ZOO 2090 lecture post midterm Flashcards
1
Q
What are the main groups of modern amphibians?
Hint: 3
A
- Frogs and toads
- Salamanders (and newts)
- Caecilians
2
Q
What are the types of glands found in amphibian skin and what are their function?
A
- Mucous glands –> secrete mucus to help with cutaneous respiration
- Granular glands–> secrete poisonous alkaloid compounds for defense
3
Q
What are some characteristics of the amphibian skin? Explain their significance briefly.
A
- Skin is thin.
- allows for easier gas exchange (cutaneous respiration) - More terrestrial forms have more keratin (fibrous protein).
- keep it from drying out
- good for defense (less tearing of skin) - Some caecilians and toads have bone elements in the dermis.
- for protection
4
Q
Often, amphibians go through metamorphosis during development (eggs –> water –> some mixed –> terrestrial).
However, some species have their entire developmental process in the egg, and come out as adults. Why might this be adaptive?
A
- Breaks link with adult forcing them to always be around water to reproduce
- Eggs can be up in trees for protection, with no ponds nearby
*This is a derived state found in the tropics
5
Q
What kind of teeth do amphibians have? How are they divided?
A
- Pedicellate teeth
- Crown (dentified tip) of calcified dentin aries from the pedicel (base), connected by the uncalcified suture
6
Q
Amphibian teeth are homologous to mammal teeth in the way they are derived. True or False?
A
False.
Amphibian teeth are not homologous to mammalian teeth (enamel, dentin, etc), they arise differently.
7
Q
What are some characteristics of the species in the order Anura?
(limbs, tail, tympanum?, fertilization)
A
- Paired limbs
- Absence of tail (adults)
- Jumpers
- Tympanum usually present to transmit sound to inner ear
- External fertilization, except in Ascaphus–extension of male cloaca
8
Q
What is are some characteristics of the Anura skull?
A
- Flattened, open, with big jaws
- Palate is highly reduced
- Allows eyeballs to drop into oral cavity
- Significance: helps force food down throat - Hyomandibula becomes the stapes
- Significance: Sound transmission, works with tympanum in inner ear
9
Q
What are some key differences in the axial skeleton of anuras that makes it specialized?
A
- Vertebrae
- fewer
- different kinds
- sacral & pelvic girdle have close affinity
- Urostyle –> fused vertebrae - Atlas –> allows for winder range of motion in head
10
Q
How many vertebrae does the axial skeleton of an anura have?
A
9 or less
11
Q
What is a urostyle and where is it found?
A
Urostyle –> post sacral vertebrae fused into a rod-shape
-found between the two elongated illium bones of the pelvic girdle
12
Q
What are some main features of the anura appendicular skeleton?
A
- Pectoral girdle and radius/ulna are used to absorb the shock of landing
- Tibia/fibula and ankle bones are also fused for sturdiness
- Increase in length of hind limbs –> characteristic of jumpers
13
Q
In frogs, both the tibia/fibula and the radius/ulna are fused. True or False?
A
True.
Tibia/fibula –> sturdiness
Radius/Ulna –> shock absorbance
14
Q
What order are salamanders part of?
A
Order Caudata
15
Q
What are some characteristics of salamanders?
limbs, type of feeding, tympanum?, fertilization
A
- Paired limbs and a long tail
- Suction feeding in water and projectile tongue on land
- No tympanum present
- Fertilization can be external or internal by means of spermatophore transfer
16
Q
How many pre-sacral vertebrae do salamanders have?
A
10-60 (have a long back)
17
Q
What are some characteristics of the salamander skeleton?
A
- Flattened opened skull with large orbits
- Poor ossification
- Reduction and loss of bones is common
18
Q
What kind of locomotion do salamanders have?
A
Dual locomotion.
19
Q
What order do caecilians belong to?
A
Gymnophiona.
20
Q
Why do caecillians have a solid and compact skull?
Hint: they have no limbs or girdles
A
They have this kind of skull so that they are able to burrow.
21
Q
How many trunk vertebrae do caecilians have?
A
60-285, but tail is short/ absent.
22
Q
What are some characteristics about caecilians?
Habitat, Fertilization, hatchlings
A
- Restricted to tropical habitats
- Internal fertilization
- Hatchlings are aquatic or terrestrial
23
Q
How do caecilians compensate for reduced eyes?
A
They have paired tentacles in the front of their head, which help with chemosensation in dark tunnels.
24
Q
What is a “Frogamander” and how does it contribute to our evolutionary knowledge about amphibians?
A
The “Frogamander” is a fossil found of a species that has features excursively from frogs and features exclusively from salamanders, but not both.
It links salamanders and frogs to one phylogenetic line (have affinity with temnospondyii).
25
What are the hypotheses of amphibian origin? Give a brief description of each.
1. Polyphyletic hypothesis
- Eocaecilia with Lepidospondyii
- Anura and Caudata with Temnospondyii
2. Monophyletic hypothesis
- Affinity of Eocaecilia with Anura and Caudata (Temnospondyii origins)
26
What is the main reason there are conflicting hypotheses about amphibian evolution?
Relationship determination is often dependent on the characters used in comparison.
(different character = different phylogeny determination)
+Amphibians show complex patterns of morphology during development.
27
What is Heterochrony and Paedomorphosis, and how does it relate to evolutionary determinations of amphibians?
- Heterochrony--> changes in the timing and rate of developmental events between ancestors and descendants
ex. Mountain form retains larval morphology at reproduction -no metamorphosis into terrestrial form
- Paedomorphosis--> larval characteristics of ancestors appear in adults of descendants
28
Why can paedomorphosis mislead us? (amphibian evolution)
1. Two unrelated groups with the same aquatic lifestyle could show loss of bones and reduction in ossification to help with buoyancy
- Might conclude they are closely related
2. Choice of characters to determine origin and relationships of modern amphibians is hotly debated
3. Molecular data suggest modern amphibians arose from common ancestor (not polyphyletic)
29
What are some characteristics of early amniotes?
| (time period, skeleton, jaw/teeth)?
- Evolved in the early/mid-Carboniferous (360-330 mya)
- Were often small (~20 cm long) and had a slight but highly ossified skeleton.--“lizard like”
- The jaws, teeth and neck are modified for improved predation
30
What is the evolution of amniotes? (Cambrian, Devonian, Carboniferous)?
```
Cambrian:
-first vertebrate, first chordates
Devonian:
-age of fishes (diversity)
-early tetrapods
Carboniferous:
-first amniotes
```
31
What are synapsids and sauropsids?
Synapsids: mammals
Sauropsids: reptiles and birds
32
What are the types of diapsids?
Lepidosaurs --> lizards and snakes
| Archosaurs --> dinosaurs, birds, crocs
33
What are some characteristics of the amniote cleodic egg?
- a semi-permeable shell which allows gases to pass (O2, CO2), but keeps fluids inside
- Extra-embryonic membranes
34
What are the functions of the extra-embryonic membranes in amniote eggs?
1. Protection and gas transfer:
- Amnion surrounds the embryo with water
- Chorion surrounds the embryo and yolk sac
2. Respiration and waste storage:
- Allantois fills with waste as yolk proteins are used
35
What is the significance of the cleidoic egg?
| 3/4
1. Allowed full development of the organism on land and loss of the larval stage
2. Living on land led to more efficient respiration (gas exchange)
3. Allowed embryo to become larger before hatching compared to amphibians
4. More energy invested in each egg
36
What are some other derived characters of amniotes? Give a brief description of each.
(Hint: skin permeability, lungs, body support)
1. Low skin permeability
- greater variation in skin (keratin)
- presence of lipids
2. Ventilation of lungs aided by ribs (costal)
- allowed for a long neck to draw air through a long tube
- space for elaboration of the nerves that supply the forelimb
3. Body support
- increased apparent weight (gravity) on land required stronger/stiffer skeletons
37
What were the benefits of the loss of lumbar ribs in many amniotes?
1. No ribs in the way of hindlimb forward movement
2. Allowed vertical plane flexion of the column
- easier limb oscillation
- rapid locomotion
38
What are the new joints in the atlas and axis vertebrae? What is their functional significance?
1. Skull-atlas joint
- vertical nodding and horizontal tilting of the head
2. Atlanto-axial joint
- twisting movement
*This configuration sets up better movement
39
How do the reduced centra and processes benefit amniotes?
They are able to maintain bony strength of neck while allowing cranial mobility.
40
Amniotes have to deal with gravity when it comes to the support of their body (which is suspended between its legs). How do they do that?
Amniotes use vertebral column as a "bridge" between support posts (increases support strength):
- Trunk verterbrae--> held in an archer’s bow-like arch by abdominal muscles and sternum
- Cervical vertebrae --> held in a violin bow-like reversed arch by neck ligaments
41
How are early amniotes (dinosaurs) able to stand upright? Give a brief description of each obstacle they faced/ character their bodies needed.
(2)
1. Need to balance heavy body parts against each other
- Hip acts like a fulcrum
2. Requires a firm vertebral column
- Vertebrae likely tied together by strong ligaments between neural spines
42
How did amniotes deal with mechanical forces acting on the vertebral column due to axial muscles?
(2)
1. Direction and height of vertebral neural spines are modified
- Spines are parallel with forces imposed by axial muscles
- Spine height is proportional to leverage needed to stabilize column
2. Ligaments join shoulder neural spines to skull and neck vertebrate and help support a heavy head e.g., bison
43
How did limb posture change in mammals and dinosaurs? How did these changes benefit them?
(2)
1. Limbs are situated under the body
- Increased efficiency of limb swing during rapid locomotion
2. Digit and limb position also allowed inward rotation
- Forward thrust was better aligned with the direction of movement
44
Amniotes vary in the number of fenestrae they have behind the orbit. What could have caused this?
- Early splits in amniote evolution (mid-Carboniferous)
| - Evolution to reduce skull weight and provide attachment edges for jaw muscles
45
What are the different categories of temporal fenestrae?
| 3
```
1. Anapsid--> no temporal fenestrae
(earliest amniotes and turtles)
2. Synapsid--> one lower temporal fenestra
(extinct synapsids and mammals)
3. Diapsid--> two temporal fenestrae
(reptiles, birds, dinsosaurs)
```
46
What are the dorsal carapace and central plastron of turtles made up of?
Dorsal carapace and ventral plastron made up of fused bony elements covered by keratin scutes, attached on the sides.
47
What are the two major components of the turtle body plan?
1. Shell: vertebrae, ribs, osteoderms, scutes (keratin)
| 2. Position of scapula: inside of rib cage
48
What are the two hypotheses for turtle body plan evolution?
1. Gradual transformation
- evidence from fossil records
2. Rapid evolution via changes in developmental regulation
-positioning of scapula & ribs
start to see intermediate forms of body plan
49
What are the 3 main types of Lepidosaurs?
- Tuatara
- Lizards
- Snakes
50
Snakes evolved before lizards. True or False?
False.
51
What are some skull adaptation in lizards and snakes?
| 4
1. Loss of temporal bar(s) around fenestrae
- Lizards: Lower absent
- Snakes: Upper and lower absent
2. Opening up of skull
- Allows bigger food to be swallowed
3. Transcranial joint(s) across the top of the skull
- Snakes: Front of orbit (single)
- Lizards: Rear of orbit and back of skull (double)
4. Ability of quadrate bone to rotate about dorsal connection with braincase
52
Describe the two steps of cranial kinesis in lizards. What is the function significance?
1. Opening –snout tips up
2. Closing –snout tips down
•Equal perpendicular force of both jaws on food item
-keep food/ prey in mouth
53
Describe cranial kinesis in snakes.
- Lower jaw is loosely hinged
- Two sides of mandible can come apart (only connected by muscle and skin)
- Skull and upper jaws are moveable
- Moveable quadrate bone links jaw and skull
54
What are the 4 types of crawling locomotion? Give a brief description of each.
1. Lateral undulation
- Moving waves push sideways against contact points
- Generates a reaction force with a forward component (lateral components cancel out)
2. Concertina movement
- Energy costly
- used in narrow spaces (tunnels)
- involves stationary coils wedging the animal into place while free body parts move forward
3. Sidewinding (colubroidsnakes)
- used over sandy soil
- body contacts 2 or 3 straight tracks at a time with different segments in succession as they are released from previous track
- only segments between tracks are moving
3. Rectilinear movement
- slowest, but discreet
- used by many snakes
- Requires specialized muscles progressively lifting and bringing forward ventral scutesto peg them to the ground
- Body not in contact with ground is moved forward within very distensible skin
55
What are some physical characteristics of crocodilians?
- nostrils, eyes and ears on the head
- Eyelid is transparent
- Bony flaps in throat
56
Crocodilians are able to regulate body temperature by lying with its mouth open. True or False?
True.
57
How many chambers does the heart of a crocodilian have?
4.
58
What is the most important skill about Pterosaurs? How did they gain this ability?
They were the first vertebrate group to evolve powered flight.
- Used membranous wings supported by elongated forelimb
- Early forms had long tails and elongated forelimb
- Later forms lost tail and teeth; had projection at back of head
59
What are the two major groups of dinosaurs? How are they distinguished?
Two major groups: Saurischia and Ornithischia
Distinguished by the structure of the pelvic girdle
- Saurischia: girdle bones radiate outward from the centre
- Ornithischia: ischium and part of pubis are parallel and project backwards
60
What kind of diet did Saurischians have? Give some examples from the 3 groups.
Herbivourous and carnivorous
Examples: 5.Apatosaurus, Diplodocus)
6. bipedal (e.g., Tyrannosaurus, Velociraptor)
7. Archaeopteryx, birds likely evolved from this group
61
What was the diet of Ornithiscians? Give some examples from the 4 groups.
All herbivorous
Examples:
1. Ankylosaurs and stegosaurs
2. Duck-bills
3. Head-buters
4. Triceratops
62
What were some skeletal adaptations that giant dinosaurs had to have?
(3)
1. Shortened pillar-like limbs (weight support)
2. Reduction/shortening of wrist/fingers and ankle/toes
3. Elongated necks -more, longer, but lighter cervical vertebrae
63
Who was the biggest Archosaur competitor of the early dinosaurs?
Archosaur competitor of early dinosaurs -Crurotarsans
| -Died out by chance, despite their larger range of phenotypes and similar evolutionary rates to dinosaurs
64
Why did dinosaurs prevail during their time?
Dinosaurs prevailed because of one or several key adaptations which allowed them to take advantage of empty niches.
65
When did the K-T mass extinction occur?
The end of the Cretaceous period.
66
Around when did Aves first originate?
```
the Jurassic (~170 mya)
(They likely evolved from dinosaurs)
```
67
What is the advantage of wings/flying?
Flyers can gain access to flying prey, escape from non-flying predators, and have unrivaled migratory abilities.
68
Do all aves use wings to fly?
No. Locomotion is varied -wings exclusively to swim (e.g., penguins) or not used (e.g., ostriches)
69
What are the hypotheses about the origin of flight?
Older ideas:
1. Arboreal hypothesis: gliding from tree to tree
2. Cursorial hypothesis: running start and lifted off the ground for insect foraging
New ideas:
1. Use wings to scale inclined objects and trees
70
What are the skeletal adaptations in birds?
| Skull, Neck, Backbone, Pelvic girdle
Skull:
-Reduced number of bones and thinner bones; no teeth (beak). Light weight
Neck:
- Exceptional flexibility -compensate for the loss of fore limbs.
- Heterocoelous cervical vertebrae
Backbone:
-Very rigid to minimize the number of muscles needed to maintain the streamlined body during flight, thereby reducing the energy consumption
Pelvic girdle fused with synsacrum:
-Bipedal; no symphysis (pelvic bones not fused) so large outlet for massive eggs
71
What are the different types of vertebral centra in Archosaurs? Where are they found?
```
1. Acoelous
(most mammals)
2. Amphicoelous
(fishes, some salamanders, some lizards)
3. Procoelous
(anurans, most living reptiles)
4. Opisthocoelous
(most living salamanders)
5. Heterocoelous
(birds)
```
72
What is the synsacrum of birds make up of?
- Thoracic vertebrae
- Lumbar vertebrae
- Sacral vertebrae
- Caudal vertebra
73
What is significant about the sternum in birds?
It is ossified and well pronounced keel (carina) to provide attachment for flight muscles.
74
What is the main similarity of the integument of sauropsids? (reptiles and birds)
They both have epidermal derivatives.
75
Do reptiles have glands in their integument? If yes, what are they used for?
Relatively few glands –dry integument
| -Glands produce poisons, pheromones as signals for sex, identity, navigation
76
Do birds have glands in their integument? If yes, what are they used for?
Single large gland -uropygial gland produces oily secretion for transfer to feathers
-Waterproofing, well developed in aquatic birds
77
What are a few characteristics of reptile epidermal derivatives?
Have well developed epidermal keratinized (horny) scales (scute)
- continuous folds of epidermis
- shed regularly in lizards and snakes
- protection from desiccation
- Used for locomotion (snakes)
78
What are a few characteristics of bird epidermal derivatives?
- Scales in places without feathers
- Claws at the ends of digits
- Beaks often include tooth like protuberances (not true dermal teeth)
- Feathers for thermoregulation, locomotion and attract mates
79
Mammals evolved many years after the first reptiles. True or False?
False. Mammals originally evolved before reptiles, but weren't too diverse/ abundant until afterwards.
80
What kind of synapsids are Pelycosaurs?
Pelycosaurs are basal synapsids. (basal amniotes)
81
What reptiles arose in Carboniferous before lineage and eventually led to modern reptiles?
Pelycosaurs.
82
How many temporal openings do Pelycosaurs have? How does this differ from their ancestral reptiles lineage?
Pelycosaurs have a single temporal opening. Their reptile lineage had two.
83
What are some physical characteristics about pelycosaurs?
- Still had a sprawling posture
- Some had a broad "sail" along the back made of extended neural spines and skin.
*They used sails for thermoregulation, and possibly mating, but it's difficult to know for sure.
84
Cynodonts are currently existing mammal-like reptiles. True or False?
False. They are extinct mammal-like reptiles.
85
What are some changes in the cynodonts jaw that allowed chewing in multiple directions?
- Adductor differentiates into masseter and temporalis muscles
- Muscles expand and invade larger areas of the skull roof bones
86
Compare the occipital condyles and hindlimbs of pelycosaurs and cynodonts.
Pelycosaurs:
- One occipital condyle (like reptiles)
- Hindlimb is still far out from body
Cynodonts:
- Mammal-like double condyles (greater neck mobility)
- Hindlimb is modified to a semi-erect position closer to the body (greater stride length)
87
What do cynodonts use nasal turbinates for?
They use nasal turbinates for regulation of heat and water exchange.
88
What is the significance of a secondary palate evolving in cynodonts?
- Division of food and air passages by secondary palate
| * Means you can eat and breathe at the same time.
89
Give a few characteristics of the first mammals. (Time period, diet, thermoregulation, parental type)
- Arose in late Triassic (~210 mya) from cynodont ancestor (beginning of continental drift)
- Small insectivores displaying agile, rapid movements -Endothermy with enlarged brain for better hearing and smell
- Feed young milk from mammary glands
- Extended parental care of young
90
Early mammals had a large brain relative to their body size. True or False?
True.
91
What kind of complex integumentary glands did mammals have? Give a brief description/ function of each.
1. Sebaceous
- alveolar glands
- oily/waxy secretion often with hair
- waterproof hair and protect skin from drying
2. Sweat
- tubular
- osecrete water, salts, urea
- some important for thermoregulation
92
What kind of specalized glands arose from sebaceous/ sweat glands in mammals?
1. Mammary glands:
- Develop along the milk line during embryonic development
- Number and location of nipples varies across species
- Provide nutrition for young offspring
2. Scent glands:
- Defense, sexual recognition
93
Claws, hoofs, nails, horns, antlers, and hair in mammals are derivatives of the _______.
Claws, hoofs, nails, horns, antlers, and hair in mammals are derivatives of the INTEGUMENT.
94
Hyomandibula bone (_______ (Hint: number) branchial arch) supports jaws in fishes.
Hyomandibula bone (SECOND branchial arch) supports jaws in fishes.
95
Hyomandibula becomes the ________ in amphibians –sound transmission in middle ear
Hyomandibula becomes the STAPES in amphibians –sound transmission in middle ear
96
Jaw articulation between _________ (upper) and _______ (lower) in bony fishes, amphibians, reptiles and birds.
Jaw articulation between QUADRATE (upper) and ARTICULAR (lower) in bony fishes, amphibians, reptiles and birds.
97
In mammals, the lower jaw is now made up of a single bone called the ______.
In mammals, the lower jaw is now made up of a single bone called the DENTARY.
98
Jaw joint in mammals is between the dentary and the _______.
Jaw joint in mammals is between the dentary and the SQUAMOSAL.
99
In mammals, what are the quadrate and articular now a part of?
They are now a part of the middle ear.
100
What bones make up the middle ear of a mammal?
| 3
1. Stapes: was hyomandibula in fish
2. Incus: was quadrate
3. Malleus: was articular
101
Mammals have teeth with specialized functions. What are these teeth called?
1. incisors,
2. canines,
3. premolars
4. molars
102
Mammal dentition can tell us a lot about a mammals diet. True or False?
True.
103
Mammals arose in the late Triassic (~210 mya). What are the traditional and modern views about their evolution in regards to the K-T extinction?
1. Traditional view:
- Early mammals were small shrew-like animals
- A few lineages existed in specialized ecological niches amongst the dominant dinosaurs
- Evolved into diverse lineages after extinction of the dinosaurs (niches became available)
2. More recent ideas:
- Mammals started to diverge beforethe K-T extinction!
104
What is the association between the loss of dinosaurs and the diversification of mammals?
Increased diversification of mammals after loss of dinosaurs.
105
Did true mammals remain as small insectivores amongst the dominant dinosaurs without diversification into other lineages?
No! Many diversification events but often unsuccessful.
106
What are the three groups of living mammals? Give a brief description of each.
1. Monotremes
- Mammalian characteristics of hair, endothermy and suckling of young
- Lack nipples and external ears
- Embryos develop in leathery eggs (primitive amniote character)
- Limited diversity
2. Metatherians (marsupials):
- Found predominantly in Oceania (~200 species)
- Give birth to tiny young who suckle until they grow much larger, often in a specialized pouch of the mother
- ~100 species in the Americas, only one in North America (Virginia opossum)
3. Eutherians (plancentals):
- Most diverse and widespread group of mammals
- Radiated extensively after the KT extinction but limited diversification during last 50 my!
- Prolonged gestation of embryo in uterus with placenta
107
What does the development of embryos in leathery eggs of monotremes suggest?
Suggests earlier mammals also laid eggs.
108
The duck-billed platypus and four species of echidnas (spiny anteaters) in Australia/New Guinea are part of what group of mammals?
Monotremes.
109
What caused the strange distribution of Placentals?
-Distributions correlate with isolation of continents as they drifted away from the earlier supercontinent (Pangea)
110
Where did placentals and marsupials likely arise before the continental drift?
Placentals: likely arose in Asia --> migrated to africa --> into north and south america
Marsupials: likely arose in what would become north america
111
How did marsupial migration cause its diversity?
Mostly found in south america and australia.
- Got into south america due to physical connection of continents
- South american group is genetically different from australian group because they went on their own evolutionary paths after separation (convergent evolution)
112
How did Placentals get back into europe/asia around 30mya?
Africa collided with Europe/Asia ~ 30 mya so some species became located on those continents
113
What are some characteristics of primates?
| body, brain, offspring and parenthood, lifespan
- Large brain-body size ratio
- Long period of development and enhanced parental care
- Only one offspring (usually)
- Delayed sexual maturity
- Long life-span
114
What characteristics make primates agile in trees?
- Grasping hands/feet, opposable thumbs/ toes
| - Sensitive finger pads and flat nails
115
What are some possibilities that led to the extensive adaptive radiations of mammals?
- Extended parental care
- Greater intelligence
- Versatile feeding mechanisms (dentition)
- Locomotory adaptations
*Could have been any combination of adaptations that promoted radiation into new terrestrial niches more quickly than reptiles, birds, or amphibians.
116
Some amphibians have external gills. True or False?
True.
- Salamander larvae and some adults (paedomorphosis)
- Typical anuran larvae have external gills briefly after hatching
- Resorbed/ internalized (frogs)
117
Amphibian gills are homologous to fish gills. True or False?
False. They are not homologous.
118
What is cutaneous respiration and how is it used in amphibians?
Cutaneous respiration --> respiration through the skin
- Low keratinization of skin required for efficient gas exchange, but low keratinization = water loss in air
- To maintain integument need water/ moisture
- Need blood capillaries close to surface of exchange and increased surface area
119
How do amphibians increase surface area of their skin?
- Having wrinkles
- Having capilli on skin
*Tiger salamader --> doesn't use respiration to get rid of CO2, uses skin
Lungless salamander --> doesn't use lungs at all, uses cutaneous respiration for all gas exchange
120
How does the tetrapod lungs change depending on body size and metabolic rate?
Generally, tetrapods have paired, high surface-to-vollume ration, joined to the gut by the trachea.
They trend toward increased compartmentalization associated with icnreased body size and metabolic rate.
121
What kind of repiration system do amphibians have? How does it work?
Amphibians have a buccal pump respirational system (2 step).
1. Inspiration:
- buccal cavity expands (negative pressure)
- air is drawn into buccal cavity from outside and lungs
2. Expiration:
- Buccal cavity contracts (causes positive pressure)
- Air is forced out of nostrils
- air is forced into lungs (some mixing)
*air is forced into lungs with positive pressure
122
What kind of respiratory pump do amniotes use? How does it work?
Amniotes use aspiration pump.
1. Air is sucked into lungs because of negative pressure
- pull ribs out, increase area in lungs, negative pressure in lungs pulls air in
- Ribs and intercostal muscles power the pump in most reptiles
- Diaphragm muscle and rib cage participate in lung ventilation in mammals
123
What kind of respiratory pump do birds use? How does it work?
Birds use an aspiration pump, where lungs are coupled with air sac system, creating a unidirectional flow.
1. Air flow in the lung is:
dorsobronchus--> parabronchus--> ventrobronchus, but complex network of air sacs is involved
•Gas exchange occurs in small capillaries in the walls of the parabronchi
124
Explain the two cycle breathing in bird lungs.
1. Inhalation into posterior air sac --> exhalation over parabronchi
2. Inhalation over parabronchi & into anterior air sacs --> contaction of anterior air sacs to compress air out of them and into the bronchi (lung)
125
Explain each step of the bird lung ventilation.
```
Inhalation #1:
outside --> posterior air sac --> top part of lung
Expiration #1:
posterior air sac --> profuses lung --> parabronchi
Inhalation #2:
leaves parabronchi --> anterior air sacs
Expriation #2:
anterior air sacs --> outside of body
```
126
What kind of respiratory flow do fish, birds, frogs, and platypus have?
(Uni, bi)
Fish --> unidirectional
bird --> unidirectional
frogs --> bidirectional
platypus --> bidirectional
127
What kind of airflow is more efficient? Why?
Unidirectional air/water flow is more efficient.
| This has to do with the physical relationship between the air medium and the blood supply (gas transfer of O2)
128
What kind of gas transfer at the respiratory surface do mammals have?
Mammals have a uniform pool gas transfer:
| Blood encounters relatively constant gas concentrations
129
What kind of gas transfer at the respiratory surface do birds have?
Birds have a cross-current exchange system.
| Blood encounters increasing gas concentrations allowing progressive loading of oxygen.
130
What kind of gas transfer at the respiratory surface do fish have?
Fish have a countercurrent exchange system.
Blood first encounters lower gas concentrations and is fully equilibrated with oxygenated water.
The tube that carries water & the tube that carries blood are very thin; causes a big gradient that maximizes O2 exchange.
131
How many times does the blood pass through the heart per circulation in tetrapods?
Twice.
1. To/from body --> systemic circulation
2. To/from lungs --> pulmonary circulation
132
How many chambers does the anuran heart have?
3. Two atria, one ventricle
133
Similar to mammals, anurans oxygenate their blood through their lungs. True or False?
False. Some anuras are able to oxygenate their blood through their skin by pulmocutaneous artery.
Then they will take the oxygen rich blood from the skin to the body.
134
In anurans, oxygen poor blood from the body enters the ______ atrium, enters ventricles, and then goes to the lungs by pulmonary arteries.
In anurans, oxygen poor blood from the body enters the RIGHT atrium, enters ventricles, and then goes to the lungs by pulmonary arteries.
135
In anurans, pulmonary veins carry oxygen-rich blood from the lungs to the ______ atrium.
In anurans, pulmonary veins carry oxygen-rich blood from the lungs to the LEFT atrium.
136
What is the function of the conus in anurans?
Conus arteriosus is partially divided by the spiral valve. It guides the blood flow towards the systemic and pulmocutaneous routes.
137
How many chambers do reptiles have in their hearts?
3. 2 atria, 1 ventricle.
| BUT the ventricle is partially divided by a septum.
138
How many vessels come out of the left side of the heart in reptiles?
2 aortic (systemic) vesself from the left side to the body and the head.
139
How does the flow in the reptile heart change when it's under water?
- Most blood bypasses lungs
| - Gap between ventricles allows deoxygenated blood to leave heart via left aorta rather than pulmonary artery
140
How are the hearts of birds and mammals similar?
They are very similar in the way that they both have 4 chambers with similar designs and flow.
Difference: systemic arch to body & head in mammals --> left side; in birds --> right side
141
Give a flowchart of the circulation in adult mammals.
Right atrium --> right ventricle --> lungs --> left atrium --> left ventricle
142
How does the uptake of nutrients/ oxygen change in fetal circulation of mammals?
- Uptake of oxygen and nutrients occurs at placenta
| - Need to shunt most of blood away from developing lungs and into systemic circulation
143
Fetal circulation in mammals has two bypasses? What and where are they?
Bypass 1:
Blood enters right atrium and exits through foramen ovale --> left atrium and left ventricle --> head and upper body
Bypass 2:
Remaining blood enters right ventricle --> enters pulmonary artery, travels through ductus arterious --> lower body and placenta to be oxygenated
•Both close off at birth
144
Why do fetal mammals have two bypasses in the circulatory system?
Need two bypasses just in case one doesn't work.
ex. no foramen ovale --> would somehow need to get blood to the left ventricle, you would only be getting blood to the head.
145
What does the ductus venosus do in fetal mammals?
It aids the blood in bypassing the liver.
Takes blood from the placenta:
- some to liver
- Rest to inferior vena cava --> heart --> right atrium --> some to foramen ovale, lots to ventricle --> ductus arteriosus
146
How many aortic arches do lamprey, hagfish, bony fish, and teleosts have?
Lamprey --> 8 pairs
hagfish --> 15 pairs
bony fish --> 4 pairs
Teleosts --> fewer
147
How many aortic arches do vertebrate embryos have?
6 arches.
148
How many aortic arches do teleosts have?
4 arches (3-6)
149
How many aortic arches do lungfish have?
5 arches (2-6)
150
How many aortic arches do amphibians have? (Give evolutionary history)
3 arches.
3= carotids to head
4 = systemic on both sides; single vessel from heart splits in two
6 = pulmonary to lungs
151
How many aortic arches do reptiles have? (Give evolutionary history)
3 arches. (3, 4 and 6)
| -4 found on both sides with separate vessels from heart
152
How many aortic arches do birds have? (Give evolutionary history)
3 arches. (3, 4 and 6)
| -4 only on right side
153
How many aortic arches do mammals have? (Give evolutionary history)
3 arches. (3, 4 and 6)
| -4 only on left side
154
What are the 5 main functions of the digestive system?
1. receives
2. stores
3. Breaks down (chemically and physically)
4. absorbs
5. discharges (undigested waste)
155
What are the 4 main components of the digestive tract?
1. Mouth
2. Pharynx
3. Tubular parts (alimentary canal):
- esophagus
- stomach
- intestine (small and large)
4. cloaca/ rectum
156
Give a small evolutionary history of "mouths".
| ancestral vertebrates, agnathans, fishes
- Ancestral vertebrates --> likely filter feeders with small mouths
- Agnathans--> have no jaws or true teeth and a small buccal cavity
- Fishes--> have highly specialized mouths with firm tongues
157
What are teeth derived from?
-derived from bony dermal armor/ similar structure to placoid scale
158
What are teeth composed of?
Composed of dentin, covered by a crown of enamel
159
What are the different attachment types of teeth?
1. acrodont dentition:
- teeth attached to the outer surface or to the summit of the jawbone
- many teleosts
2. pleurodont dentition:
- attached inner side
- anurans, salamanders, many lizards
3. thecodont dentition:
- teeth occupy bone sockets or alveoli
- some fishes, crocodilians, fossil birds, mammals
(14, slide 7)
160
What are the different types of teeth?
+What kind do mammals have?
(Hint:2)
1. Homodont--> teeth all the same size and shape
2. Heterodont--> teeth vary morphologically
Mammals: Heterodont dentition with species-specific number of teeth (evolved along with ability to chew)
161
How do birds mechanically break down their food, considering they have no food?
They have a gizzard inside their stomach.
162
What is the importance of having salivary glands (primarily for mammals)?
It allows chemical digestion to begin as soon as the food enters the mouth.
163
Are salivary glands found in fishes and tetrapods?
Only found in tetrapods, not fishes.
164
What are the functions of the salivary glands?
| 3
- Primary is to moisten the food for lubrication
- Allows tongue to be sticky to assist prey capture (frogs and anteaters)
- Allows start of starch digestion (some mammals)
165
How are salivary glands modified in snakes & lizards, and birds & reptiles?
- Modified into poison glands in some snakes and lizards
| - Moved to near orbits in marine reptiles and birds and functions for salt excretion
166
The esophagus is a muscular tube that leads from the _______ to the ______. It is rich in mucous glands.
The esophagus is a muscular tube that leads from the PHARYNX to the STOMACH. It is rich in mucous glands.
167
How is the esophagus modified in birds?
Modified into crop in some birds –storage of grain
168
The stomach is a muscular chamber that begins at the end of the esophagus and terminates at the _________.
The stomach is a muscular chamber that begins at the end of the esophagus and terminates at the PYLORUS.
*pylorus is surrounded by the pyloric sphincter (ring of smooth muscles); it controls the passage of food to the intestine
169
What do the gastric glands of the stomach produce? How is this beneficial?
Gastric glands in the stomach produce hydrochloric acid that help with chemical breakdown of food.
170
The stomach is greatly involved in the absorption of food. True or False?
False. The stomach's main function is the breakdown of food (has little absorption).
171
What are two special features of the bird (and crocodile) stomach?
1. Glandular proventriculus:
- Secretes digestive enzymes
2. Muscular gizzard (ventriculus):
- tough horny layer for grinding and mixing food with gastric secretions.
172
Some mammals have modifications in their stomach with 4 compartments. What are these compartments and what is their function?
1. rumen:
- stores and churns;
- residence for bacteria, which produce cellulase (no vertebrates can produce the enzyme themselves).
2. Reticulum:
- receive food from rumen and form cud,then regurgitate for further chews
3. Omasum:
- temporary holding site
4. Abomasum:
- the only place with gastric gland (chemical breakdown)
173
Secretion of mucus and digestive enzymes, other enzymes secreted into the _______ from liver and pancreas.
Secretion of mucus and digestive enzymes, other enzymes secreted into the INTESTINE from liver and pancreas.
*Usually emptied into the duodenum.
174
What are the roles of the small and large intestine?
Small intestine--> main site of digestion and absorption of nutrients
Large intestine--> mostly recovers water, but can be used for fermentation
175
"Gut morphology is flexible to functional adaptation." Explain.
Storage, fermentation, length of track is correlated with eating habit and diet, and NOT so much constrained by evolutionary history.
176
How are the guts of herbivores and carnivores different?
Herbivores--> long guts with intestinal specializations that promote fermentation (e.g., caecum, large intestine, stomach)
Carnivores--> shorter, relatively unspecialized guts
177
What are the layers of the gut wall (outside to inside)? Give a brief description of each.
(4)
1. Serosa--> connective tissue and mesentery
2. Muscularisexterna--> two layers of smooth muscle
3. Submucosa--> connective tissue, autonomic nerves
4. Mucosa--> epithelial lining, smooth muscle fibres, connective tissue
178
What are three strategies that the gut uses to increase surface area?
1. Caeca:
- blind-ended (closed at one end) extensions of gut, can come out in various places (pyloric caeca, colic caeca, etc)
- Function: digestion/ absorption in fishes, fermentation in some mammals
2. Spiral valve:
- (chondrichthyans, lungfish)
- Forces passing food through a spiral route, increasing path length
3. Foldings:
- (tetrapods)
- Large surface area is achieved by coils of the canal, folds, villi, and microvilli on the internal surface
179
What are the main functions of the excretory system?
- Remove nitrogenous wastes and other harmful substances
| - Control osmosis to achieve water and salt balance
180
What are the organs involved in the excretory system? (all animals)
Organs involved:
| kidney, gills, skin, part of the digestive system, salt glands
181
What is the main function of the reproductive system?
- Produce and release gametes, bring them together
| - Provide nourishment to young
182
What are the organs involved in the reproductive system? (all animals)
Organs involved:
| gonads, ducts, cloaca, copulatory organs
183
How do the kidneys develop?
- Development moves from anterior to posterior in three sections with breaks in between
- Anterior, middle, and posterior kidneys form in sequence
- Anterior regions usually degenerate as posterior regions become functional
- More posterior break may not form so that two instead of three pairs of kidneys are formed in sequence
184
The first 4 segments of the kidney is called the _________.
The first 4 segments of the kidney is called the PRONEPHROS.
185
What are 2 characteristics of the pronephros?
1. Appears in all vertebrates (rudimentary form) but degenerates quickly
2. Functional in fish larvae and adults of hagfish and some teleosts
186
What is a "head kidney" and what is its function?
"Head kidney" --> degenerated pronephros
| -Has hemopoietic, lymphoid and endocrine functions
187
The opisthonephros and mesonephros have more segmentation than the pronephros. True or False?
False.
188
What animals have opisthonephric kidneys?
- Adult fishes and amphibians have an opisthonephric kidney
| - Developing amniotes develop a mesonephros that degenerates
189
The metanephros is the kidney of _______.
The metanephros is the kidney of AMNIOTES.
190
Similar to the pronephros, the metanephros is segmented. True or False?
False. The metanephros is unsegmented.
191
The metanephros replaces the ______ that arose earlier in development.
The metanephros replaces the MESANEPHROS that arose earlier in development.
192
What happens to the old mesonephric duct in amniotes when the kidney becomes metanephric?
Females: Old mesonephric duct degenerates
Males: persists to carry sperm
*Metanephric kidney is drained by a new duct: the ureter.
193
What is the nephron and what does it consist of?
```
Nephron = functional unit of the kidney
nephron = renal corpuscle + nephric (renal) tubule
```
194
How does waste come out of the pronephric kidneys?
Waste forced out of the blood --> into coelom --> picked up by nephric tubule
195
What does the renal corpuscle in mesonephric/ opitsthonephric kidneys consist of?
(2)
1. Glomerulus = cluster of capillaries (external or internal)
2. Renal or Bowman’s capsule = cup like sack that collects urine
196
What are the two sources from which gonads develop?
1. Mesomere genital ridges
- become supporting tissues of gonads (sex cords)
2. Primordial germ cells
- become gametes
- arise from endoderm and migrate to genital ridge early in development
197
All vertebrates (except cyclostomes) have a pair of nephric and Muellerian ducts and possibly others. True or False?
True.
198
Cyclostomes have no sexual ducts. True or False?
True.
-Eggs and sperms are released into the coelom, exit into cloaca by way of genital pores.
199
What are the principle urogenital ducts?
| 4
- Nephric ducts (pro, meso, opistho)
- Muellerian ducts
- Ureter
- Accessory ducts
200
Variation in urogenital ducts among groups is the result of the _______, _____or _______of the basic structure.
Variation in urogenital ducts among groups is the result of the RETENTION, LOSS or MODIFICATION of the basic structure.
201
What happens to muellarian ducts in males?
They regress.
202
What is the function of the efferent ductules and nephric duct in males?
- Efferent ductules--> carry sperm from testis to nephric duct
- Nephric duct--> can carry sperm or urine or both depending upon organism
203
The male urogenital system is a closed system. True or False?
True.
204
How does the function of the nephric duct vary in sharks & amphibians compared to teleosts and amniotes (MALES!)?
Most sharks and amphibians:
- Nephric duct carries sperm
- accessory urinary duct varries urine
- *In mudpuppy, nephric duct carries both
Teleost:
- Nephric ducts for urine
- new sperm duct
Amniotes:
- Nephric duct for sperm
- Ureter for urine
205
What happens to muellerian ducts in females?
They become oviduct to carry ova.
* Except in teleosts!
- Teleost oviduct derived from ovarian folding
- Not homologous to Muellarian ducts
206
What do the opisthonephric ducts do in sharks, teleosts, and amphibians?
Opisthonephric ducts carry urine.
207
What happens to the mesonephric duct in female amniotes?
- Mesonephric duct degenerates
| - Ureter carries urine
208
What kind of system is the female reproductive system?
Open system: egg --> body cavity --> oviduct
209
What is the function of the nervous system? (along with the endocrine system)
The nervous system (along with endocrine system) --> determines response of the body to changes in its environment
*Has a sensory-motor integration system
210
What types of cells does the nervous system use?
1. Neurons
| 2. Glia (neuroglia)
211
How can neurons be classified?
Can be classified according to:
1. function --> (sensory, motor, interneuron)
2. morphology --> (unipolar, bipolar, multipolar)
212
Cell body (_____) of the neuron usually bears one or more _______ to receive information and usually one _____ to transmit impulses (action potentials).
Cell body (SOMA) of the neuron usually bears one or more DENDRITES to receive information and usually one AXON to transmit impulses (action potentials).
213
What is the main function of neuroglia cells? Give a few examples.
Main function: protection and support.
Examples:
- Schwann cells--> insulate axons with myelin
- Astrocytes--> pass nutrients between capillaries and neurons
- Microglia--> engulf foreign material
214
What is a synapse and what is its function?
Synapse: connection between an axon of one neuron with a dendrite/ nerve cell body of another neuron.
Function: Directional transmission of signal from one neuron to another (synaptic transmission)
215
The nervous system is composed of two systems. What are they?
1. Central nervous system (CNS)--> brain and spinal cord
| 2. Peripheral nervous system (PNS)--> everything else
216
What is the difference between the CNS and the PNS when it comes to bundles of fibers and the group of cell bodies (soma)
Bundle of fibers:
- CNS --> tract
- PNS--> nerve
Group of cell bodies (soma):
- CNS--> nucleus
- PNS--> ganglion
217
Whaat is the organ that coordinates all of the activities of an organism?
The brain.
218
What are the functions of the spinal cord in the CNS?
| 4
- receive incoming impulses
- Integrate and coordinate them
- transmit them wherever they should go within the CNS,
- send responses to the PNS as appropriate
219
What are the two neuron properties that the PNS is described according to?
1. What is being innervated (visceral, somatic)
| 2. Direction of signal (afferent, efferent)
220
What do somatic/ visceral mean? (PNS)
Somatic--> skeletal muscle and skin (voluntary)
| Visceral(Autonomic) --> involuntary muscles and glands
221
What are the two possible directions of signal in the PNS?
1. Afferent(sensory) --> from tissues to CNS
| 2. Efferent (motor) --> from CNS to tissues
222
What are spinal nerves?
Spinal nerves --> Nerves associated with spinal cord segments
223
What are the two roots of the spinal nerves? Give a brief description of each.
1. Dorsal root:
- Contains sensory neuron fibres (somatic and visceral)
- Contains cell bodies clustered in ganglia
2. Ventral root:
- Contains motor neuron fibres (somatic and visceral)
- Cell bodies of motor neurons are in spinal cord (clustered in nuclei)
224
Spinal nerves are segmented. True or False?
True.
225
What are the grey and white matter of the spinal cord?
- Gray matter: cell bodies of motor neurons and unmyelinated fibers (location of synapses)
- White matter: myelinated fibers (axons)
226
What are cranial nerves and what is their function?
Cranial nerves --> Nerves that emerge directly from the brain (including the brainstem) rather than spinal cord
-Function: Relay information between the brain and parts of the body
227
What are the main differences between the mammal and the lamprey spinal nerves?
- Mammals: dorsal and ventral fibers join together where visceral motor nerves leave the ventral root
- In lampreys: visceral motor nerves exit the dorsal root
228
What makes up the visceral (autonomic) nervous system? What is this system?
Visceral nervous system --> Division of PNS that controls visceral organs, monitors their internal environment and activity
(takes signal from CNS--> organ)
Made up of:
- Cardiac and smooth muscles,
- urogenital system,
- pigment cells,
- some respiratory organs,
- intrinsic eye muscles
- glands
229
Visceral motor fibers are divided into two sets. What are they and how do they differ?
1. sympathetic
2. parasympathetic
- Anatomically distinct
- Cause antagonistic responses in organs
230
How many neurons carry efferent signals in visceral system vs somatic system?
Efferent signals relayed by:
Visceral system = 2+ neurons
Somatic system= 1 motor neuron (spinal nerve)
231
What are the relative sizes of preganglionic and postganglionic fibers in sympathetic and parasympathetic systems?
Sympathetic:
- Short preganglionic fiber
- Long postganglionic fiber
Parasympathetic:
- Long preganglionic
- Short postganglionic
232
What is the function of the sympathetic nervous system?
| How are the ganglia linked, and what kind of flow is it?
- Prepares body for stressful situation
- expands energy: alertness, excitement, alarm, the ‘fight or flight response’
- Ganglia in a chain
- Preganglionic cell comes our in a thoracolumbar outflow
233
What is the function of the parasympathetic nervous system?
| How are the ganglia linked, and what kind of flow is it?
Slow down: ‘rest/digest’
- ganglia close to organ (usually in a cluster near the muscle they're innervating)
- Craniosacral outflow
- Often more postganglionic neurons than preganglionic
234
Why does the parasympathetic nervous system have more postganglionic neurons than preganglionic neurons?
1. When you're responding to a situation where you need to shut some organs down, you need to calm multiple places
- Requires broad responses
2. Want a coordinated response, fastest thing to do is to have branches of some long post ganglionic cells
- Makes it more efficient and coordinated
(Some things are ramped up, some things are ramped down)
235
What are the main to aspects concerning the evolution of the brain?
1. Enlargement of the cerebrum
- Higher functions
2. Enlargement of the cerebellum
- regulates motor movements
*Bony fish have large optic tectum
236
The expanded abilities to taste in the goldfish and catfish are associated with the expansion of what parts of the brain?
1. Hindbrain vagal (VL)
| 2. Facial lobes (FL)
237
Electrosensory abilities of the glass knifefish involve the expansion of what part of the hindbrain?
1. Lateral line lobes (EL) of the hindbrain
238
What do mormyrid fishes use their electric sense for?
They use if for life in turbid waters.
239
What is the function of sense organs?
- Perceive and integrate sensation
| - Initiate action
240
What are the two main types of chemoreceptors in animals?
1. Olfactory organs
| 2. Taste organs
241
Give a few characteristics of the olfactory organs.
- ectodermal in origin
- Olfactory epithelium located in the nasal pit or respiratory passage
- Filaments serve to increase surface area
- Olfaction used for discrimination of chemicals in the environmen
242
Compare the olfactory regions in fish, air-vertebrates, tetrapods, and mammals.
- Fish: water into nasal pit
- lamellae made up of olfactory epithelium and support tissue
- Air-breathing vertebrates: add mucous cells to dissolve the particle and wash away old samples
- Tetrapods: size and complexity of nasal chamber increased
- Mammals: complex turbinate (scrolls of bone); distinguish trillions of odours!
243
Give a few characteristics of taste organs.
Function: detect similar molecules with similar structure as the olfactory organs but differ in:
- less sensitive
- receptor cells aggregated into taste buds
- associated with afferent sensory fibers from cranial nerves rather than having their own axons (not hard wired)
- exposure -worn and replaced (large cell turnover)
244
How do photoreceptors work?
- Cells are capable of phototransduction (generate electrical potention with photon absorption)
- Photoreceptor neurons are organized into the complex epithelium of the retina in eyes
245
The retina is made up of two receptor cells that detect light. What are they called and what is their function?
1. Rods --> light sensitive, no colour
| 2. Cones--> colour
246
Path of light entering the eye is converted to electrical signal and relayed to the ______ nerve.
Path of light entering the eye is converted to electrical signal and relayed to the OPTIC nerve.
*The brain then translates the signals into an image.
247
Taste organs are surrounded by supporting cells. True or False?
True.
248
Index of refraction of water is the same as inside eye and _____, but index of refraction of _____ is above that of water.
Index of refraction of water is the same as inside eye and CORNEA, but index of refraction of LENS is above that of water.
249
How do animals focus their eyes when they go into water?
-They change the lens position by contraction of the retractor lentis muscle.
250
Is the cornea involved in the focusing of light?
No. The cornea is flat.
251
Index of refraction of air differs from inside the eye and _____.
Index of refraction of air differs from inside the eye and CORNEA.
252
How do animals focus their eyes on land?
change in lens shape by relaxation of ciliary muscle (attaches suspensory ligaments between eye and lens).
*+Cornea is rounded so also involved in focusing light.
253
How do animals adapt to dim/ night light?
| 3
1. Large eyes: large pupil, large lens close to retina
2. Few cones or none, slender rod cells are closely packed
3. Tapetum lucidum (mirror) can be present (e.g. deer in the headlights)
254
What are the 4 kinds of mechanoreceptors and what kind of sensations do they have?
1. Encapsulated sensory receptors --> Light touch
2. Associated sensory receptor --> Motion sensor of hair follicle (shear)
3. Free sensory receptor --> Fine touch and temperature
4. Pacinian corpuscle --> Deep pressure
255
What is proprioception and what is its function?
Proprioception (balance/ equilibrium)
- Muscle spindles and Golgi tendon organs monitor muscle contraction and limb flexion
- Enable the brain to keep track of body position
256
What are the two components of the Lateral Line system? Give a brief description of each.
1. Mechanoreceptive component
- detects water movement
- in all fishes and larval (some adult) amphibians
- Consists of thousands of neuromasts dispersed on the body surface or inside lateral line canals
2. Electroreception component
- present in many fishes and the platypus
- detects weak electric stimuli using electroreceptors made up of jelly-filled canals leading to the skin surface
257
What system is the neuromast a part of? How does it function?
Neuromast is a part of the lateral line system.
-Water movement is measured by displacement of the gelatinous cupula
(bends the stereocilia towards kinocilium, increasing firing rate of sensory neuron)
-Neuromasts collectively provide both spatial and temporal information
258
What are the two functions of the ear and what part of the ear specializes in it?
1. Equilibrium --> vestibular system in inner ear
- Similar structure, function and development to lateral line system
- Register head position
- Detect angular acceleration of head
2. Hearing--> middle ear and cochlea
***Both functions depend on hair cell movement by for transduction of mechanical information
259
What are the three semicircular canals of the ear?
1. Anterior
2. Posterior
3. Horizontal
260
What are the two chambers of the ear?
1. Utriculus
| 2. Saccule
261
Each semicircular canal also has a sensory cell patch at its base called _____.
Each semicircular canal also has a sensory cell patch at its base called CRISTA.
*Crista ampulla picks up rotational movement and acceleration in different directions
262
Sensory cell patches in each chamber are called _____,with structure similar to neuromast.
Sensory cell patches in each chamber are called MACULA,with structure similar to neuromast.
263
The lagena can be expanded to form a cochlea. True or False?
True.
264
What are the functions of the semicircular canals of the ear?
1. Respond to rotational movements
2. Angular acceleration,
3. Position of head in 3 dimensions
265
The cupula in the ear may be modified into a solid crystal mass. What is it called?
Otolith.
266
How does hearing (in the middle and inner ear) work?
| 3
1. Tympanum (eardrum) receives airborne sound wave
2. Middle ear bones mechanically transmit the vibration to the oval window -the opening of the bony housing of inner ear
3. Motion of waves in fluid translate into shearing force over the hair cells
267
There are two mechanisms that increase the force of hearing in mammals. What are they?
1. small oval window
2. lever system of three ear bone
- Incus (Quadrate)
- Malleus (articular)
- Stapes (hyomandibular)
268
How do infrared receptors work?
Facial pits (or pit organ) have a high density of free nerve endings organized in a membrane.
*Highly specialized in snakes.
269
Muscle cells are electrically excitable. True or False?
True. Muscles are responsive to nervous stimulation.
270
What are methods to classify muscles?
| 3/4
1. By location: somatic (skeletal) and visceral (gut)
2. By method of nervous control (voluntary or involuntary)
3. By microscopic appearance (skeletal, cardiac or smooth)
4. Will use a combination of these approaches
271
What are the different microscopic appearances of muscles? Give a brief description of each. (3)
1. Smooth --> muscles of blood vessels and many visceral organs
- Not triated
- Spindle shaped
- Relatively involuntary
2. Skeletal muscle --> associated with the skeleton*
- Striated
- Cylindrical
- Voluntary
3. Cardiac--> muscle of the heart wall
- Straited
- Cylindrical
- Branched
- Intercalated disks
272
What are the three parts of the mesoderm in the embryo?
1. Somites/ epimere
- Dermatome (skin)
- Myotome (skeletal muscle)
- Sclerotome (skeleton)
2. Hypomere
- Heart & gut muscles
3. Mesenchyme
- various
273
What are the parts of the epimere?
| 3
1. Myotomes (epaxial and hypaxial)
- Most post-cranial muscles
- some cranial muscles
2. Somitomere
- Not fully segmented
- Cranial muscles
3. Hypomere
- Heart muscle
- Visceral (gut) muscle
274
Usually two groups of muscles working opposite to each other. True or False?
True.
| *Muscles are usually found in pairs.
275
Skeletal muscles are joined to bone by _______.
Skeletal muscles are joined to bone by TENDON.
276
Bones are joined together by _______.
Bones are joined together by LIGAMENTS.
277
What are the 3 major muscle groups?
1. Postcranial muscles
2. Cranial muscles
3. Muscles of the gut and heart
278
What are the types of postcranial muscles? (2)
1. Trunk (axial) musculature
- Body wall
- Divided into epaxial and hypaxial division
2. Appendicular musculature
- Fins & limbs
279
What are the types of cranial muscles? (3)
1. Branchiomeric muscles:
- jaw and pharynx muscles derived from somitomeres (innervated by cranial nerves)
2. Hypobranchial muscles:
- jaw and pharynx muscles derived from cervical somites (innervated by spinal nerves)
3. Extrinsic eye muscles
