Final Exam

Question 1

Sagittal

Answer 1

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

Question 2

Midsagittal

Answer 2

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

Question 3

Parasagittal

Answer 3

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

Question 4

Transverse

Answer 4

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

Question 5

Frontal (section)

Answer 5

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

Question 6

Anterior

Answer 6

Towards the head

Question 7

Posterior

Answer 7

Towards the tail

Question 8

Dorsal

Answer 8

Towards the back

Question 9

Ventral

Answer 9

Towards the belly/substrate

Question 10

Medial

Answer 10

Towards the sagittal midline

Question 11

Lateral

Answer 11

Away from the sagittal midline

Question 12

Proximal

Answer 12

Closer to the point of reference

Question 13

Distal

Answer 13

Farther from the point of reference

Question 14

Craniata

Answer 14

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

Question 15

Pharyngotremata

Answer 15

Clade formed of the chordates and hemichordates

Question 16

Chordata

Answer 16

Clade that contains the craniates, urochordates and cephalochordates

Question 17

Protochordates

Answer 17

Group that includes everything EXCEPT the chordates

• i.e. hemichordates
• Not a natural grouping

Question 18

Important Chordate Characters

Answer 18

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

Question 19

Notochord

Answer 19

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

Question 20

Hemichordata

Answer 20

Sister group to Chordata
Two clades
- Enteropneusta
- Pterobranchia

Question 21

Pterobranchia

Answer 21

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

Question 22

Enteropneusta

Answer 22

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

Question 23

Endostyle

Answer 23

Mid-ventral groove that secretes mucus

Question 24

Urochordata

Answer 24

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

Question 25

Cephalochordata

Answer 25

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

Question 26

Heterochrony

Answer 26

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

Question 27

Paedomorphosis

Answer 27

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

Question 28

Craniata

Answer 28

Clade within Chordata | - Refers to chordates that have a well-defined "head" and a hard skull

Question 29

Agnathans

Answer 29

Craniates that lack jaws - Also lack paired appendages - Only extant species are the cyclostomes, used to also include ostracoderms

Question 30

Ostracoderms

Answer 30

Extinct, armoured agnathans - Covered by bony plates - Jawless

Question 31

Cyclostomes

Answer 31

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

Question 32

Petromyzontoidea

Answer 32

Lampreys - Predatory, parasitic - Oral cup attaches to prey, allowing them to drink blood and other body fluids

Question 33

Myxinoidea

Answer 33

Hagfish - Scavengers - Use horny tongue to rasp flesh from dead or dying prey

Question 34

Denticles

Answer 34

The keratinous teeth of cyclostomes

Question 35

Gnathostomata

Answer 35

True, jawed fishes | - Includes the placoderms and eugnathostomes

Question 36

Placodermi

Answer 36

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

Question 37

Eugnathostomata

Answer 37

"True jawed vertebrates" - Jaw made from visceral structures, either bone or cartilage Two major groups: - Chondrichthyes - Teleostomi

Question 38

Chondrichthyes

Answer 38

``` 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

Question 39

Elasmobranchii

Answer 39

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

Question 40

Holocephalia

Answer 40

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

Question 41

Stages leading to the typical vertebrate condition

Answer 41

1. Prevertebrate stage 2. Agnathan stage 3. Gnathostome stage

Question 42

Prevertebrate Stage

Answer 42

Urochordates, cephalochordates - Suspension feeders (cilia-mucus) - Small, poor swimmers - Ciliary action produces movement of water

Question 43

Agnathan Stage

Answer 43

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

Question 44

Gnathostome Stage

Answer 44

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

Question 45

Higher Fishes

Answer 45

Term that is usually used to refer to Osteichthyes

Question 46

Osteichthyes

Answer 46

"Bony fishes" - Bony skeleton is retained and enhanced - Most successful vertebrates in terms of diversity and numbers Groups: - Actinopterygii - Sarcopterygii

Question 47

Teleostomi

Answer 47

Clade that includes Acanthodii and Osteichthyes

Question 48

Acanthodii

Answer 48

``` 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 ```

Question 49

Actinopterygii

Answer 49

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

Question 50

Sarcopterygii

Answer 50

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

Question 51

Dipnoi

Answer 51

Lungfishes

Question 52

Coelecanth

Answer 52

"Latimeria"

Question 53

Chondrostei

Answer 53

Early, primitive actinopterygians - Few extant species, inc. sturgeons - Hyomandibular slopes backward - Long jaw - Maxilla involved in biting - Heterocercal tail

Question 54

Holostei

Answer 54

``` 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 ```

Question 55

Teleostei

Answer 55

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

Question 56

Trends in Actinopterygian Body shape and fin form

Answer 56

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

Question 57

Heterocercal

Answer 57

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

Question 58

Homocercal

Answer 58

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

Question 59

Diphycercal

Answer 59

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

Question 60

Tetrapoda

Answer 60

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

Question 61

Stegocephalia

Answer 61

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

Question 62

Elpistostegids

Answer 62

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

Question 63

Amphibia

Answer 63

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

Question 64

Amniota

Answer 64

More derived tetrapods - Lay amniotic eggs Two major lineages - Reptilia - Synapsida

Question 65

Amniotic Egg

Answer 65

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

Question 66

Lissamphibia

Answer 66

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)

Question 67

Anapsid

Answer 67

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

Question 68

Euryapsid

Answer 68

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

Question 69

Diapsid

Answer 69

Skull type in which there are two temporal fenestrae | - Most common form

Question 70

Synapsid

Answer 70

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

Question 71

Reptilia

Answer 71

Diverse lineage of tetrapods including lizards, birds, dinosaurs, etc. Two main groups - Parareptilia - Diapsida

Question 72

Parareptilia

Answer 72

Reptiles with anapsid skulls | - Inc. Testudines

Question 73

Testudines

Answer 73

Turtles

Question 74

Diapsida

Answer 74

Large, diverse group of reptiles - Diapsid and euryapsid skull - Diverse even by standards of all of Tetrapoda Two main groups - Archosauromorphia - Lepidosauromorphia

Question 75

Archosauromorphia

Answer 75

Includes: - Crocodiles - Pterosaurs - Dinosaurs (inc. birds)

Question 76

Lepidosauromorphia

Answer 76

Includes: - Ichthyosaurs - Plesiosaurs - Rhynchocephalians - Lizards (inc. snakes)

Question 77

Synapsida

Answer 77

One of the major clades within Amniota - Includes Mammalia and their fossil relatives - Characterized by synapsid skull type Two broad groups - Pelycosaurs - Therapsida

Question 78

Pelycosaurs

Answer 78

Early, basal group of synapsids | - Not a natural group

Question 79

Therpasida

Answer 79

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

Question 80

Mammal-like Reptiles

Answer 80

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

Question 81

Mammalia

Answer 81

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)

Question 82

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

Answer 82

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

Question 83

Tribosphenic Molar

Answer 83

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

Question 84

Bunodont Molar

Answer 84

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

Question 85

Monotremata

Answer 85

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

Question 86

Marsupialia

Answer 86

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

Question 87

Eutheria

Answer 87

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

Question 88

Chorioallantoic Placenta

Answer 88

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

Question 89

Embryology

Answer 89

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

Question 90

Early embryological processes

Answer 90

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

Question 91

Microlecithal

Answer 91

Egg type in which there is little yolk - E.g. in amphioxus - Blastula is one cell thick

Question 92

Mesolecithal

Answer 92

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

Question 93

Macrolecithal

Answer 93

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

Question 94

Yolk

Answer 94

Food material that is inert to an egg

Question 95

Vegetal Pole

Answer 95

End of an egg towards which the yolk gravitates | - Lower hemisphere of the egg

Question 96

Animal Pole

Answer 96

End of an egg that is less yolky

Question 97

Early divisions of an egg cell

Answer 97

Occurs in the protoplasm of an egg 1. Vertical 2. Vertical 3. Horizontal

Question 98

Blastula

Answer 98

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

Question 99

Blastocoele

Answer 99

Central cavity found within a blastula | - Separates blastula from yolk in macrolecithal eggs

Question 100

Mammalian Embryo Development

Answer 100

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

Question 101

Trophoblast

Answer 101

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

Question 102

Inner Cell Mass

Answer 102

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

Question 103

Primary Germ Layers

Answer 103

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

Question 104

Gastrula

Answer 104

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

Question 105

Gastrocoele

Answer 105

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

Question 106

Blastopore

Answer 106

Entrance into the gastrocoele

Question 107

Ectoderm

Answer 107

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

Question 108

Mesoderm

Answer 108

Germ layer between the ectoderm and endoderm - Becomes the somatic skeleton, muscle and circulatory system Two kinds - Chordamesoderm - Lateral mesoderm

Question 109

Endoderm

Answer 109

Germ layer formed from the vegetal pole of an egg | - Becomes the digestive tract, visceral muscles and visceral skeleton

Question 110

Neurectoderm

Answer 110

Forms from the dorsal middle of the ectoderm

Question 111

Chordamesoderm

Answer 111

Portion of the mesoderm that becomes the notochord

Question 112

Lateral Mesoderm

Answer 112

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

Question 113

Development of the Ectoderm

Answer 113

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

Question 114

Development of the Mesoderm

Answer 114

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

Question 115

Development of the Endoderm

Answer 115

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

Question 116

Neural Crest Cells

Answer 116

**In notes

Question 117

Neurogenic Placodes

Answer 117

**In notes

Question 118

Epimere

Answer 118

Dorsal subdivision of the lateral mesoderm

Question 119

Mesomere

Answer 119

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

Question 120

Hypomere

Answer 120

Ventral subdivision of the lateral mesoderm

Question 121

Development of the Epimere

Answer 121

1. Subdivides lateromedially into the dermatome, myotome and sclerotome

Question 122

Dermatome

Answer 122

Lateral subdivision of the epimere

Question 123

Myotome

Answer 123

Middle subdivision of the epimere

Question 124

Sclerotome

Answer 124

Medial subdivision of the epimere

Question 125

Development of the Hypomere

Answer 125

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

Question 126

Development of the Dermatome

Answer 126

1. Expands deep to the ectoderm | 2. Loses segmentation

Question 127

Development of the Myotome

Answer 127

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

Question 128

Development of the Sclerotome

Answer 128

1. Surrounds the notochord and the neural tube

Question 129

Structures formed from the Ectoderm

Answer 129

- 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

Question 130

Structures formed from the Dermatome

Answer 130

- Dermis of the integument - Dermal muscles - Dermal skeletal structures

Question 131

Structures formed from the Myotome

Answer 131

- Skeletal muscles: epaxial and hypaxial | - Appendicular skeleton

Question 132

Structures formed from the Sclerotome

Answer 132

Vertebral column

Question 133

Structures formed from the Visceral Hypomere

Answer 133

- Visceral serosa, including mesenteries - Visceral musculature - Heart - Blood vessels - Lymph vessels - Gonads

Question 134

Structures formed from the Somatic Hypomere

Answer 134

Parietal serosa

Question 135

Structures formed from the Endoderm

Answer 135

- Liver - Pancreas - Lining of the lungs - Digestive tract - Urinary bladder

Question 136

Integument

Answer 136

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

Question 137

Primary Body Tissues

Answer 137

- Epithelial - Connective - Muscular - Nervous

Question 138

Epithelial Tissue

Answer 138

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

Question 139

Serosa

Answer 139

Epithelial tissue that is internal and has no exit - Thoracic: pleura - Abdominal: peritoneum - Blood vessels: endothelium

Question 140

Mucosa

Answer 140

Epithelial tissue in structures that have an exit - Respiratory tract - Digestive tract

Question 141

Epidermis

Answer 141

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

Question 142

Dermis

Answer 142

Deep, connective tissue layer of integument - Formed mainly from the dermatome - Usually relatively thick - Vascularized - Has nervous structures in the form of sensory receptors

Question 143

Issues with (Semi)Permeable Skin

Answer 143

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

Question 144

"Water-Proofing" Skin

Answer 144

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

Question 145

Hypodermis

Answer 145

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

Question 146

Stratum Corneum

Answer 146

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

Question 147

Stratum Basale

Answer 147

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

Question 148

Integument in Fishes

Answer 148

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

Question 149

Integument in Derived Fishes

Answer 149

Scales usually present - Scales formed from the epidermis and dermis - May include enamel (epidermal), dentin (dermal) and bone (dermal)

Question 150

Placoid Scales

Answer 150

Type of scale seen in sharks - Scale is formed from dentin and projects through the epidermis - Capped by enamel - No dermal bone

Question 151

Dermal Bone in Fish

Answer 151

- 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

Question 152

Bony Fish Scales

Answer 152

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

Question 153

Integument in Amphibians

Answer 153

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

Question 154

Integument in Reptiles

Answer 154

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

Question 155

Reptilian Scales

Answer 155

- Usually lack underlying bony dermal contribution - Form from a fold in the surface epidermis - Can be modified into crests, spines and "horns"

Question 156

Osteoderm

Answer 156

Small piece of dermal bone found under epidermal scales | - Found in some turtle shell bones, crocodilians, some lizards and extinct reptiles

Question 157

Gastralia

Answer 157

Collection of dermal bone in the abdominal region

Question 158

Epidermal Derivatives

Answer 158

- Scales - Calluses - Nails - Claws - Hooves - Hair - Feathers - Baleen - Horns - Antlers - Glands

Question 159

Nails, Claws and Hooves

Answer 159

Keratinized epidermal structures that tip the digits of amniotes - Protective - Functional in climbing, defence, food gathering, etc.

Question 160

Horns and Antlers

Answer 160

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

Question 161

Hair

Answer 161

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

Question 162

Arrector Pili

Answer 162

Muscle associated with a hair follicle

Question 163

Sebaceous Gland

Answer 163

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

Question 164

Apocrine Gland

Answer 164

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

Question 165

Glands

Answer 165

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

Question 166

Uropygial Gland

Answer 166

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

Question 167

Salt Gland

Answer 167

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

Question 168

Eccrine Gland

Answer 168

Gland that secretes salt, urea or water

Question 169

Mammary Gland

Answer 169

Modified apocrine gland used to secrete milk

Question 170

Scent Gland

Answer 170

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

Question 171

Skeleton

Answer 171

Supportive structure that is composed of various kinds of connective tissue

Question 172

Connective Tissue

Answer 172

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

Question 173

Mesenchyme

Answer 173

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

Question 174

Bone

Answer 174

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

Question 175

Cartilage

Answer 175

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

Question 176

Bone vs Cartilage

Answer 176

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

Question 177

Parts of the Skeleton

Answer 177

Components that vary in structure, position and embryologic origin Three broad classes - Dermal skeleton - Endoskeleton - Heterotopic skeletal elements

Question 178

Dermal Skeleton

Answer 178

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

Question 179

Endoskeleton

Answer 179

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

Question 180

Somatic Skeleton

Answer 180

Skeleton from the outer tube of the body that is formed by somites Two types: - Axial - Appendicular

Question 181

Axial Skeleton

Answer 181

Most of the skull, vertebral column and axial ribs

Question 182

Appendicular Skeleton

Answer 182

Paired appendages and limb girdles

Question 183

Visceral Skeleton

Answer 183

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

Question 184

Heterotopic Skeletal Elements

Answer 184

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

Question 185

Diaphysis

Answer 185

Shaft of a long bone

Question 186

Epiphysis

Answer 186

End of a long bone

Question 187

Epiphyseal Line

Answer 187

Line that separates the diaphysis and epiphysis | - Formed from fusion of the epiphyseal plate

Question 188

Epiphyseal Plate

Answer 188

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

Question 189

Periosteum

Answer 189

Fibrous connective tissue that surrounds a bone | - Has a deep, bone-forming layer

Question 190

Medullary Cavity

Answer 190

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

Question 191

Endosteum

Answer 191

Connective tissue lining the medullary cavity and spaces within a bone

Question 192

Articular Cartilage

Answer 192

Cartilage found at the joints of bones

Question 193

Development of Endochondral Bone

Answer 193

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

Question 194

Postcranial Skeleton

Answer 194

All skeletal structures of the body not including the head - Largely formed by somatic endoskeletal elements - Axial and appendicular - Mesodermal in embryological origin

Question 195

Vertebral Column

Answer 195

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

Question 196

Dorsal Rib

Answer 196

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

Question 197

Ventral Rib

Answer 197

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

Question 198

Vertebrae

Answer 198

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

Question 199

Amphicoelous

Answer 199

Type of vertebra where the centrum is concave at both ends | - Typical of fishes and early tetrapods

Question 200

Procoelous

Answer 200

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

Question 201

Opithocoelous

Answer 201

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

Question 202

Acoelous

Answer 202

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

Question 203

Heterocoelous

Answer 203

Type of vertebra where the centrum is saddle shaped | - Typical of the neck vertebrae of birds

Question 204

Evolution of Vertebrae

Answer 204

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

Question 205

Embryologic Development of Vertebrae

Answer 205

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

Question 206

Appendicular Skeleton of Fish vs Tetrapods

Answer 206

Fish - Relatively simple and small - Pectoral > Pelvic Tetrapods - Large and more complex; needed to keep body off ground and propel it - Pelvic > Pectoral

Question 207

Pectoral Girdle of Bony Fish

Answer 207

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

Question 208

Pectoral Girdle of Tetrapods

Answer 208

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

Question 209

Pelvic Girdle of Fish

Answer 209

Relatively small and is not attached to the body/vertebrae

Question 210

Pelvic Girdle of Tetrapods

Answer 210

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

Question 211

Evolution of Posture in Tetrapods

Answer 211

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

Question 212

Skull

Answer 212

The skeletal structure of the head minus the lower jaw | - Complex fusion of dermal and endoskeletal elements

Question 213

Shark Skull

Answer 213

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

Question 214

Braincase

Answer 214

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

Question 215

Vertebrate (Bony) Skull

Answer 215

Three main parts - Braincase - Palatal complex - Skull roof

Question 216

Palatal Complex

Answer 216

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

Question 217

Skull Roof

Answer 217

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

Question 218

Tooth-bearing Marginal Series

Answer 218

Series of the skull roof that forms the outer rim Includes - Premaxilla - Maxilla

Question 219

Midline Series

Answer 219

Series of the skull roof with adjacently paired bones on the dorsal side - Nasal - Frontal - Parietal - Postparietal

Question 220

Circumorbital Series

Answer 220

Series of the skull roof that surrounds the orbit - Prefrontal - Postfrontal - Lacrimal - Postorbital - Jugal

Question 221

Temporal Series

Answer 221

Series of the skull roof that lies between the otic notch and the midline series - Intertemporal - Supratemporal - Tabular (?)

Question 222

Cheek Series

Answer 222

Series of the skull roof that lies behind the orbit and below the otic notch - Squamosal - Quadratojugal - Quadrate

Question 223

Pterygoid

Answer 223

``` Largest bone of the palatal complex Paired - Largest of the four - Posterior - Median - Dermal bone ```

Question 224

Ectopterygoid

Answer 224

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

Question 225

Palatine

Answer 225

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

Question 226

Vomer

Answer 226

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

Question 227

Palatoquadrate

Answer 227

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

Question 228

Quadrate

Answer 228

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

Question 229

Epipterygoid

Answer 229

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

Question 230

Parasphenoid

Answer 230

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

Question 231

Supraoccipital

Answer 231

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

Question 232

Basioccipital

Answer 232

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

Question 233

Exoccipital

Answer 233

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

Question 234

Occipital

Answer 234

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

Question 235

Opisthotic

Answer 235

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

Question 236

Prootic

Answer 236

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

Question 237

Basisphenoid

Answer 237

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

Question 238

Sphenethmoid

Answer 238

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

Question 239

Basic changes in tetrapod skulls

Answer 239

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

Question 240

Basal Amniote Skull

Answer 240

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

Question 241

Pelycosaur Skull

Answer 241

First intermediate stage toward a mammalian skull | - Temporal fenestra is developed

Question 242

Non-Mammalian Therapsid Skull

Answer 242

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

Question 243

Anapsid Skull

Answer 243

- Small brain sits in braincase - Dermal skull roof covers brain - No fenestra in skull roof - Jaw muscles attach to inside of dermal skull roof

Question 244

Early Synapsid Skull

Answer 244

- 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

Question 245

Early Therapsid Skull

Answer 245

- Brain larger than in early synapsids - Temporal fenestrae have enlarged - Cranial kinesis is lost

Question 246

Later Therapsid Skull

Answer 246

- 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

Question 247

Mammal Skull

Answer 247

- 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

Question 248

Secondary Palate

Answer 248

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

Question 249

Primary Palate

Answer 249

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

Question 250

Development of the Temporal

Answer 250

Involves complex fusion of dermal and endochondral braincase elements Includes - Squamosal - Petrosal - Ectotympanic - Entotympanic - Malleus - Incus - Stapes

Question 251

Squamosal

Answer 251

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

Question 252

Petrosal

Answer 252

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

Question 253

Ectoympanic

Answer 253

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

Question 254

Entotympanic

Answer 254

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

Question 255

Malleus

Answer 255

Middle ear ossicle that is formed from the primitive articular - Dermal bone - From the old lower jaw

Question 256

Incus

Answer 256

Middle ear ossicle that is formed from the primitive quadrate - Endochondral bone - From the palatal complex

Question 257

Stapes

Answer 257

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

Question 258

Sphenoid Region

Answer 258

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

Question 259

Anterior Sphenoid Region

Answer 259

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

Question 260

Posterior Sphenoid Region

Answer 260

- Basisphenoid (from the braincase) | - Alisphenoid (homologous to the epipterygoids)

Question 261

Presphenoid

Answer 261

Anterior and ventral portion of the sphenoid region | Single

Question 262

Orbitosphenoid

Answer 262

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

Question 263

Basisphenoid

Answer 263

Posterior and ventral portion of the sphenoid region | Single

Question 264

Alisphenoid

Answer 264

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

Question 265

Muscle Categories

Answer 265

Histological - Striated - Smooth Physiological - Voluntary - Involuntary Organizational - Somatic - Visceral

Question 266

Somatic Muscles

Answer 266

Muscles that are derived from the myotomes of somites - Axial and appendicular musculature - Always striated - Mostly voluntary - Innervated by somatic motor fibres

Question 267

Visceral Muscles

Answer 267

Muscles that are derived from the mesenchyme - Branchiomeric and smooth (gut) musculature - Can be smooth or striated - Mostly involuntary - Innervated by visceral motor fibres

Question 268

Origin

Answer 268

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

Question 269

Insertion

Answer 269

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

Question 270

Flexor

Answer 270

A muscle that closes a hinge joint

Question 271

Extensor

Answer 271

A muscle that opens a hinge joint

Question 272

Adductor

Answer 272

A muscle that moves something towards the ventral midline In the jaw, this muscle closes the jaw

Question 273

Abductor

Answer 273

A muscle that moves something away from the ventral midline

Question 274

Depressor

Answer 274

A muscle that opens the jaw

Question 275

Appendicular Musculature

Answer 275

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

Question 276

Axial Musculature

Answer 276

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

Question 277

Epaxial Musculature

Answer 277

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

Question 278

Hypaxial Musculature

Answer 278

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

Question 279

Horizontal Skeletogenous Septum

Answer 279

Septum that divides the epaxial from hypaxial musculature

Question 280

Dorsalis trunci

Answer 280

Epaxial musculature in fish and amphibians

Question 281

Iliocostalis

Answer 281

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

Question 282

Longissimus dorsi

Answer 282

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

Question 283

Transversospinalis

Answer 283

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

Question 284

Subvertebral Series

Answer 284

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

Question 285

Ventral Series

Answer 285

Midventral muscle in the hypaxial musculature in tetrapods | - Rectus abdominis

Question 286

Rectus abdominis

Answer 286

Single muscle of the ventral series in tetrapods | - Stretches from the sternum to the pelvis

Question 287

Lateral Series

Answer 287

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

Question 288

External oblique

Answer 288

Most superficial of the lateral series of musculature

Question 289

Internal oblique

Answer 289

Intermediate layer of the lateral series of musculature

Question 290

Transverse abdominis

Answer 290

Most deep layer of the lateral series of musculature

Question 291

Aponeurosis

Answer 291

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

Question 292

Cranial Muscles

Answer 292

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

Question 293

Axial muscles of the head and neck

Answer 293

Three groups - Extrinsic eye muscles - Epibranchial - Hypobranchial

Question 294

Extrinsic Eye Muscles

Answer 294

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

Question 295

Epibranchial Musculature

Answer 295

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

Question 296

Hypobranchial Musculature

Answer 296

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

Question 297

Ventral oblique

Answer 297

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

Question 298

Medial rectus

Answer 298

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

Question 299

Dorsal rectus

Answer 299

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

Question 300

Ventral rectus

Answer 300

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

Question 301

Dorsal oblique

Answer 301

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

Question 302

Posterior rectus

Answer 302

``` 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 ```

Question 303

Coracoarcuals

Answer 303

Muscles from the hypobranchial musculature that opens the jaws in fishes

Question 304

True Tongue

Answer 304

A muscular structure that is only present in tetrapods | - Formed from hypobranchial musculature

Question 305

Primary Tongue

Answer 305

Non-muscular tongue that is present in fishes

Question 306

Genioglossus

Answer 306

Muscle that extends from the chin to the tongue | - Formed from hypobranchial musculature

Question 307

Geniohyoid

Answer 307

Muscle that extends from the chin to the hyoid apparatus | - Formed from hypobranchial musculature

Question 308

Styloglossus

Answer 308

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

Question 309

Hyoglossus

Answer 309

Muscle that extends from the hyoid to the tongue | - Formed from the hypobranchial musculature

Question 310

Thyrohyoid

Answer 310

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

Question 311

Sternohyoid

Answer 311

Muscle that extends from the sternum to the hyoid | - Formed from the hypobranchial musculature

Question 312

Sternothyroid

Answer 312

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

Question 313

Branchiomeric Musculature

Answer 313

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

Question 314

Superficial constrictor

Answer 314

Continuous, superficial muscle sheet that separates adjacent pharyngeal slits

Question 315

Interbranchial

Answer 315

Continuous, deep muscle sheet that separates adjacent pharyngeal slits

Question 316

Interarcual

Answer 316

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

Question 317

Levator

Answer 317

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

Question 318

Adductor

Answer 318

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

Question 319

Pharyngeal Muscles in Fish

Answer 319

- Individual levators are lost and fuse into single cucullaris - Superficial constrictors and interbranchials lost in bony fishes due to operculum

Question 320

Pharyngeal Muscles in Tetrapods

Answer 320

- Cucullaris replaced by the trapezius | - Almost all other muscles supporting the gill arches disappear with them, though a few remain in the larynx

Question 321

Trapezius

Answer 321

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

Question 322

Sternocleidomastoid

Answer 322

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

Question 323

Muscles of the Hyoid Arch in Fish

Answer 323

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

Question 324

Muscles of the Hyoid Arch in Tetrapods

Answer 324

- 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

Question 325

Sphicter Colli

Answer 325

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

Question 326

Depressor Mandibulae

Answer 326

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

Question 327

Facial Muscles

Answer 327

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

Question 328

Buccinator

Answer 328

Prominent facial muscle in mammals, muscle of the cheek | - Important for chewing as it keeps food in the oral cavity for processing

Question 329

Digastric

Answer 329

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

Question 330

Muscles of the Mandibular Arch in Dogfish

Answer 330

Three groups 1. Adductor mandibulae 2. Dorsal levator/Levator palatoquadrati 3. Ventral muscles inc. intermandibularis

Question 331

Adductor mandibulae

Answer 331

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

Question 332

Dorsal levator

Answer 332

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

Question 333

Intermandibularis

Answer 333

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

Question 334

Mylohyoid

Answer 334

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

Question 335

Mammalian Adductor Musculature

Answer 335

Three main muscles used to close the mouth - Temporalis - Masseter - Pterygoid muscles

Question 336

Temporalis

Answer 336

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

Question 337

Masseter

Answer 337

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

Question 338

Pterygoid Muscles

Answer 338

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

Question 339

Respiratory System

Answer 339

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)

Question 340

Gills

Answer 340

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

Question 341

Pharynx

Answer 341

The anterior part of the gastrocoele in an embryo | - The "throat," where gill pouches occur in the embryo

Question 342

Development of the Pharyngeal Slits

Answer 342

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

Question 343

Pharyngeal Slits in Fishes

Answer 343

Almost always consists of five slits and an optional spiracle

Question 344

Pharyngeal Slits in Cyclostomes

Answer 344

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

Question 345

Pharyngeal Modifications in Cyclostomes

Answer 345

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

Question 346

"Esophagus"

Answer 346

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

Question 347

Respiratory Tube

Answer 347

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

Question 348

Velum

Answer 348

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

Question 349

Pharyngeal Slits in Sharks

Answer 349

Due to interbranchial septa, each slit has a separate opening

Question 350

Pharyngeal Slits in Teleosts

Answer 350

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

Question 351

Respiratory System in Tetrapods

Answer 351

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

Question 352

Glottis

Answer 352

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

Question 353

Lungs

Answer 353

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

Question 354

Swimbladder

Answer 354

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

Question 355

Bronchi

Answer 355

Tubes that branch from the trachea towards the lungs | - Have primary and secondary branching

Question 356

Bronchioles

Answer 356

Tubes that branch from the bronchi towards the lungs

Question 357

Alveoli

Answer 357

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

Question 358

Respiratory System of Birds

Answer 358

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

Question 359

Parabronchi

Answer 359

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

Question 360

The two-cycle respiration system

Answer 360

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

Question 361

Cutaneous Respiration

Answer 361

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

Question 362

Digestive System

Answer 362

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

Question 363

Mechanical Digestion

Answer 363

Physical treatment of food in the digestive system - Action of the visceral muscles that surround the gut - Peristalsis - Reduces food for chemical digestion

Question 364

Peristalsis

Answer 364

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

Question 365

Chemical Digestion

Answer 365

Breakdown of food into molecular components for absorption

Question 366

Absorption

Answer 366

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

Question 367

Divisions of the Gut

Answer 367

- 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

Question 368

Pylorus

Answer 368

Constriction at the beginning of the small intestine - Almost always recognizable in vertebrates - Divides the foregut from the hindgut

Question 369

Foregut

Answer 369

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

Question 370

Esophgus

Answer 370

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

Question 371

Stomach

Answer 371

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

Question 372

Hindgut

Answer 372

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

Question 373

Intestine

Answer 373

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

Question 374

Small Intestine

Answer 374

Anterior portion of the intestinal tract Three sections - Duodenum - Jejunum - Ileum

Question 375

Duodenum

Answer 375

First loop of the small intestine

Question 376

Ileocecal Valve

Answer 376

Represents the separation between the small and large intestine

Question 377

Large Intestine

Answer 377

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

Question 378

Cloaca

Answer 378

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

Question 379

Rectum

Answer 379

Ending of the digestive system alone

Question 380

Cecum

Answer 380

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

Question 381

Pyloric Cecum

Answer 381

Ceca occurring between the stomach and intestine, as in fish | - Three occur in the perch

Question 382

Crop

Answer 382

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

Question 383

Salivary Glands

Answer 383

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

Question 384

Proventriculus

Answer 384

Proximal, glandular part of the stomach in birds | - Secretes gastric juices to aid in digestion

Question 385

Gizzard

Answer 385

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

Question 386

Ruminant Stomach

Answer 386

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

Question 387

Ruminant Digestion

Answer 387

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

Question 388

Increasing Surface Area of the Intestine

Answer 388

Four Methods 1. Lengthen 2. Spiral Valve 3. Cecum 4. Roughen internal surface

Question 389

Lengthening of the intestine

Answer 389

Results in a longer tube and therefore more surface area | - Mainly seen in teleosts and tetrapods

Question 390

Spiral valve in the intestine

Answer 390

Results in lengthening and slowing of food passage - Typically seen in primitive jawed fish - Typhosole of lamprey may be related

Question 391

Roughening of intestinal surface

Answer 391

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

Question 392

Villi

Answer 392

Finger-like projections of the internal lining of the intestine

Question 393

Microvilli

Answer 393

Projections found on the individual cells within the intestine

Question 394

Mouth

Answer 394

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

Question 395

Stromodeum

Answer 395

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

Question 396

Oral Cavity

Answer 396

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

Question 397

Rathke's Pouch

Answer 397

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

Question 398

Nasal Pit

Answer 398

A.K.A. Nasal placode | Small pocketing of the stomodeum in the embryo that forms the olfactory epithelium

Question 399

Structures in the Oral Cavity

Answer 399

- Tongue in terrestrial vertebrates - Vomeronasal Organ - Various Oral Glands

Question 400

Uses of the Tongue

Answer 400

- 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

Question 401

Vomeronasal Organ

Answer 401

A.K.A. Jacobson's Organ | Organ in the roof of the oral cavity used in the chemical detection of pheromones and prey

Question 402

Oral Glands

Answer 402

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

Question 403

Pharyngeal Glands

Answer 403

Glands that develop in the pharynx - Thyroid - Thymus

Question 404

Thyroid Gland

Answer 404

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

Question 405

Thymus Gland

Answer 405

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

Question 406

Denticles

Answer 406

Keratinized, tooth-like cones present in cyclostomes - Associated with the mouth and rasping tongue - Used to cling to prey and rasp off flesh

Question 407

True teeth

Answer 407

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

Question 408

Homodont

Answer 408

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

Question 409

Heterodont

Answer 409

Teeth that are complex and differentiated | - Mammalian teeth

Question 410

Acrodont

Answer 410

Teeth that are loosely attached to the jaw by ligaments - Sit on top of the jaw - Seen in teleosts, Sphenodon

Question 411

Pleurodont

Answer 411

Teeth that are braced on one side, so half in a socket | - Condition of many lizards

Question 412

Thecodont

Answer 412

Teeth that are fully placed into a socket in the jaw | - Mammals, archosaurs

Question 413

Crown

Answer 413

Portion of a tooth that is exposed above the gumline

Question 414

Root

Answer 414

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

Question 415

Alveolus

Answer 415

Socket within which a tooth sits in the jaw

Question 416

Pulp Cavity

Answer 416

Cavity within a tooth in which blood vessels and nerves reside

Question 417

Enamel

Answer 417

Substance that typically covers the crown of a tooth - Hardest substance in the body - Is not always present

Question 418

Dentine

Answer 418

Substance that forms the bulk of a tooth | - Main supporting structure

Question 419

Cementum

Answer 419

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

Question 420

Polyphyodonty

Answer 420

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

Question 421

Diphyodonty

Answer 421

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

Question 422

Monophyodonty

Answer 422

Condition where teeth are never replaced | - Typical of toothed whales and sloths

Question 423

Incisors

Answer 423

Mammalian teeth found in the premaxilla

Question 424

Canines

Answer 424

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

Question 425

Premolars

Answer 425

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

Question 426

Molars

Answer 426

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

Question 427

Ancestral Tooth Formula of Placental Mammals

Answer 427

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

Question 428

Coelom

Answer 428

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

Question 429

Somatic Layer of Hypomere

Answer 429

Forms the parietal, or somatic, peritoneum | - Lines the outer tube: somatopleure

Question 430

Visceral Layer of Hypomere

Answer 430

Forms the visceral, or sphlanchnic, peritoneum | - Covers the inner tube of the body: splanchnopleure

Question 431

Somatopleure

Answer 431

Formed from the somatic mesoderm and ectoderm

Question 432

Splanchnopleure

Answer 432

Formed from the splanchnic mesodern and endoderm

Question 433

Dorsal mesentery

Answer 433

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

Question 434

Ventral mesentery

Answer 434

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

Question 435

Pericardial Cavity

Answer 435

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

Question 436

Transverse Septum

Answer 436

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

Question 437

Pleuropericardial Membrane

Answer 437

Dorsal extension of the transverse septum in tetrapods | - Due to development of the neck pushing the pericardial cavity back

Question 438

Pleural Cavity

Answer 438

Cavity within which the lungs reside | - In mammals and many reptiles

Question 439

Peritoneal Cavity

Answer 439

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

Question 440

Pleuroperitoneal Cavity

Answer 440

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

Question 441

Pleuroperitoneal Membrane

Answer 441

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

Question 442

Diaphragm

Answer 442

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

Question 443

Central Tendon

Answer 443

Feature of mammals | - Formed from the transverse septum

Question 444

Mesenteries

Answer 444

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

Question 445

Liver

Answer 445

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

Question 446

Lesser Omentum

Answer 446

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

Question 447

Falciform Ligament

Answer 447

Stretches between the liver and the ventral body wall | - Remnant of the ventral mesentery

Question 448

The Mesentery

Answer 448

The portion of the dorsal mesentery that supports the small intestine

Question 449

Mesocolon

Answer 449

The portion of the dorsal mesentery that supports the large intestine

Question 450

Mesorectum

Answer 450

The portion of the dorsal mesentery that supports the rectum

Question 451

Greater Omentum

Answer 451

A.K.A. Mesogaster | The portion of the dorsal mesentery that supports the stomach

Question 452

Omental Bursa

Answer 452

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

Question 453

Lesser Peritoneal Cavity

Answer 453

Space contained within the omental bursa

Question 454

Gastroepiploic Foramen

Answer 454

The entrance into the lesser peritoneal cavity

Question 455

Hepatic Duct

Answer 455

Carry bile from the liver to the common bile duct

Question 456

Cystict Duct

Answer 456

Carries bile from the gallbladder to the common bile duct

Question 457

Common Bile Duct

Answer 457

Carries bile from the hepatic and cystic ducts to the gut

Question 458

Gallbladder

Answer 458

Small organ off of the liver that stores a reserve of bile | - Forms as an outgrowth of the hepatic duct

Question 459

Functions of the Liver

Answer 459

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

Question 460

Bile

Answer 460

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

Question 461

Pancreas

Answer 461

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

Question 462

Exocrine Gland

Answer 462

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.

Question 463

Endocrine Gland

Answer 463

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

Question 464

Exocrine Functions of the Pancreas

Answer 464

Produces "pancreatic juice" - Mixture of various alkaline enzymes and proenzymes - Neutralizes acidic materials coming from the stomach

Question 465

Endocrine Functions of the Pancreas

Answer 465

Found in pancreatic islets scattered between the exocrine portion - Produce insulin and glucagon - Both important in controlling glucose blood levels

Question 466

Spleen

Answer 466

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

Question 467

Hemopoetic

Answer 467

Something that forms lood cells

Question 468

Cardiovascular System

Answer 468

Has four basic components 1. Heart 2. Arteries 3. Veins 4. Capillaries

Question 469

Heart

Answer 469

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

Question 470

Arteries

Answer 470

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

Question 471

Veins

Answer 471

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

Question 472

Capillaries

Answer 472

System of tiny vessels that connect arteries and veins | - The area for blood exchange - arteries and veins are for transport

Question 473

Portal Veins

Answer 473

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

Question 474

Functions of the Cardiovascular System

Answer 474

- 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

Question 475

Blood Circulation in Gilled Animals

Answer 475

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)

Question 476

Blood Circulation in Teatrpods

Answer 476

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)

Question 477

Subintestinal Veins

Answer 477

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

Question 478

Hepatic Vein

Answer 478

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

Question 479

Hepatic Portal Vein

Answer 479

Portal vein that stretches from the gut to the liver

Question 480

Dorsal Veins

Answer 480

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

Question 481

Common Cardinal Vein

Answer 481

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

Question 482

Anterior Cardinal Veins

Answer 482

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

Question 483

Posterior Cardinal Veins

Answer 483

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

Question 484

Caudal Vein

Answer 484

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

Question 485

Renal Portal Vein

Answer 485

Veins that extend between the caudal vein and the kidneys | - Found in gnathostomes but not agnathans

Question 486

Lateral Head Vein

Answer 486

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

Question 487

Cranial Veins in Mammals

Answer 487

- 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

Question 488

Anterior Vena Cava

Answer 488

Single remaining anterior cardinal vein in higher vertebrates

Question 489

Posterior Vena Cava

Answer 489

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

Question 490

Azygos Vein

Answer 490

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

Question 491

Abdominal Veins

Answer 491

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

Question 492

Iliac Vein

Answer 492

- 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

Question 493

Pulmonary Vein

Answer 493

- 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

Question 494

Sinus Venosus

Answer 494

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

Question 495

Conus Arteriosus

Answer 495

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

Question 496

Lungfish Heart

Answer 496

- 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

Question 497

Amphibian Heart

Answer 497

- 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

Question 498

Reptile Heart

Answer 498

- 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

Question 499

Crocodile Heart

Answer 499

- 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

Question 500

Foramen of Panniza

Answer 500

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

Question 501

Mammal/Bird Heart

Answer 501

- 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

Question 502

Lungfish & Amphibian Conus Arteriosus

Answer 502

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

Question 503

Amniote Conus Arteriosus

Answer 503

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

Question 504

Lymphatics

Answer 504

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

Question 505

Lymph Hearts

Answer 505

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

Question 506

Lymphocytes

Answer 506

White blood cells | - Produced in lymph nodes in mammals

Question 507

Chyle

Answer 507

Fatty lymph

Question 508

Atrium

Answer 508

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

Question 509

Ventricle

Answer 509

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

Question 510

Aortic Arches

Answer 510

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

Question 511

Afferent Branchial Arteries

Answer 511

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

Question 512

Efferent Branchial Arteries

Answer 512

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

Question 513

Ventral Aorta

Answer 513

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

Question 514

Dorsal Aorta

Answer 514

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

Question 515

Aortic Arch System of Sharks

Answer 515

- 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

Question 516

External Carotid Artery

Answer 516

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

Question 517

Mandibular Artery

Answer 517

Artery between the mouth and spiracle in jawed fishes | - Modified from aortic arch I

Question 518

Hyoid Artery

Answer 518

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

Question 519

Afferent Spiracular Artery

Answer 519

Artery that supplies the spiracle in primitive fish | - Branch of the efferent branchial artery of aortic arch II, so blood is oxygenated

Question 520

Efferent Spiracular Artery

Answer 520

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

Question 521

Aortic Arch System of Most Bony Fishes inc. Lungfish

Answer 521

- Aortic arch II is lost | - Only arches III-VI are present

Question 522

Pulmonary Artery

Answer 522

Artery leaving the lung - Developed in fish with lungs as a branch of aortic arch VI - Blood already oxygenated

Question 523

Aortic Arch System of Tetrapods

Answer 523

- 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

Question 524

Aortic Arch System of Adult Amphibians

Answer 524

- 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

Question 525

Ductus Arteriosus

Answer 525

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

Question 526

Carotid Duct

Answer 526

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

Question 527

Internal Carotid Artery

Answer 527

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

Question 528

Common Carotid Artery

Answer 528

Forms from the ventral aorta that leads to aortic arch III

Question 529

External Carotid Artery

Answer 529

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

Question 530

Systemic Arches

Answer 530

Main supply of blood to the body from the heart | - Formed from aortic arch IV

Question 531

Trunks of the Heart in Reptiles

Answer 531

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

Question 532

Trunks of the Heart in Birds

Answer 532

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

Question 533

Trunks of the Heart in Mammals

Answer 533

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

Question 534

Orbital Artery

Answer 534

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

Question 535

Urogenital System

Answer 535

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

Question 536

Kidney

Answer 536

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

Question 537

Holonephros

Answer 537

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

Question 538

Nephric Units

Answer 538

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

Question 539

Longitudinal Duct

Answer 539

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

Question 540

Archinephric Duct

Answer 540

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

Question 541

Pronephros

Answer 541

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

Question 542

Opisthonephros

Answer 542

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

Question 543

Mesonephros

Answer 543

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

Question 544

Metanephros

Answer 544

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

Question 545

Ureter

Answer 545

Duct that drains the tubules of the metanephros | - Develops from back to front and before the metanephros tubules; may even induce their formation

Question 546

Anamniote Kidney

Answer 546

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

Question 547

Gonadial Ducts

Answer 547

Ducts responsible for the transport of gametes | - Primitively, none actually existed and gametes were shed directly into the coelom

Question 548

Gonadial Ducts in Cyclostomes

Answer 548

None! | - Sperm & ova shed directly into the coelom and find way to cloaca through abdominal pores

Question 549

Gonadial Ducts in Gnathostomes

Answer 549

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

Question 550

Ovarian Duct

Answer 550

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

Question 551

Testis

Answer 551

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

Question 552

Vas Deferens

Answer 552

Name for the archinephric duct when used solely for sperm passage

Question 553

Cyclostome Urogenital Ducts

Answer 553

- Archinephric duct used for urine by kidney | - No ducts developed for use by testes or ovaries

Question 554

Teleost Urogenital Ducts

Answer 554

- Archinepric duct used by kidney for urine - Testes develop their own duct for sperm - Ovarian duct developed for ova

Question 555

Anamniote Urogenital Ducts

Answer 555

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

Question 556

Amniote Urogenital Ducts

Answer 556

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

Question 557

Nervous System

Answer 557

Sensory system that develops very early on in vertebrate embryos Two kinds - Central Nervous System - Peripheral Nervous System

Question 558

Central Nervous System

Answer 558

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

Question 559

Peripheral Nervous System

Answer 559

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

Question 560

Peripheral Nerves

Answer 560

Nerves of the peripheral nervous system | - Made of fibres, i.e. axons of neurons

Question 561

Cell Body

Answer 561

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

Question 562

Ganglia

Answer 562

Swellings that contain clusters of cell bodies | - Part of the peripheral nervous system

Question 563

Axon

Answer 563

The long extesio of a neuron

Question 564

Reflex Arc

Answer 564

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

Question 565

Sensory Neuron

Answer 565

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

Question 566

Motor Neuron

Answer 566

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

Question 567

Inter-neuron

Answer 567

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

Question 568

Somatic Sensory Nerves

Answer 568

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

Question 569

Somatic Motor Nerves

Answer 569

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

Question 570

Visceral Sensory Nerves

Answer 570

Nerves that carry signals from the gut to the brain

Question 571

Visceral Motor Nerves

Answer 571

Nerves that carry signals from the brain to the gut muscles, blood vessels and glands Two subdivisions - Autonomic - Special Branchial

Question 572

Autonomic Nerves

Answer 572

Involuntary, visceral motor nerves associated with the gut Two types - Parasympathetic - Sympathetic

Question 573

Special Branchial Nerves

Answer 573

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

Question 574

Spinal Nerves

Answer 574

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

Question 575

Dorsal Root (Higher Vertebrates)

Answer 575

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

Question 576

Ventral Root (Higher Vertebrates)

Answer 576

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

Question 577

Spinal Nerve Roots in Lower Vertebrates

Answer 577

- 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

Question 578

Spinal Nerve Roots in Amphioxus

Answer 578

- 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

Question 579

Tripartite Brain

Answer 579

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

Question 580

Prosencephalon

Answer 580

Anterior part of the tripartite brain - Defined posteriorly by a downward flexure - Initially associated with nasal function - Gives rise to the telencephalon and diencephalon

Question 581

Mesencephalon

Answer 581

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

Question 582

Rhombencephalon

Answer 582

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

Question 583

Brain Stem

Answer 583

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

Question 584

Telencephalon

Answer 584

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

Question 585

Diecephalon

Answer 585

Second part of the five-part brain - Consists of the thalamus, epithalamus and hypothalamus - Contains the third ventricle - Formed from the prosencephalon

Question 586

Metencephalon

Answer 586

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

Question 587

Myelencephalon

Answer 587

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

Question 588

Ventricles of the Brain

Answer 588

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

Question 589

Lateral Ventricles

Answer 589

Paired ventricles found in the cerebral hemispheres of the telencephalon

Question 590

Third ventricle

Answer 590

Ventricle found in the diencephalon

Question 591

Optic ventricle

Answer 591

Ventricle found in the mesencephalon | - Lost in mammals and birds

Question 592

Cerebellar Ventricle

Answer 592

Ventricle found in the metencephalon | - Becomes an extension of the fourth ventricle in higher vertebrates

Question 593

Fourth Ventricle

Answer 593

Ventricle found in the myelencephalon

Question 594

Cranial Nerves

Answer 594

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 ```

Question 595

Special Visceral Sensory Nerves

Answer 595

Nerves of the taste organs

Question 596

Special Somatic Sensory Nerves

Answer 596

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

Question 597

Basic Types of Cranial Nerves

Answer 597

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

Question 598

Terminalis Nerve

Answer 598

Cranial Nerve 0 | - Dorsal Root, somatic sensory nerve

Question 599

Olfactory Nerve

Answer 599

Cranial Nerve I | - Special somatic sensory nerve

Question 600

Optic Nerve

Answer 600

Cranial Nerve II | - Special somatic sensory nerve

Question 601

Oculomotor Nerve

Answer 601

Cranial Nerve III - Ventral Root, somatic motor nerve - Develops in first preotic somite - Splits into ventral oblique; dorsal, ventral and medial rectus

Question 602

Trochlear Nerve

Answer 602

Cranial Nerve IV - Ventral Root, somatic motor nerve - Develops in second preotic somite - Enters the dorsal oblique

Question 603

Profundus Nerve

Answer 603

Cranial Nerve V(1) | - Dorsal Root, somatic sensory and visceral motor nerves

Question 604

Trigeminal Nerve proper

Answer 604

Cranial Nerve V(2,3) - Nerve of the mandibular arch - Dorsal Root, somatic sensory and special visceral motor nerves

Question 605

Abducens Nerve

Answer 605

Cranial Nerve VI - Ventral Root, somatic motor nerve - Develops in third preotic somite - Enters the lateral rectus

Question 606

Facial Nerve

Answer 606

Cranial Nerve VII - Nerve of the hyoid arch - Dorsal Root: all types of nerves except somatic motor nerves

Question 607

Acoustic Nerve

Answer 607

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

Question 608

Glossopharyngeal Nerve

Answer 608

Cranial Nerve IX - Nerve of the first branchial arch - Dorsal Root: all types of nerves except somatic motor nerves

Question 609

Vagus Nerve

Answer 609

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

Question 610

Hypoglossal Nerve

Answer 610

``` 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 ```

Question 611

Lateral Line Nerves

Answer 611

Usually two sets, both anterior and posterior - Special somatic sensory nerves - Usually enter the braincase alongside some branchial nerves, but are different

Question 612

Major Modifications Occurring in the Head

Answer 612

- Branchial region introduced and enlarged - Special sensory organs arose - Mouth enlarged - Brain enlarged

Question 613

Ventral Root Nerves

Answer 613

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