Midterm 2 Flashcards
What are the 3 parts of the vertebrate skull?
chondrocranium, splanchonacrium, and dermatocranium
what is the chondrocranium?
the braincase - endochondral ossification
what is the splanchnocranium?
gill arches and core parts of the upper and lower jaws - endochondral ossification
what is the dermatocranium?
exterior covering of the skull and lower jaw - intramembranous ossification
define endochondral ossification
hyaline cartilage is replaced by bony tissue
define intramembranous ossificiation
bones develop from mesenchymal connective tissue
where does the chondrocranium develop from?
neural crest and mesenchyme - becomes bone and cartilage in adults
what are nasal, optic, and optic capsules associated with?
nose, eyes, and ears
early chondrocranial dev: what are the 3 bars of cartilage in embryo?
trabeculae, parachordals, and occipitals
late chondrocranial dev: what do the bars of cartilage fuse into?
ethmoid plate, basal plate, and occipital arch
what is unique about osteichthyan cartilage fusion?
they ossify to produce the bones of the braincase
where does splanchnocranium develop from?
neural crest cells
what are the parts of the splanchnocranium?
1st: mandibular arch = palatoquadrate cartilage and meckels cartilage
2nd: hyoid arch = hyomandibula and ceratohyal
splanchnocranium: what are the 5 branchial arches?
- support gills in fish
- pharyngobrnachial, epibranchial, ceratobranchial, hypobranchial, and basibranchial
what are the hypothesis of jaw evolution?
1st arch became the mandibular arch and the 2nd became the hyoid BUT there is evidence that jaws didn’t come from pre-existing arches, rather from other mouth tissues
explain autostyly jaw suspension
- palatoquadrate is fused in skull and attached to mandible
- hyoid arch has no role in suspending the jaws
- primitve condition, retained by ratfish, lungfish, and tetrapods
explain amphistyly jaw suspension?
jaws attached to skull via hyomandibula posteriorly and ligament anteriorly
explain hyostyly jaw suspension?
jaws attached to skull via hyomandibula
what are the origin of middle ear bones in tetrapods?
- ossification in palatoquadrate and meckels cartilage
- hyomandibula reduced to stapes, which is adapted for hearing in frogs and reptiles
what is the origin of mammal middle ear bones?
- quadrate and articular transformed into middle ear bones (incus and malleus)
- angular forms ectotympanic part of temporal bone
where does the dermatocranium develop from
from mesenchyme
what does the dermatocranium cover?
braincase and splanchnocranium forms roof, side walls, and palate of the skull - to provide protection and muscle attachment sites
what are the 6 series within the dermatocranium
facial, orbital, temporal, vault, palatal, and mandibular
what is special about dermatocranium evolution?
elements slowly fused into each other for more strength and complexity
how would you describe cyclostome chondrocranium and splanchnocranium?
rudimentary and cartilaginous
how would you describe the skull of ostracoderms?
plates of dermal bone
what kind of jaw do placoderms and acanthodians have?
autostyly - upper jaw is bound to skull
explain the chondrichthyan skull
carilaginous chondrocranium and splanchnocranium
what jaw do chondrichthyans have?
amphistyly
explain osteichthyan skull
dermal bones sheathes chondrocraniu, and splanchnocranium
- dermal bones connect skull to shoulder girdle
explain the skull of early tetrapods
reduction of dermal skull bones: opercular lost, pectoral girdle detaches from skull
explain lissamphibian skull
dermal bones fusion and reduction
explain amniote skull
skull fenestration, reduction of dermal bone
define cranial kinesis in actinopterygians
jaw movements that can change the size and shape of mouth = when mouth expands, suction feeding occurs
explain cranial kinesis in sarcopterygians
braincase ossifies so the snout can lifted
which groups lost cranial kinesis?
dipnoans, crocodilians, tetrapods, and turtles
explain cranial kinesis in reptiles
lizards and snakes have the ability to rotate their snout, palate, and quadrate
define external nares
nasal openings outside of skull
- osteichthyan, osteolepiforms, tetrapods
define internal nares
nasal openings on the roof of the mouth
- osteolepiforms, tetrapodsde
define primary palate
dermal bones anteriroly to the internal nares
define secondary palate
anteriorly hard bony plate and posteriorly soft palate to strengthen skull and separate mouth from nasal passage
what parts encompass the axial skeleton
vertebral column, ribs, gastralia, and skeletal elements that support median fins
vertebrae embryology: what happens to the epimere?
segmentally arranged into somites on each side of the skeleton
vertebrae embryology: what are the 3 mesodermal populations of the somite?
dermatome, mytome, and sclerotome
vertebrae embryology: what does the dermatome develop into?
dermis
vertebrae embryology: what does the myotome develop into?
musculature
vertebrae embryology: what does the sclerotome develop into?
vertebrae and ribs, settles along the notochord
vertebrae embryology: in teleosts, what is involved in intramembranous bone formation?
notochordal sheath
define resegmentation
cells from neighboring sclerotomes fuse as they move into position forming “secondary sclerotomes”
what do sclerotomes develop into around the notochord
perichordal tube
what is the notochord?
long continuous rod that is a hydrostatic organ - develops into nervous system
what is the function of the vertebrae?
protect spinal cord and muscle attachment
what supports the spinal chord?
neural canal
what are the 4 vertebral elements?
haemal arch and spine (tail), intercentrum, neural arch and spine, and pleurocentrum
centra: define siplospondyly
2 centra per segment: pleurocentrum and intercentrum - osteolepiforms, labyrinthodonts
centra: define monospondyly
1 centrum per segment - elasmobranchs, lissamphibians
what happens to the centra of the lepospondyly?
intercentrum
what centra do lissamphibians have?
pleurocentrum, instead of intercentrum
what happens to amniote centra?
pleurocentra dominate and intercentra is reduced
centra shape: describe amphicoelous
both surfaces are concave
centra shape: describe opishtocoelous
anterior is convex, while posterior is concave
centra shape: describe procoelous
anterior concave, posterior convex
centra shape: acoelous
both surfaces are flat
centra shape: heterocoelous
both surfaces are saddle shaped
what are the vertebral protrusions of tetrapods?
diapophysis
what are the vertebral protrusions of fishes ?
basopophyses
what protrusion contact heads of rib?
diapophysis and parapophysis
what protrusion contact ventral rib?
basopophysis
what protrusion connects neural arches?
zygapophysis
what are the zonations of the vertebral column?
trunk and caudal (tail), caudal, dorsal, sacral (pelvis), and cervical (neck)
what are the 2 heads of ribs and their functions?
tuberculum: contacts diapophysis
what are the components of actinopterygian ribs?
1 set of actual ribs and 1-3 sets of intermuscular bones
what are the components of tetrapod rib?
vertebral, intermediate, and sternal - plesiomorphic
what is unique about bird ribs?
cervical reduced, uncinate process on the cervical and dorsal ribs, sternal ossified, many sacral, caudal lost
what is unique about mammal ribs?
cervical, lumbar, and caudal are lost and thoracic region is defined
define gastralia and name its function
ventral dermal bones that provide protection and muscle attachment sites
what are fish tail shapes?
heterocercal, hypocercal, diphycercal, and homocercal
what are the components of the appendicular skeleton?
paired appendages on girdles: pectoral and pelvic
define striated muscle
external muscles of limbs, trunk, and jaws, made up of multinucleate cells, biggest cells in the body
what is red meat made out of and what is its function?
rich in myoglobin and for endurance
what is white meat made out of and what is its function?
poor in myoglobin and for rapid contraction
define smooth muscle
mononucleate cells, slow action, forms sheets arounf organs and blood vessels
define cardiac muscle
heart muscle, striated, mononucleate cells joined by discs
what does the mesenchyme develop into?
smooth muscle and viscera
what does the sphlanchnic layer of hypomere develop into?
smooth muscle of digestive tract and cardiac muscle
what does the somatic layer of the hypomere develop into?
skeletal muscles of limbs
what does the somitomeres develop into?
skeletal muscle of head and branchial arches
what does the myotomes of somites develop into?
skeletal muscle
what is the organization of the skeletal muscle?
muscles > fascicles > muscles cells (fibres) > myofibrils
collagenous sheaths: what surrounds muscles?
epimysium
collagenous sheaths: what surrounds fascicles?
perimysium
collagenous sheaths: what surrounds cells?
enodmysium
what casues contraction in sarcomeres?
sliding of the filaments (actin and myosin)
what creates the striated appearance in sarcomeres?
alteration between myosin-bearing and myosin-free parts
what are tendons?
connective tissue (collagen)
what does it mean if a muscle is in its active state?
force is produced, muscles contract, and high load causes muscle to stretch
