Lecture Exam 2 Flashcards
what are the functions of ribs in amniotes?
support trunk muscles and lung ventilation
what do ribs articulate with?
transverse process
what is different about chondrichthyes ribs?
1 set of ribs
go from vertebrae to horizontal septum
what do chondrichthyes vertebrates do?
support epaxial muscles
and trunk muscles below the horizontal septum (hypaxial muscles)
what is special about seahorses?
NO RIBS
what are the ribs like in bony fishes?
connect vertebrae to myosepta of ventral body wall
support hypaxial muscles
what is special about
~some~ actinopterygii?
have 2 sets of ribs, ventral and dorsal
most only have ventral
what are the ribs in tetrapods?
1 set
bicipetal ribs
what are bicipetal ribs?
2 heads
tuberculum (transverse process) and capitulum (centrum)
what are amphib ribs like?
short
fused to transverse process
how are ribs laid out in amniotes?
2 parts: costal and sternal
what is the difference between the costal and sternal parts of amniote ribs?
costal is next to the vertebrae
sternal is ventral and attached to sternum
What is it called when sternal ribs are cartilaginous?
costal cartilage
what is the structure of ribs in birds?
bony sternal ribs
costal ribs have uncinate process (rearward projection of bone)
what is the function of bird ribs?
brace the trunk
what groups have sterna?
only tetrapods
lacking in fish
what is sterna made of and what is its function?
endochondral bone
support pectoral girdle and ribs
describe the structure of different groups sterna
amphibs: absent or poorly developed
salamanders: weak, only 1 bone
frogs/toads: more developed/stronger, 4 bones
why do frogs/toads have a more developed sterna?
land on forelimbs and need to absorb the impact
what does the sterna look like/do in amniotes?
it is well developed
allows for increased use of forelimbs in locomotion
what group lacks sterna?
snakesssss
what does the sterna look like in birds?
keeled sternum
very deep
why do birds have such specialized sterna?
for flight muscle attachment
describe the 3 birds and sterna types discussed in class?
roughed grouse (state bird): strong sterna
ostrich: flat sterna
penguins: keeled sterna
what are the parts of the cranial skeleton?
neurocranium
dermatocranium
what is the neurocranium?
brain case
what is the dermatocranium?
dorsal roof made of dermal bone
what are the parts of the visceral skeleton?
jaws
branchial arches
what is the other name for visceral skeleton?
splanchnocranium
what is the origin of the neuro and splanchnocranium?
originate as cartilage and are replaced by endochondral bone
what does the neurocranium in cyclostomes look like?
basal plate and sensory capsules
lacks a “roof” covering
remains cartilage
what does the neurocranium look like in chondrichthyes?
cartilage (chondrocranium)
has occipital condyles that articulate cranium with vertebral column
what are the ossification centers of the neurocranium?
occipital
sphenoid
ethmoid
otic
*no dorsal replacement bone
what is occipital ossification?
bones around the foramen magnum ossify
how does occipital ossification work in mammals? in bats?
mammals: fuse into occipital bone
in cats: basioccipital remains separate
what is sphenoid ossification?
under midbrain, presphenoid and basisphenoid ossify
which “sphenoid” does not come from the sphenoid ossification center?
alisphenoid
comes from palatoquadrate
what happens to the presphenoid and basisphenoid in some mammals?
fuses into a single bone called the sphenoid
what is ethmoid ossification?
it is cartilaginous in tetrapods
ossifies everything but the terbinals
what are terbinals?
highly coiled bone in the nasal cavity with a moist epithelial surface
what animals have terbinals and what do they do?
sauropsids and mammals
play a role in olfaction (olfactory terbinals) and conserving heat and H2O
what is otic ossification?
involves several bones and lots of fusion (especially in birds/mammals)
which bones fuse in otic ossification?
otic bones fuse into the petrosal
petrosal and squamosal fuse into the temporal bone
what are the roofing bones in the basic dermatiocranium?
series of many paired bones in the middorsal area (frontals and nasals), around the orbit (jugals) and at the posterior angle of the skull (temporal)
what are the jaw bones in the basic dermatocranium?
the toothbearing bones: premaxilla and maxilla
what are the parts of the primary palate in the basic dermatocranium?
single parasphenoid
several paired bones (palatine)
covered by secondary palate in later tetrapods
what are the opercular bones?
make up operculum
cover gills
what is the function of the operculum?
protection and ventilation of gills (pumps water through)
what are the parts of the opercular bones and which group lacks them
absent in tetrapods
opercular bone, pre-, sub-, inter-operculars
what does the neurodermatocranium complex look like in bony fish?
laterally compressed
fully ossified neurocranium (except olfactory capsule)
what is the benefit of the laterally compressed neurodermatocranium complex in bony fish?
allows for streamlined shape to move through water
what does the neurodermatocranium complex look like in amphibs
dorsoventrally flattened
what are the neurocranial features of the neurodermatocranium complex of amphibs?
some cartilage
what are the dermatocranial features of the neurodermatocranium complex in amphibs
bones of orbit and temporal region lost
otic capsule exposed
large palatal fenestra
why is the amphib neurodermatocranium complex so weird?
because frogs/toads can retract their eyeballs into the oral cavity to help them swallow prey
what does the neurodermatocranium complex look like in amniotes?
major developments of the temporal fenestra and a secondary palate (in some)
whats special about turtles
they have a loss of dermal bone at the posterior which serves the same function as temporal fenestra (which turtles lack)
what is the loss of dermal bone at the posterior of the neurodermatocranium complex of turtles called?
emarginated posterior
what is the function of temporal fenestra?
increases surface area of skull for jaw muscles/attachment, space for bigger jaw muscles, allows reorientation of jaw muscles to improve jaw mechanics
what does a synapsid neurodermatocranium complex look like?
lateral temporal fenestra with a low border (zygomatic arch)
made up of 2 bones: jugal (zygomatic) and squamosal (temporal)
what does a diapsid neurodermatocranium complex look like?
2 temporal fenestra (an infratemporal and a supratemporal) with a lower arch made up of the zygomatic (jugal and squamosal) and an upper arch of the supratemporal (squamosal and post orbital)
what does the neurodermatocranium complex look like in squamates and birds
1/2 arches are lost secondarily to improve flexibility, allows for cranial kinesis
what is cranial kinesis?
movement of one part of “skull” independent from the rest of skull to increase feeding opportunities (eat larger prey)
how are snake skulls different for feeding?
lower jaw can spread laterally, 2 sides move independently, can also move trachea so able to breathe while eating
what is the secondary palate and its use
divides oral cavity
consists of nasal and oral passages and the internal nares (run caudally)
what groups have a complete secondary palate?
crocs and mammals
what is the structure of the secondary palate in crocs and mammals?
crocs: completely bone
mammals: caudal part is fleshy
why is the secondary palate important?
for eating and breathing at the same time
what does the neurodermatocranium complex look like in mammals?
its incomplete in infants, it creates fontanels
what are fontanels and their function?
membraneous spots between dermal bones
allows skull to have flexibility to come through birth canal
what does the visceral skeleton of cyclostomes look like?
branchial basket made of cartilage
lingual cartilage
labial cartilage
what does the branchial basket do in cyclostomes?
supports gills (not true gill arches)
what does the lingual cartilage and labial cartilage do in cyclostomes?
supports tongue
supports buccal funnel
explain the structure of the shark splanchnocranium
7 arches
#3-7 support the gills (branchial arches)
#1-2 modified for feeding
explain the first and second arches of the shark splanchnocranium that are modified for feeding
1: mandibular arch made up of palatoquadrate and Meckel’s cartilage
2: hyoid arch made up of basihyal, ceratohyal, hyomandibular
what are the repeating units of arches 3-7 in the shark?
basibranchial
hypobranchial
ceratobranchial
epibranchial
pharyngobranchial
describe the holostylic jaw suspension
palatoquadrate firmly attached to neurocranium
jaw joint is the palatoquadrate and Meckel’s cartilage
UPPER JAW IMMOBILE
what is the other term for holostylic?
autostylic
what groups have holostylic jaws?
ancestral jawed fish
secondarily evolved in ratfish
describe the amphistylic jaw suspension
the joint is the palatoquadrate, Meckel’s cartilage and the hyomandibula with the palatoquadrate and hyomandibula braced against the neurocranium
LITTLE MOBILITY
what groups have amphistylic jaw suspensions?
ancestral sharks
describe the hyostylic jaw suspension
joint is the palatoquadrate, meckel’s cartilage and hyomandibula
only hyomandibula braced against cranium
GREATER UPPER JAW MOBILITY AND INCREASED CRANIAL KINESIS
what groups have hyostylic jaw suspensions?
derived sharks through tetrapods
upper jaw will become bone (or covered by bone) and fixed in most tetrapods
describe bony fish jaws
ensheathed by dermal bones
posterior ends replaced by endochondral bones (quadrate and articular)
what changes about the jaw joint in bony fish?
now between quadrate, articular and hyomandibula
describe the hyoid and branchial arches in bony fish
ossify with endochondral bone (branchial)
hyoid adds multiple additional elements
which shark is known for its upper jaw protrusion?
goblin shark
how does upper jaw protrusion work?
the pre maxilla is mobile and the operculum spreads laterally
how is the pre maxilla mobile in groups with upper jaw protrusion?
leverage from lower mandible and maxilla to push pre maxilla out and forward as lower jaw opens
what does the operculum spreading laterally cause?
1: increase in volume of buccal cavity to create suction
2: draws in water for aiding in capturing prey and improving ventilation of gills and efficiency of gas exchange
describe the lower jaw in tetrapods
more dermal bones in some early tetrapods cartilage remains only in crocs and turtles
same jaw joint just without hyomandibula
describe the tetrapod hyomandibula
ossifies to become columella (stapes), basic tetrapod condition except for in mammals
what is the stapes?
middle ear bone that transmits sound waves from tympanum to inner ear
what jaw modifications do tetrapods have?
articular quadrate hinge
what jaw modifications do mammals have?
denture expands on the squamosal joint
what do the postdentary bones develop into?
ear bones:
hyomandibula–> stapes
quadrate–> incus
articular –> malleus
why do mammals have a large denture and jaw muscles?
for chewing
why do the post denture bones turn into ear bones?
post denture bones were already used for hearing
increased dentary for muscles not compatible
bones separate to increase hearing ability
what do the hyoid and branchial arches turn into in tetrapods?
highly modified bones, most of which support the tongue or larynx (voicebox) in mammals
alisphenoid comes from palatoquadrate
what are the parts of the appendicular skeleton?
fins, limbs, girdles
LACKING IN SNAKES, CAECILIANS, CYCLOSTOMES
describe the pectoral girdle in sharks
paired elements
fins articulate with scapula at glenoid surface
what new dermal bones arise in primitive bony fishes?
posttemporal, cleithrum bones, clavicles
posttemporal articulates with skull, clavicles brace together
what results from the posttemporal articulating with the skull?
head is fixed in place
what changes happen in the derived fishes? Pectoral girdles
lose clavicle, cleithrum becomes main brace
gain scapulocoracoid (fused bone)
lose suprascapular (in many groups)
pectoral girdles made of endochondral and dermal bone
what are the tetrapod pectoral girdles made of?
mainly endochondral bone
primitive tetrapods are similar to fish except:
lost posttemporal (head no longer fixed)
gain interclavicle (remains in birds and crocs only)
what is the clavicle and/or coracoid combo in tetrapods?
sternum
NO DIRECT DORSAL BRACING
what do amphibians have for a pectoral girdle
have supra scapular
clavicle lacking in some (salamanders)
describe the pectoral girdle in sauropsids
most lose clavicles, coracoid is main brace
BIRDS ARE THE EXCEPTION
how is a birds pectoral girdle different?
fuses into furculum (WISHBONE)
important for slight muscle attachment (increase surface area)
which mammals retain the basic tetrapod design?
primitive mammals: monotremes ( platypus, echidna) and marsupials (kangaroo)
what is the pectoral structure in placentals?
coracoid is lost in most
the scapula becomes well developed
Clavicle rarely reduced
which placentals do have a reduced clavicle?
some carnivores for increased flexibility and stride length to improve speed
describe the pelvic girdle in fish
made of cartilage or endochondral bone
pair of ischiopubic plates
not connected to vertebrae
what are the 3 plates of the pelvic girdle in tetrapods?
ilium (ILIUM CONNECTS TO VERTEBRAL COLUMN)
ischium
pubis
where do the 3 parts of the pelvic girdle in tetrapods meet?
ventral symphysis
what is a symphysis?
joint of immovable cartilage
why does the tetrapod pelvic girdle have such a weird shape?
allows urogenital and digestive systems to pass through
describe the tetrapod variability in salamanders pelvic
weak
broad pelvic plate
describe the tetrapod variability in frogs/toads pelvic
more developed for jumping
have urostyle for further bracing
describe the tetrapod variability in reptiles pelvic
more robust
triradiate design where the pubis and ischium move apart
describe the tetrapod variability in birds pelvic
pubis and ischium parallel and caudally oriented
fuse with vertebrae to create a synsacrum
pubis bones apart ventrally and do not meet
what do birds pubis bones part ventrally and not meet?
to allow them to lay large eggs
describe the tetrapod variability in mammals (pelvic)
most robust
bones fuse in os coxa to accommodate weight
primitive mammals retain epipubic bone
others have the os coxa fuse to the sacrum for increased strength
what does the epipubic bone do in primitive mammals
supports the pouch of marsupials
what are the modifications to the female pelvis?
wider pelvic canal
wider pelvis overall
pubic symphysis expands for birth
hormone relaxin softens cartilage of pubic symphysis
list the types of fins
paired (pectoral/pelvic)
median (dorsal/anal)
caudal (tail)
what is the function of the paired fins?
steering and braking
what is the function of the median fins?
maintain position and prevent rolling
what is the function of the caudal fin?
thrust
what is the basic structure of a fin?
skin stiffened by rays, either bony dermal rays (bony fish) or long keratin based rays
what are bony dermal rays in fins called?
lepidotrichia
what are long keratin based rays in fins called?
ceratotrichia
what skeletal elements exist in the fins?
both cartilage and bone elements
1 row basal
> or equal to one row radialia
ALL FINS BUT CAUDAL
what are ray fins?
reduced skeleton for improved flexibility
found in actinopterygii
what are fin folds?
broad with 2-3 basals
occur in Chondrichthyes
what are lobed fins?
proximal muscular lobe
central axis (axial) [basal]
2 series of radials
found in sarcopterygii
what are heterocercal caudal fins?
only caudal fins that are strongly asymmetrical
notochord and vertebrae in dorsal lobe
ventral lobe generates upward thrust to counteract negative buoyancy
what groups have heterocercal caudal fins?
sharks because they have no swim bladder
what are diphycercal caudal fins?
symmetrical
notochord and vertebrae very short
what groups have diphycercal caudal fins?
sarcopterygii
what are homocercal caudal fins?
notochord long and dorsal
symmetrical
what groups have homocercal caudal fins?
actinopterygii
Example of tetrapod limb evolution from lobed fishes: forelimbs
Humerus from basal
Radius from preaxial radials
Ulna from post axial radials
Other radials forming digits [or digits are a brand new structure]
Tetrapod forelimbs/hindlimbs structure
Propodium
Epipodium
Autopodium
What is propodium?
Upper arm/thigh
1 large bone
What is the epipodium?
Forearm/shank
2 smaller bones
What is autopodium?
Wrist/ankle to digits
What modifications are made to the forelimb epipodium in different tetrapods?
In bats/frogs/toads ulna is fused and reduced to increase strength (and decrease mass in bats) for specialized locomotion
What modifications are made to the forelimb propodium in tetrapods?
Very little differences, however birds have hollow bones that contain air sacs
And the humerus is extremely robust in moles/digging mammals
What are the differences in the propodium and epipodium of the hindlimbs of tetrapods ?
Propodium: similar across tetrapods
Epipodium: fibula is reduced in birds, and lost or reduced in ungulates, fused to tibia in frogs/toads
Why do ungulates have a lost or reduced fibula?
Increases strength and decreases mass
What is the patella, what animals have it, and how does it form
Knee cap
Only found in birds/mammals
Ossifies in tendon
What is the function of the patella?
Protection from action of tendon, prevents friction
Acts as fulcrum (lifts tendon up to improve leverage and power of quadriceps muscles)
What is the layout of the manus?
Wrist made of 3 rows of carpals
Palm made of metacarpals
Digits called phalanges
What does pentadactyl mean
5 digits (most tetrapods)
How are amphibs manus different
Digit reduction 5–> 4
Reptile and mammal manus variation
Most have 5 digits
Reduced carpals
Reduced digits for locomotion in birds (3)
Why do birds only have 3 toes
For flight
Lots of reduced and fused bones in Manus
What are pes?
Feet
Similar to manus (tarsals/metatarsals/phalanges)
Usually 5 digits (birds and lizards 4)
What is the pes difference in reptiles/birds
Reduced tarsals
Intratarsal joint for flexibility for bipedal locomotion
Lizard that does bipedal locomotion
“Jesus Christ” lizard (basilisk walks on water)
What are the 3 stances for manus/pes
Plantigrade
Digitigrade
Unguligrade
What is plantigrade stance
Slow
Wrist/ankle through digits touch the ground
Ex: elephant human bear
What is digitigrade stance
Fast in bursts
Digits only touching ground
Ex: carnivores/sprinters
What is the advantage of digitigrade stance
Less surface contacting ground which leads to longer strides which increase speed
What is unguligrade stance
Reduced digits (1-4)
Elongated metacarpals/metatarsals
Up on digit tips
Fast and long distance runners
Ex: antelope
Explain why each part of unguligrade stance is important
Less toes: greater strength less mass less friction
Elongated metacarpals/tarsals: increase stride length
Up on digit tips: longest limb and stride
Fast: to outrun carnivores
What is a somatic muscle?
Striated and voluntary
Orient body in environment
Innervated by spinal and cranial nerves
What is visceral muscle?
Muscles of organs and skin
Innervated by autonomic nerves
Smooth and cardiac (involuntary)
What is the origin of a muscle
Attachment that remains stationary during muscle contraction
What is the insertion of a muscle
Attachment that moves during a contraction
What is the belly of a muscle
Body of the muscle
How do muscles usually work
Antagonistically
What are the axial muscles of the somatic muscle group
Trunk and tail muscles
Have strong segmentation, 2 types divided by horizontal septum EXCEPT AGNATHANS
2 types of muscles divided by the horizontal septum
Above: epaxial
Below: hypaxial
Describe the axial muscles in fish
Strong segmentation
Lateral undulation of caudal fin
Interrupted by girdles and gills
Which muscles are dorsal to the gills? Ventral?
Epibranchial
Hypobranchial
Describe the axial muscles in aquatic salamanders
Retain strong segmentation
Use tail/caudal fin for swimming
Describe the axial muscles in amniotes
Lose most segmentation
Increased dorsoventral flexibility
What do the epaxials do in tetrapods?
Straighten vertebral column and lateral flexion
Describe intervertebrals (w/in epaxials)
Deep, retain segmentation
Connect vertebrae between processes
Maintain posture
Describe the Longissimus
Lateral to transverse processes
Dominant extensor in mammals
Assist in head movement
what are the spinales?
medial to transverse processes
assist in head movement
combine with intervertebral to create multifidus spinae that stabilize the vertebral column
what are the iliocostales?
lateral to longissimus
ilium to anterior ribs
allows for lateral undulation
which are the dominant epaxial in reptiles for locomotion?
iliocostales
what are the subvertebrals?
beneath transverse process between axis and pelvis
used to flex vertebral column especially neck and lumbar
give examples of the subvertebrals
quadratus lumborum in amniotes
psoas minor in mammals
what are the obliques
broad sheets of muscle where the fibers fun diagonal from long body axis
in amniotes, this includes the intercostals and supracostal
what is the transverse
transverse abdominis
broad sheets of muscle with perpendicular fibers
what do the obliques and transverse work together to do?
lung ventilation
used during pooping/childbirth
muscular sling for viscera
which muscles are reduced in turtles
obliques and transverse
describe the rectus muscle
rectus abdominis
flexes trunk
sling for viscera
how are the hypobranchials organized in fish
extend from coracoid to lower jaw (coraco- muscles)
to gill arches
what are the coracomuscles in the jaw and the gill arches?
coracoarcual, coracohyoid, coracomandibularis
coracobranchial
what do the hypobranchials do?
open jaw and expand pharynx
what are the modifications to the amphibian hypobranchials?
rectus cervicis comes from coracoarcual, coracohyoid, coracomandibularis, coracobranchials (same function)
geniohyoid, genioglossus, and hyoglossus from coracomandibularis (to operate tongue)
what are the modifications to the amniote hypobranchials?
long straps that allow for a longer neck
rectus cervicis splits into many hyoid and thyroid muscles
(allows for swallowing and moving tongue)
what are the appendicular muscles?
muscles that insert on girdles, fins and limbs
what special hypobranchial muscle do mammals have?
internal tongue muscle called the lingualis
what are the appendicular muscles on fish?
extensors and flexors of paired fins
median fine develop from axial muscles
describe the two muscle categories in tetrapods
extrinsic: arise from axial skeleton, insert on girdle/limb, example is latissimus dorsi
intrinsic: arise on girdle or limb, insert digitally on end
what are the muscle groups?
dorsals
ventrals
describe the dorsals muscle group
most from fish extensors
abduct and extend limbs forward
describe the ventrals muscle group
most from flexors
adduct and flex distal parts backward
list what each of the following intrinsic pectoral dorsals do:
1. Deltoids, scapulohumerus, subscapularis:
2. triceps brace:
3. teres major (mammals):
4. teres minor (mammals):
- rotate or adduct humerus
- extend forearm
- from latissimus dorsi, retract and rotate humerus
- from scapulahumeralis, retract and rotate humerus
list what each of the following intrinsic pectoral ventrals do:
1. coracobranchialis
2. biceps brachii +brachialis
3. spinatus muscles
- adduct forelimb
- flex forearm
- (mammals) from supracoracoideus, protracts and rotates humerus
list what each of the following extrinsic pectoral dorsals do:
1. latissimus dorsi:
2. trapezius:
3. levators, rhomboideus, serrates ventralis:
- largest in mammals, retracts forelimb
- (from cucullaris) splits into multiple pieces in mammals, retracting shoulder
- support and/or retract scapula
list what each of the following extrinsic pectoral ventrals do:
1. pectoralis and supracoracoideus
adducts the forelimb, in mammals pectoralis splits into a few muscles
explain the flight muscles in birds
pectoralis: down stroke, attaches to ventral side humerus
supracoracoideus: up stroke, connects to dorsal side humerus
BOTH originate on sternum and insert on humerus
supracoracoideus tendon allowing it to pull the wing up
list what the extrinsic pelvic muscles do
minimal extrinsic pelvic muscles since the mammal pelvis doesn’t move
caudofemoralis: retracts hindlimb, reduced and different orientation in mammals
list the functions of each of the intrinsic pelvic dorsals do
1. iliocus and psoas major:
2. gluteus, pyriformes, gemelli
3. vastus(s) [3] and rectus femoris, sartorius and adductors [2]
- protract and rotate femur
- adduct and rotate femur
- extend shank and adduct thigh
what muscles make up the quadriceps (quads)
rectus femoris
vastus lateralis
vastus intermedius
vastus medialis
list the functions of the ventral intrinsic pelvic muscles
1. “hamstrings”
2. gracilis
- flex shank
- adduct and retract hindlimb
what are the 3 muscles that make up the hamstrings?
biceps femoris, semitendinosis, semimembranosis
what are the parts of the branchiomeric muscles
mandibular arch
hyoid arch
branchial arches
describe the mandibular arch in jawed fishes
levator palatoquadrati and spiracularis raise upper jaw
adductor mandibulae closes lower jaw
intermandibularis elevates pharynx
describe the mandibular arch in tetrapods
adductor mandibular splits into masseter, temporalis, pterygoideus
intermandibularis splits into mylohyoid and digastric
what do the mylohyoid and digastric do
elevates pharynx for swallowing
opens lower jaw
describe the hyoid arch in jawed fishes
constrictors and interhyoideus
to constrict pharynx
describe the hyoid arch in tetrapods
become depressor mandibulae PART OF DIGASTRIC IN MAMMALS to open lower jaw
sphincter colli elevates throat
explain the hyoid arch in mammals
sphincter colli expands over the head, becoming the platysma and splitting into the facial muscles
what does the platysma do?
functions in nonverbal communication and may have first been for suckling in infants
explain the branchial arches in jawed fishes
constrictors, cucullaris and interarcuals
expand pharynx for gill ventilation and capturing prey
explain the branchial arches in tetrapods/mammals
muscles for swallowing/move larynx and hold mastoid muscles for turning head
what is the order of the digestive tract?
oral cavity, pharynx, esophagus, stomach, small intestine, large intestine
+accessory organs help along the way
what does the oral cavity encompass?
mouth to pharynx
list the parts of the oral cavity
tongue, oral glands, cheek pouches, teeth
describe the tongue in jawed fishes through some amphibians
cyclostome tongues NOT homologous with other vertebrates
primary tongue that lacks muscle and holds prey
describe the tongue in tetrapods
mobile
amphibians: projectile tongue only attached at anterior end to oral cavity, tongue flips out, sticky
what muscles control the tongue in amphibians with a mobile tongue
genioglossus projects tongue, hyoglossus retracts tongue
describe the tongue in birds
variable and very protrusible
woodpecker: longgggg and barbed tongue for reaching into trees to eat larvae
describe the mammal tongue
muscle called frenulum lingo anchors the tongue
functions include grooming, drinking, panting (thermoregulation), communication
what is the function of the oral glands
secretes mucus to lubricate foods for swallowing
list the specialized secretions we talked about
anticoagulants in lamprey
some snakes have venom to subdue prey
what oral glands do mammals have
salivary glands to produce saliva which is a mix of oral secretions (mucus, water, amylase)
what is amylase
enzyme that breaks down starch
describe cheek pouches
*best developed in hamsters
lined with cornified cells (with keratin) to resist abrasion while the pounches act as temporary food storage
what tetrapod groups lack teeth?
turtles, birds
describe the parts of the teeth
crown (exposed part) made of enamel with cusps (bumps) and an inner layer of dentin and pulp cavity with nerves
roots covered with cementum
attach to jaw with collagen fibers
describe the types of tooth attachment to the jaw
acrodont: top attachment (fishes)
pleurodont: side (amphibians/lizards)
thecodont: bony sockets (some fish, crocs, mammals)
which types of tooth attachment are loosely attached
acrodont and pleuredont
list the patterns of tooth development
polyphyodont
diphyodont
what does polyphyodont teeth mean
teeth replaced throughout lifetime, usually in waves (ex: every other tooth), keeps balanced distribution of good teeth across jaw
what does diphyodont teeth mean?
2 sets of teeth in lifetime
milk teeth are the temporary teeth that are adequate for a simple diet and to accommodate a growing jaw, often lacks molars
permanent teeth have a jaw large enough to accommodate molars
what are the different tooth shapes?
homodont
heterodont
what are homodont teeth
all have the same conical shape
occurs in most vertebrates from fish to reptiles
what are the exceptions to homodont teeth
tooth plate: some chondrichtyes have one for crushing mollusks
pharyngeal teeth in some bony fish
what are heterodont teeth
shape varies (just in mammals)
4 types: incisors, canines, premolars, molars
describe incisors
1 cutting edge: important for shipping/cutting food
continuous growth in rodents, rabbits
elephant incisors (tusks) for foraging/fighting
describe canines
spear-like for holding and killing prey, tear flesh
walrus canine: use as ice picks to climb up onto ice, fighting, foraging
describe premolars and molars
premolars: 2 cusps
molars: 3+ cusps, modified for diet
BOTH CHEEK TEETH
what are the types of cheek teeth?
secodont
solenodont
bunodont
what are secodont cheek teeth
laterally compressed and pointed
cusps of upper and lower teeth offset
allows for scissor-like action to cut flesh
what are selenodont cheek teeth
flattened
crescent enamel folds
[herbivores] for grinding vegetation
what are bunodont cheek teeth
generalist teeth
low rounded cusps
found in omnivores human teeth
what is a narwal tusk
unusually large incisor, usually the left one, function unknown
describe the pharynx in tetrapods
glottis opening to trachea
esophagus opening
describe the pharynx in mammals
nasal and oral pharynx
epiglottis (cartilage) that closes trachea when swallowing to prevent aspiration
uvula
what are the functions of the uvula?
sound production
close off nasopharynx when swallowing
gag reflex
describe the gut wall morphology of the digestive tract
- mucosa
- submucosa
- muscularis
- serosa
what is the mucosa of the gut wall
glandular epithelial lining
what is the submucosa of the gut wall
connective tissue with vessels
what is the muscularis of the gut wall
2 layers of smooth muscle, circular and longitudinal muscle
produce contraction to move food thru (peristalsis)
what is the serosa of the gut wall
outer layer of connective tissue
what is the esophagus
muscular tube that moves food to stomach
describe the bird esophagus
expand to crop with keratinized lining for temporary food storage (largest in seed eaters/herbivores)
PIGEONS produce crop milk (cells lining crop slough off to make “milk” high in fat and proteins to feed nestlings
what is the stomach?
muscular chambers with glandular lining
describe the gastric glands and mucus glands
gastric glands produce HCL and pepsinogen (inactive form of pepsin-HCL activates pepsin to break down proteins)
mucus glands produce mucus to mix food and secretions into chyme, low pH
where does the stomach end
pyloric sphincter
which group has no stomach?
agnathans
what does the stomach look like in jawed fishes?
straight to J shape
some ciliated
what does the stomach look like in amphibians
similar to esophagus
straight
highly dispensable
what does the stomach look like in crocs/birds
2 part stomach: proventriculus and gizzard
what kind of stomach is the proventriculus/gizzard
1: glandular
2: muscular with grit [used to break/grind up food] with keratinized lining
what is the gizzard analogous to in mammals?
teeth
describe the variability in bird stomachs
reduced gizzards in frugivores
describe the standard parts of the mammal stomach
funds at top (glandular part)
gastric rugae (folds) to increase surface area and allow expansion
what’s special about ungulate stomachs
4 part ruminant stomachs for digesting low quality vegetation i.e. grass
what are the 4 parts of the ruminant stomach
rumen
reticulum
omasum
abomasum
what is the rumen
large muscular chamber with bacteria and protists for cellulose fermentation
what is the reticulum
area for fermentation
regurgitate “cud” to chew further
what does the omasum do?
absorb water
what does the abomasum do?
“true” stomach
glandular enzymes produced for protein digestion
what does the small intestine look like agnathans–>primative bony fish
short and straight (rudimentary)
increased surface area with spiral valve
what is the small intestine in derived bony fishes?
pyloric seca (blind pouches)
no spiral value
increased surface area for digestion
what are the 3 parts of the tetrapod small intestine
duodenum, jejunum, ileum
what increases SA in the tetrapod SI
villi (lizards–> mammals)
increased coiling in mostw
where does the small intestine end
ileocolic sphincter
which groups lack large intestines
fish
and simple in amphibians
what is the function of the large intestine?
water absorption
describe the amniote large intestine
colon and rectum
ceca (w/microbes to digest cellulose)
what’s special about horse large intestines? rabbits?
horses are hindgut fermenters, they have an enlarged colon with microbes for cellulose fermentation
rabbits eat their poop to further digest it (coprophagy)
how does the length of the large intestine vary?
length of cecum and overall tract differs based on amount of vegetation consumed
what does the liver do?
produce bile that is stored in the gallbladder
what is bile for?
emulsifier to break down lipids
breaks fat into smaller droplets and mixes them up
what does the pancreas do?
produces enzymes that are released into the duodenum
what are the different pancreas structures
diffuse tissue in the mesentery (some bony fishes)
compact structure seen in first bend of the duodenum
