mesentery that supports the small intestine

449
Q

Mesocolon

A

The portion of the dorsal mesentery that supports the large intestine

450
Q

Mesorectum

A

The portion of the dorsal mesentery that supports the rectum

451
Q

Greater Omentum

A

A.K.A. Mesogaster

The portion of the dorsal mesentery that supports the stomach

452
Q

Omental Bursa

A

Extension of the dorsal mesentery that forms from the greater omentum and drapes ventrally over the viscera

  • Used largely in fat storage
  • Forms partly due to the rotation of the gut
  • Ends up being ventral in position but is still part of the dorsal mesentery
  • Contains the lesser peritoneal cavity
453
Q

Lesser Peritoneal Cavity

A

Space contained within the omental bursa

454
Q

Gastroepiploic Foramen

A

The entrance into the lesser peritoneal cavity

455
Q

Hepatic Duct

A

Carry bile from the liver to the common bile duct

456
Q

Cystict Duct

A

Carries bile from the gallbladder to the common bile duct

457
Q

Common Bile Duct

A

Carries bile from the hepatic and cystic ducts to the gut

458
Q

Gallbladder

A

Small organ off of the liver that stores a reserve of bile

- Forms as an outgrowth of the hepatic duct

459
Q

Functions of the Liver

A
  1. Stores and manufactures carbohydrates, proteins and fats for the body from materials absorbed by the intestine
  2. Produced red blood cells in early fetal stages
  3. Destroys old blood cells
  4. Detoxifies the blood
  5. Produces bile
460
Q

Bile

A

Portions waste products from destroyed blood cells and includes bile salts, which act as emulsifiers
- Critical for lipid digestion and absorption

461
Q

Pancreas

A

Gland that lies within the dorsal mesentary dorsal to the stomach and intestine

  • May not be present as a discrete gland
  • Begins as a dorsal and a ventral outgrowth of the intestine that are connected via the isthmus
  • Has one or more duct that leads to the duodenum
  • Both an endocrine and exocrine gland
462
Q

Exocrine Gland

A

A gland that excretes its essential product by way of a duct to some environment external to itself, either inside the body or on a surface of the body.

463
Q

Endocrine Gland

A

A gland that secretes its product without a duct either directly into the bloodstream or through diffusion

464
Q

Exocrine Functions of the Pancreas

A

Produces “pancreatic juice”

  • Mixture of various alkaline enzymes and proenzymes
  • Neutralizes acidic materials coming from the stomach
465
Q

Endocrine Functions of the Pancreas

A

Found in pancreatic islets scattered between the exocrine portion

  • Produce insulin and glucagon
  • Both important in controlling glucose blood levels
466
Q

Spleen

A

Major hemopoetic organ in the embryo of all vertebrates

  • Defends, stores and destroys blood corpuscules
  • Forms from the gut endoderm but is not part of the digestive system
  • Persists in most adults except in mammals, where bone marrow takes over the hemopoetic function
467
Q

Hemopoetic

A

Something that forms lood cells

468
Q

Cardiovascular System

A

Has four basic components

  1. Heart
  2. Arteries
  3. Veins
  4. Capillaries
469
Q

Heart

A

Muscular pump that receives blood at one end and pumps it out the other

  • Posterior portion becomes very muscular to function as a pump
  • Anterior part becomes the ventral aorta
  • Primitively a tube with four chambers that are arranged in sequential order and valves between them
  • Tends to fold into an S-shaped structure in primitive animals like the dogfish
  • Also four chambers in mammals and birds, but they are different
470
Q

Arteries

A

Vessels that conduct blood away from the heart and toward a capillary system
- NOT just oxygenated blood

471
Q

Veins

A

Vessels that bring blood toward the heart and away from a capillary system
- NOT just deoxygenated blood

Divided into four systems

  1. Subintestinal System
  2. Dorsal Cardinal Veins and Venae Cavae
  3. Abdominal Veins
  4. Pulmonary Veins
472
Q

Capillaries

A

System of tiny vessels that connect arteries and veins

- The area for blood exchange - arteries and veins are for transport

473
Q

Portal Veins

A

Vessels that collect blood from a capillary system and transports it to another
- Do not lead blood directly to or from the heart

474
Q

Functions of the Cardiovascular System

A
  • Transports materials to and from cells
  • Supplies nutrients like oxygen and glucose
  • Removes wastes like carbon dioxide, nitrogenous waste and excess water
  • Circulates hormones from the endocrine glands to aid in communication
  • Contributes to homeostasis by ensuring uniform composition of interstitial fluid and helping maintain uniform internal temperature
  • Helps maintain the immune system
  • Repairs injured tissue
475
Q

Blood Circulation in Gilled Animals

A
  1. Blood with low O2 goes to the gills from the heart to be oxygenated
  2. Oxygenated blood is distributed to the body
  3. Newly deoxygenated blood returns to the heart (via the liver if from the gut)
476
Q

Blood Circulation in Teatrpods

A
  1. Deoxygenated blood is sent from the heart to the lungs
  2. Newly oxygenated blood is returned to the heart
  3. This blood is distributed to the rest of the body
  4. Newly deoxygenated blood is returned to the heart (via the liver if from the gut)
477
Q

Subintestinal Veins

A

Veins that extend along the ventral surface of the gut

  • Paired initially, but soon become a single vein
  • First system of veins to arise in the embryo
  • Anterior part gives rise to the heart and ventral aorta and the posterior part extends from the gut to the heart
  • Later disrupted by the liver, so divides into hepatic vein and hepatic portal vein
478
Q

Hepatic Vein

A

Vein that stretches from the liver to the heart

  • Arises from the anterior part of the subintestinal vein after being disrupted by the liver
  • Becomes partially incorporated in the posterior vena cava in lungfish and tetrapods, so becomes part that stretches from PVC to liver
479
Q

Hepatic Portal Vein

A

Portal vein that stretches from the gut to the liver

480
Q

Dorsal Veins

A

A.K.A. Cardinal Veins
Veins that have paired anterior and posterior parts and collect into the common cardinal vein
- Remain unchanged in adult chondrichthyeans and actinopterygians

Includes

  • Anterior Cardinal Veins
  • Posterior Cardinal Veins
  • Common Cardinal Veins
  • Caudal Vein
481
Q

Common Cardinal Vein

A

Collects blood from the dorsal veins and carries it to the sinus venosus of the heart

  • Becomes continuous with anterior cardinal in lungfish and tetrapods due to the reduction of the posterior cardinal
  • Receives the subclavian in vertebrates above the chondrichthyeans
482
Q

Anterior Cardinal Veins

A

Paired veins that extend anteriorly from the heart on either side of the body
- Becomes continuous with the common cardinal in lungfish and tetrapods due to the reduction of the posterior cardinal

483
Q

Posterior Cardinal Veins

A

Paired veins that extend posteriorly from the heart on either side of the body

  • Becomes less important in lungfish and tetrapods
  • Posterior parts are lost in lower tetrapods, with the remaining part being the azygos
484
Q

Caudal Vein

A

Vein that extends from the tail region and splits into the posterior cardinal veins

485
Q

Renal Portal Vein

A

Veins that extend between the caudal vein and the kidneys

- Found in gnathostomes but not agnathans

486
Q

Lateral Head Vein

A

Main stem of each anterior cardinal vein in all tetrapods except mammals

  • Begins in the orbit and extends back along the lateral surface of the braincase and otic region
  • Receives tributaries from the brain
  • Eventually hooks up into the common cardinal
487
Q

Cranial Veins in Mammals

A
  • Lateral head vein lost due to development of inter-communicating sinuses in the cranial cavity (also in crocs and birds)
  • Blood enters cranial cavity and leaves posteriorly through the internal jugular vein
  • External jugular vein joins the internal jugular vein
  • Subclavian vein joins the internal and external jugular veins
  • Left anterior vena cava may be lost so that all blood enters the right anterior vena cava
488
Q

Anterior Vena Cava

A

Single remaining anterior cardinal vein in higher vertebrates

489
Q

Posterior Vena Cava

A

Single remaining posterior cardinal vein in higher vertebrates

  • Begins as a branch of the hepatic vein that grows upwards past the liver and taps into the right posterior cardinal
  • Becomes the main posterior venous system after the loss of the posterior cardinal veins
490
Q

Azygos Vein

A

Remnant of the posterior cardinal vein in lower tetrapods

- Initially both are present but the left becomes a hemiazygos with the loss of the left anterior vena cava

491
Q

Abdominal Veins

A

Primitively paired structures that extend along the ventrolateral body wall

  • Receives the subclavian and iliac veins in chondrichthyeans
  • Absent in actinopterygians
  • Single median vessel in lungfish, amphibians and reptiles that goes to the liver; technically part of the hepatic portal system
492
Q

Iliac Vein

A
  • Connects to both the abdominal vein and the renal portal vein in lungfish, amphibians and reptiles
  • Connects to the renal portal vein in actinopterygians and birds
  • Connects directly to the posterior vena cava in mammals
493
Q

Pulmonary Vein

A
  • Absent in most living fishes due to the absence of lungs
  • Empties into the hepatic vein and then the heart in fish with a functional lung; creates a mixture of oxygenated and deoxygenated blood to the heart
  • In lungfish and all higher vertebrates, bypasses the sinus venosus and enters the heart through the left side of the atrium
494
Q

Sinus Venosus

A

Posterior chamber of the heart in primitive vertebrates
Thin-walled sac that collects venous blood
- Incorporated into other structures of the heart or circulatory system in tetrapods

495
Q

Conus Arteriosus

A

Anterior chamber of the heart in primitive vertebrates
Muscular and elastic to ensure a steady flow of blood that is under high pressure as it leaves the ventricle
- Incorporated into other structures of the heart or circulatory system in tetrapods

496
Q

Lungfish Heart

A
  • Pulmonary vein does not enter the sinus venosus with other body veins, but enters directly through the left side of the atrium
  • Sinus venosus reduced or incorporated into the left ventricle
  • Partial septum between the left and right atria
  • Partial septumbetween the left and right ventricle
497
Q

Amphibian Heart

A
  • Complete septum between the left and right atria
  • Ancient species probably also had partial septum between left and right ventricles, but in modern amphibians it is undivided
  • Much oxygen exchange occurs through skin and blood returns to the right atrium
  • Pulmonary vein returns blood from the lungs to the left atrium
498
Q

Reptile Heart

A
  • One or two partial septa in the ventricle, with a gap still existing
  • Dorsal ventricle further subdivided, but incompletely
  • Both oxygenated and unoxygenated blood enter part of the dorsal ventricle
  • Although it would appear that is should receive some deoxygenated blood, the left systemic arch actually receives only oxygenated blood
  • Pulmonary arch receives deoxygenated blood from the right atrium
499
Q

Crocodile Heart

A
  • Ventricle is divided
  • Anatomically, the pulmonary arch and left systemic arch should receive venous blood from the right ventricle and the right systemic arch should receive oxygenated blood from the right ventricle
  • However, left systemic arch receives oxygenated blood (like it’s supposed to) through the foramen of Panniza
500
Q

Foramen of Panniza

A

Gap at the base of the arterial trunks in crocodilians that shunts blood from the left ventricle to the left systemic arch
- Can be closed in order to recycle deoxygenated blood while diving

501
Q

Mammal/Bird Heart

A
  • Ventricle is completely split
  • Only oxygenated blood enters the left ventricle to go to the body and head
  • Venous blood enters the right ventricle and goes to the lungs
  • Only one systemic arch: right in birds and left in mammals
502
Q

Lungfish & Amphibian Conus Arteriosus

A

Spiral valve develops in most of it, dividing it into two channels

  • Venous blood is directed mainly into one channel, while oxygenated blood goes into the other
  • Distally, venous blood goes to the pulmonary artery while oxygenated blood goes to the vessels of the head and body
503
Q

Amniote Conus Arteriosus

A

Considerably reduced and is usually incorporated into the ventricle or the arches that leave the heart

504
Q

Lymphatics

A

Secondary system of vessels that supplement the veins in returning fluids from tissues to the heart

  • Carry surplus fluids left in tissues
  • Vessels are closed an parallel the veins in many functions
  • Lack a direct connection to the arterial system
  • Low pressure within vessels, so fluid enters easily and movement of the fluid is slow and driven mainly by muscular action
  • Important in the gut, where they absorb many fats
505
Q

Lymph Hearts

A

Contractile structures along lymph vessels that actively pump fluid back into veins

506
Q

Lymphocytes

A

White blood cells

- Produced in lymph nodes in mammals

507
Q

Chyle

A

Fatty lymph

508
Q

Atrium

A

Thin-walled structure of the heart that receives blood from the sinus venosus and injects the proper amount of blood into the ventricle

509
Q

Ventricle

A

Large, muscular chamber of the heart that pumps blood to the body

510
Q

Aortic Arches

A

Arise in pairs from the ventral aorta and pass through the gill bars and into the dorsal aorta before continuing to the rest of the body

  • Breaks into a capillary system in each gill bar for gas exchange
  • Number of arches depends on the number of pharyngeal slits
  • Each arch is continuous in the embryo and is interrupted by capillary system as the gills develop
511
Q

Afferent Branchial Arteries

A

Arteries that carry blood from the ventral aorta to the capillary system of an aortic arch

512
Q

Efferent Branchial Arteries

A

Arteries that carry blood from the capillary system of an aortic arch to the dorsal aorta

513
Q

Ventral Aorta

A

Single, median vessel that that extends anteriorly from the heart

  • Usually bifurcates anteriorly
  • In terrestrial species, is usually bifurcated from the base into a trunk for the systemic arches and one for the pulmonary artery
514
Q

Dorsal Aorta

A

Single vessel posteriorly that bifurcates anteriorly into paired vessels over the gills

515
Q

Aortic Arch System of Sharks

A
  • Efferent branchial arches are shifted over each slit instead of over the middle of the gill bar
  • Aortic arches remain in same spot ventrally
  • External carotid artery extends down & forward from the efferent branchial artery
  • Arch 1 becomes the mandibular artery
  • Arch 2 becomes the hyoid artery
516
Q

External Carotid Artery

A

Extends from the first efferent branchial artery to supply oxygenated blood to the lower jaw
- In embryo, forms from the front end of the ventral aorta but needs to become associated with efferent system to carry oxygenated blood

517
Q

Mandibular Artery

A

Artery between the mouth and spiracle in jawed fishes

- Modified from aortic arch I

518
Q

Hyoid Artery

A

Artery between the spiracle and first regular pharyngeal slit in jawed fishes
- Modified from aortic arch II

519
Q

Afferent Spiracular Artery

A

Artery that supplies the spiracle in primitive fish

- Branch of the efferent branchial artery of aortic arch II, so blood is oxygenated

520
Q

Efferent Spiracular Artery

A

Artery that leaves the spiracle to help supply the brain and eye in sharks and some bony fish
- Modified from the efferent portion of aortic arch I

521
Q

Aortic Arch System of Most Bony Fishes inc. Lungfish

A
  • Aortic arch II is lost

- Only arches III-VI are present

522
Q

Pulmonary Artery

A

Artery leaving the lung

  • Developed in fish with lungs as a branch of aortic arch VI
  • Blood already oxygenated
523
Q

Aortic Arch System of Tetrapods

A
  • Aortic arches are never split into afferent and efferent portions, so remain as continuous tubes
  • AAs may be interrupted in juveniles with functional gills but are restored in adult
524
Q

Aortic Arch System of Adult Amphibians

A
  • At least three aortic arches are present: III, IV & VI
  • Arch V is absent in frogs and amniotes, but may be present in urodeles and embryos as a small, transient tube
  • Dorsal connection between arches III and IV become smaller and tend to disappear
525
Q

Ductus Arteriosus

A

Narrow vessel dorsal to the pulmonary artery in aortic arch VI

  • Usually disappears in tetrapods that have functional lungs
  • Persists in gymnophionans and urodeles as well as some reptiles
526
Q

Carotid Duct

A

Narrow vessel connecting the dorsal portions of aortic arches III & IV
- Found in gymnophionans as well as some urodeles and reptiles

527
Q

Internal Carotid Artery

A

Artery that supplies blood to the head

- Formed from aortic arch III (AA II in sharks) and the associated anterior part of the dorsal aorta

528
Q

Common Carotid Artery

A

Forms from the ventral aorta that leads to aortic arch III

529
Q

External Carotid Artery

A

Anterior and inferior continuation of the common carotid artery
- Enlarges and extends dorsally in mammals to take over the functions of the stapedial

530
Q

Systemic Arches

A

Main supply of blood to the body from the heart

- Formed from aortic arch IV

531
Q

Trunks of the Heart in Reptiles

A

Three separate trunks

  1. Pulmonary trunk
  2. Left systemic artery (left AA IV)
  3. Right systemic artery (right AA IV)

*Carotid arteries and arteries of the forelegs are associated with the right systemic artery

532
Q

Trunks of the Heart in Birds

A

The left systemic artery has been lost, so only the pulmonary trunk and right systemic artery leave the heart

533
Q

Trunks of the Heart in Mammals

A

Right systemic artery has been lost, so only the pulmonary trunk and left systemic artery leave the heart

  • Probably never passed through the 3-trunk stage of reptiles
  • Arch system of ancestral mammals was probably similar to that of frogs
  • Carotids on right side established connection with the left aortic arch IV
  • Base of the right aortic arch IV remains as a connection woth the subclavian artery
534
Q

Orbital Artery

A

A.K.A. Stapedial Artery (in tetrapods, orbital in shark)
Artery that supplies the superficial parts of the head and lower jaw
- Connects with the efferent spiracular artery
- Arises from the internal carotid artery just before it enters the braincase
- Reduced or absent in mammals; functions taken over by external carotid artery

535
Q

Urogenital System

A

System that includes organs used for excretion and reproduction
- Primary organs for both functions develop next to each other in the embryo and some of their accessory organs are entangled

536
Q

Kidney

A

The major excretory organ of all vertebrates

  • Rids the body of nitrogenous waste
  • Plays a major role in water balance
  • Associated terminology based initially on amniotes and becomes quite complex
537
Q

Holonephros

A

The idealized, primitive kidney

  • Develop from the mesomere of the mesodermal somites
  • Doesn’t exist but is approached closely in the larvae of cyclostomes and gymnophionans
  • Consists of a series of nephric units and an archinephric duct
538
Q

Nephric Units

A

A.K.A. tubules
The somites of the mesomere/nephrotome
- Develop as tubules with one per body segment
- Develop from front to back

539
Q

Longitudinal Duct

A

Duct of the urogenital system that developes from the first few nephric units in the holonephros
- Extends back to the developing cloaca

540
Q

Archinephric Duct

A

A.K.A. wolffian duct
Duct of the urogenital system that forms when the somewhat more posterior nephric tubules join the longitudinal duct
- Duct still begins at the anterior end of the system
- Used primarily form sperm conduction in most vertebrates, but retained for urine use in cyclostomes/bony fishes
- Usually degenerates in females

541
Q

Pronephros

A

Anterior part of the primitive kidney in which the anteriormost tubules become specialized or degenerate

  • Still develops the archinephric duct
  • Found in adult hagfish and all higher vertebrates
542
Q

Opisthonephros

A

The posterior part of the kidney in adult, jawed anamniotes

  • Has an increased number of tubules
  • Kidney is usually concentrated posteriorly in a small segment
  • Segmentation is lost
  • Anterior part is typically associated with the testes, meaning the archinephric duct is used for sperm passage
543
Q

Mesonephros

A

The anterior part of the kidney for a considerable amount of embryonic development in amniotes

  • Also the name usually used for the adult kidney in anamniotes, but they are not the same developmentally
  • Serves as the functional kidney in embryo but loses its urinary function, as does the archinephric duct, by birth
  • Does not include the most posterior part of nephric tissue
544
Q

Metanephros

A

Posterior portion of the kidney in amniotes

  • An unsegmented, essentially spherical mass that eventually develops a large number of tubules
  • This is the kidney of the late embryo & adult
545
Q

Ureter

A

Duct that drains the tubules of the metanephros

- Develops from back to front and before the metanephros tubules; may even induce their formation

546
Q

Anamniote Kidney

A

Called the mesonephros, but develops from the entire holonephros minus the pronephros
- Typically drained by the archinephric duct, but accessory urinary ducts may develop

547
Q

Gonadial Ducts

A

Ducts responsible for the transport of gametes

- Primitively, none actually existed and gametes were shed directly into the coelom

548
Q

Gonadial Ducts in Cyclostomes

A

None!

- Sperm & ova shed directly into the coelom and find way to cloaca through abdominal pores

549
Q

Gonadial Ducts in Gnathostomes

A

Usually have closed tubes

  • Ova usually shed into coelom and taken up by open nearby duct
  • Exception is teleosts, where vary and duct are enclosed becausethey produce massve amounts of eggs
550
Q

Ovarian Duct

A

A.K.A. Mullerian Duct

  • Eventually forms the uterine tube and uterus
  • Tends to be funnel-shaped at the end to facilitate uptake of ova
  • Usually forms from infolding of the coelomic epithelium near the archinephric duct; also splitting of the AD in others
551
Q

Testis

A

Male gonad

  • Develops anteriorly in the coelom, near the anterior part of the kidney
  • Since semeniferous tubules lie close to the tubules of the kidneys, the testes can co-opt the archinephric duct for sperm condution
552
Q

Vas Deferens

A

Name for the archinephric duct when used solely for sperm passage

553
Q

Cyclostome Urogenital Ducts

A
  • Archinephric duct used for urine by kidney

- No ducts developed for use by testes or ovaries

554
Q

Teleost Urogenital Ducts

A
  • Archinepric duct used by kidney for urine
  • Testes develop their own duct for sperm
  • Ovarian duct developed for ova
555
Q

Anamniote Urogenital Ducts

A

Males

  • Archinephric duct used for sperm conduction
  • Urine uses accessory ducts to pass to cloaca or end of archinephric duct

Females

  • Archinephric duct used for urine
  • Ovarian duct used for passage of ova
556
Q

Amniote Urogenital Ducts

A
  • Archinephric duct used for sperm conduction as vas deferens in males; degenerates in females
  • Ureter used for urine
  • Ova pass through oviduct in females
557
Q

Nervous System

A

Sensory system that develops very early on in vertebrate embryos

Two kinds

  • Central Nervous System
  • Peripheral Nervous System
558
Q

Central Nervous System

A

Nervous system that consists of the neural tube

  • Brain and spinal cord
  • Forms from the neurectoderm by rolling of the tissue along the middorsal line
  • Is a continuous structure with enlarged development at the anterior end forming the brain and the remainder being the spinal cord
559
Q

Peripheral Nervous System

A

Nervous system that consists of motor and sensory neurons

  • Nerves stem from the central nervous system
  • Motor neurons developed from the central nervous system
  • Sensory neurons developed from neural crest

Four types of nerve fibres

  • Somatic sensory
  • Somatic motor
  • Visceral sensory
  • Visceral motor
560
Q

Peripheral Nerves

A

Nerves of the peripheral nervous system

- Made of fibres, i.e. axons of neurons

561
Q

Cell Body

A

Component of a nerve that is present either in the spinal cord or a ganglion

562
Q

Ganglia

A

Swellings that contain clusters of cell bodies

- Part of the peripheral nervous system

563
Q

Axon

A

The long extesio of a neuron

564
Q

Reflex Arc

A

Simple neural pathway containing with only two or three neurons involved
- Contains a sensory and a motor neuron with a possible inter-neuron betwee the two

565
Q

Sensory Neuron

A

A.K.A. Afferent neuron
A neuron that carries information from the body (or outside it) to the brain/central nervous system
- Information received at a receptor and carried to a synapse

566
Q

Motor Neuron

A

A.K.A. Efferent neuron
A neuron that carries signals away from the brain/central nervous system
- Signal is received at the synapse and carried to an effector
- Cause actions, like the movement of a muscle

567
Q

Inter-neuron

A

A.K.A. association neurons
A neuron that carries signals between other neurons
- Most neurons in the nervous system

568
Q

Somatic Sensory Nerves

A

Nerves that carry signals from the skin and the sense organs of muscles and tendons toward the brain

569
Q

Somatic Motor Nerves

A

Nerves that carry signals from the brain to the somatic (mainly skeletal) musculature

570
Q

Visceral Sensory Nerves

A

Nerves that carry signals from the gut to the brain

571
Q

Visceral Motor Nerves

A

Nerves that carry signals from the brain to the gut muscles, blood vessels and glands

Two subdivisions

  • Autonomic
  • Special Branchial
572
Q

Autonomic Nerves

A

Involuntary, visceral motor nerves associated with the gut

Two types

  • Parasympathetic
  • Sympathetic
573
Q

Special Branchial Nerves

A

Visceral motor nerves associated with the head and branchial arches
- Specialized striated musculature of the visceral skeleton

574
Q

Spinal Nerves

A

Nerves extending from the spinal cord that are usually paired and present in every body segment

  • Carries multiple types of nerve fibre in the main trunk
  • Each is formed from a dorsal and a ventral root that usually unite to form the main trunk of the spinal nerv within the vertebral canal
  • Divide into branches/rami soon after leaving the vertebral canal
  • Somatic and visceral fibres need to cross over one another as the nerve divides
575
Q

Dorsal Root (Higher Vertebrates)

A

Spinal nerve root on the dorsal side of the spinal cord that gives rise to sensory nerve fibres

576
Q

Ventral Root (Higher Vertebrates)

A

Spinal nerve root on the ventral side of the spinal cord that gives rise to motor nerve fibres

577
Q

Spinal Nerve Roots in Lower Vertebrates

A
  • Limited connection between the two in sharks and hagfishes
  • Do not fuse in amphioxus and lampreys and come off sequentially

Dorsal Root

  • Somatic sensory
  • Visceral sensory
  • Visceral motor

Ventral Root

  • Somatic motor
  • Visceral motor
578
Q

Spinal Nerve Roots in Amphioxus

A
  • Ventral and dorsal roots alternate, so do not arise one above the other
  • Dorsal roots are intersegmental

Dorsal Root

  • Somatic sensory
  • Visceral sensory
  • Visceral motor

Ventral Root
- Somatic motor

579
Q

Tripartite Brain

A

Brain consisting of three primary parts that is characteristic of vertebrates

  • Later specialization produces the five parts we’re familar with
  • Sections defined by two flexures of the neural tube that occur during development
  • First flexure: downward
  • Second flexure: dorsal
580
Q

Prosencephalon

A

Anterior part of the tripartite brain

  • Defined posteriorly by a downward flexure
  • Initially associated with nasal function
  • Gives rise to the telencephalon and diencephalon
581
Q

Mesencephalon

A

Middle part of the tripartite brain

  • Defined anteriorly by a downward flexure and posteriorly by a dorsal flexure
  • Contains the optic ventricle
  • Initially associated with eye function, but this is lost in higher amniotes
  • Roof (tectum) enlarges in later forms
  • Contains the optic lobes in many lower vertebrates
582
Q

Rhombencephalon

A

Postrior part of the tripartite brain

  • Defined anteriorly by a dorsal flexure and continues posteriorly as the spinal cord
  • Initially associated with the ear and lateral line
583
Q

Brain Stem

A

Brain as defined by the prosencephalon, mesencephalon and rhombencephalon

  • Controls numerous vital functions
  • Phylogenetically and embryoloically the oldest part of the brain
  • Other parts of the brain are dorsal outgrowths of this
584
Q

Telencephalon

A

Anterior part of the five-part brain

  • Consists of paired cerebral hemispheres and olfactory bulbs
  • Contains lateral ventricles in each cerebral hemisphere
  • Primitively, main function was smell, but cerebrum takes over the function of sight in mammals, birds and some other reptiles
  • Formed from the anterior part of the prosencephalon
585
Q

Diecephalon

A

Second part of the five-part brain

  • Consists of the thalamus, epithalamus and hypothalamus
  • Contains the third ventricle
  • Formed from the prosencephalon
586
Q

Metencephalon

A

Fourth part of the five-part brain

  • Consists of the cerebellum (and the pons in mammals)
  • Contains the cerebellar ventricle
  • Primitively, main function is hearing, balance and equilibrium
  • Formed from the anterior part of the rhombencephalon
587
Q

Myelencephalon

A

Posterior part of the five-part brain

  • Consists mainly of the medulla oblongata
  • Contains the fourth ventricle
  • Formed from the posterior part of the rhombencephalon
588
Q

Ventricles of the Brain

A

Spaces within the brain that are extensions of the dorsal hollow nerve cord

  1. Lateral ventricles (2)
  2. Third ventricle
  3. Optic ventricle
  4. Cerebellar ventricle
  5. Fourth ventricle
589
Q

Lateral Ventricles

A

Paired ventricles found in the cerebral hemispheres of the telencephalon

590
Q

Third ventricle

A

Ventricle found in the diencephalon

591
Q

Optic ventricle

A

Ventricle found in the mesencephalon

- Lost in mammals and birds

592
Q

Cerebellar Ventricle

A

Ventricle found in the metencephalon

- Becomes an extension of the fourth ventricle in higher vertebrates

593
Q

Fourth Ventricle

A

Ventricle found in the myelencephalon

594
Q

Cranial Nerves

A

Nerves that arise from the brain

  • Thirteen in total, with 12 designated by roman numerals; each also has a name
  • Can make sense of them by considering segmentation: while the head may not necessarily have been segmented originally, looking at it this way help make sense of things
Names:
O. Terminalis
I. Olfactory
II. Optic
III. Oculomotor
IV. Trochlear
V. Profundus, Trigeminal proper
VI. Abducens
VII. Facial
VIII. Acoustic
IX. Glossopharyngeal
X & XI. Vagus & accessory
XII. Hypoglossal
595
Q

Special Visceral Sensory Nerves

A

Nerves of the taste organs

596
Q

Special Somatic Sensory Nerves

A

Nerves for the somatic sensory structures, including the nose, eyes ears and lateral line

597
Q

Basic Types of Cranial Nerves

A
  1. Special Sensory Nerves
    - Special somatic sensory nerves
  2. Dorsal Root OR Branchial Nerves
    - Somatic sensory
    - Visceral sensory including general and special
    - Visceral motor including autonomic and special branchial
  3. Ventral Root Nerves
    - Mostly somatic motor
598
Q

Terminalis Nerve

A

Cranial Nerve 0

- Dorsal Root, somatic sensory nerve

599
Q

Olfactory Nerve

A

Cranial Nerve I

- Special somatic sensory nerve

600
Q

Optic Nerve

A

Cranial Nerve II

- Special somatic sensory nerve

601
Q

Oculomotor Nerve

A

Cranial Nerve III

  • Ventral Root, somatic motor nerve
  • Develops in first preotic somite
  • Splits into ventral oblique; dorsal, ventral and medial rectus
602
Q

Trochlear Nerve

A

Cranial Nerve IV

  • Ventral Root, somatic motor nerve
  • Develops in second preotic somite
  • Enters the dorsal oblique
603
Q

Profundus Nerve

A

Cranial Nerve V(1)

- Dorsal Root, somatic sensory and visceral motor nerves

604
Q

Trigeminal Nerve proper

A

Cranial Nerve V(2,3)

  • Nerve of the mandibular arch
  • Dorsal Root, somatic sensory and special visceral motor nerves
605
Q

Abducens Nerve

A

Cranial Nerve VI

  • Ventral Root, somatic motor nerve
  • Develops in third preotic somite
  • Enters the lateral rectus
606
Q

Facial Nerve

A

Cranial Nerve VII

  • Nerve of the hyoid arch
  • Dorsal Root: all types of nerves except somatic motor nerves
607
Q

Acoustic Nerve

A

Cranial Nerve VIII
A.K.A. Auditory nerve
- Special somatic sensory nerve: statoaccoustical and vestibulotrochlear (acoustic components)

608
Q

Glossopharyngeal Nerve

A

Cranial Nerve IX

  • Nerve of the first branchial arch
  • Dorsal Root: all types of nerves except somatic motor nerves
609
Q

Vagus Nerve

A

Cranial Nerve X & XI (Accessory)

  • Nerves of the remaining four branchial arches; usually has four branches that may have separate roots
  • Dorsal Root: all types of nerves except somatic motor nerves
610
Q

Hypoglossal Nerve

A 
Cranial Nerve XII
A.K.A. Hypobranchial nerve
- Ventral Root, somatic motor nerve
- Formed from the postotic somites
- Innervates the hypobranchial musculature and follows them when they migrate
611
Q

Lateral Line Nerves

A

Usually two sets, both anterior and posterior

  • Special somatic sensory nerves
  • Usually enter the braincase alongside some branchial nerves, but are different
612
Q

Major Modifications Occurring in the Head

A
  • Branchial region introduced and enlarged
  • Special sensory organs arose
  • Mouth enlarged
  • Brain enlarged
613
Q

Ventral Root Nerves

A

Primitively somatic motor nerves only, which innervate somatic muscles
- Since somatic muscles are derived from the myotomes of somites, which are segmented, these nerves are also segmented and align with somites

EEB263 (6 decks)

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