general skull and post cranial Flashcards
cartilage
chondrocytes in lacunae within matrix of proteoglycans, protein fivers (collagen and elastin) and inorganic salts
no blood vessels or nerves
bone
osteocytes within lacunae in matrix of inorganic salts and protein (mainly collagen)
bone has blood vessels and nerves inside
cells in cartilage
chondrocytes
cells in bone
osteocytes
trebecular bone
composed of bony struts called trebeculae, appears spongy
compact bone
does not look porous with naked eye though there are many canals within
ossification
the process by which bone is formed
endochondral bone
cartilage forms first, then is ossified into bone
intramembranous bone
no cartilagenous stage - intermembranous ossification of mesenchymal cells
dermal bones
intramembranous bone formed by ossification of mesenchymal cells in the dermis of the skin
components of the skull N/A
chondocranium, splanchnocranium, dermatocranium
chondocranium N/A
splanchnocranium N/A
dermatocranium N/A
components of the axial skeleton
notochord, vertebral column, ribs, sternum
notochord
HOLLOW IN - elasmobranchii and actinopterygii for notochord to pass, pads in between
TETRAPODS - capped with intervertebral bodies made of cartilage and fibrous connective tissue
MAMMALS capped with intervertebral disks with remnants of the notochord
vertebral column
ribs
COMPOSED OF cartilage and endochondral bone from sclerotome epimere mesoderm
NO RIBS in agnatha and holocephali
GREATLY REDUCED in elasmobranchi
YES RIBS - all others
sternum
components of the appendicular skeleton
girdles (pelvic and pectoral), and paired fins or limbs
YES in extant gnathostomes unless secondarily lost
NO in agnathans
in chondrichthyes, actinopterygii, sarcopterygii includes paired fins and their girdles
paired fins/limbs
pelvic girdle
pectoral girdle
emb. origin of notochord
mesoderm
emb origin of ribs
sclerotome epimere mesoderm
emb origin of the sternum
mesenchymal cells of the somatic hypomere mesoderm
somatic hypomere mesoderm is located
outside ofthe coelum
sclerotome epimere mesoderm is located where in embryo
in somites, so to sides of the nerual tube/notochord
cartilage and endochondral components of the appendicular skeleton are from
somatic hypomere mesoderm
3 main functions of the skeletal system
- protects delicate tissues
- provides an attachment point for muscles, acting as levers
- provides structural support, supporting body weight or shape
parts of vertebrae
transverse processes, neural spine, neural arch, pre and post zygapophyses, centrum, hemal arch, hemal spine
*** not all in all vertebrae or all taxa!!
neural spine
neural arch
hemal spine
hemal arch
transverse processes
post-cranial axial skeleton in agnatha (jawless vertebrates)
inc. myxinoidea and petromyzontida (hagfish and lamprays)
large notochord providing structural support
MYXINOIDEA - secondary loss of vertebrae
PETROMYZONTIDA - cartilagenous vertebrae with small neural arches on the dorsal surface of the notochord
post - cranial axial skeleton in chondrichthyes
inc. holocephali and elasmobranchii (dogfish and sharks)
cartilagenous vertebrae
HOLOCEPHALI - no centra, notochord for axial structural support with neural arches and hemal arches resting on notochord
ELASMOBRANCHII - YES centrum on each vertebrae! notochord through middle of centrum, in all spinal chord through neural arch in all, and dorsal aorta through hemal arch and spine in caudal vertebra
- TRUNK AND CAUDAL VERTEBRAE
post - cranial axial skeleton in actinopterygii
ray finned fish
ossified endochondral bone from somatic hypomere mesoderm
centra providing major structural body support, with notochord through middle.
very tall and pointy neural spine and noral arch with spinal cord through
ribs attached
post cranial axial skeleton in sarcopterygii
fleshy finned fish
ossified endochondral bone from somatic hypomere mesoderm
centra reduce or secondarily lost, with neural arches and hemal arches resting on the notochord
post cranial axial skeleton in tetrapods
solid centra WITHOUT notochord!
ossified endochondral bone from somatic hypomere mesoderm
centrum with neural spine and neural arch with spinal chord going through
to the sides, transverse processes and diapophyses and parapophyses, articulate with the ribs
diapophyses
parapophyses
in mammals, what do intervertebral discs contain
remnants of the notochord
regionalization of the vertebral column in elasmobranchii, actinopterygii, sarcopterygii
TRUNK and CAUDAL
caudal vs trunk region in elasmo, actin, sarcopt
CAUDAL - hemal arch and spine with dorsal aorta though
more pointy neural spine
TRUNK - NO hemal arch and spine, instead articulate with ribs, and less pointy neural spine
attachment of the pectoral girdle in actinopterygii, sarcopterygii, chondrichthyes
actinopt and sarcopt - ATT TO DORSAL POSTERIOR REGION OF THE SKULL
chondrich - embedded in muscle walls
attachment of the pelvic girdle in chondrich, actinopterygii, sarcoterygii
USUALLY embedded in the muscles of the body wall
paired fins in chondrichthyes
proximal regions supported by thick skeletal elements (pterygiophores)
*** basal pterygiophores long out along fins, radial pterygiophores along base of fin rays
distal regions supported by fin rays made of keratin
provide stability by preventing pitch roll and yaw AND help with steering
AND in male and intersex claspers of pelvic fins are intromittent organs, sperm transfer
paired fins in actinopterygii
RAY FINS - thin skin and connective tissue supported by fin rays of bone or cartilage
stabilization, steering, keeping place in water and stopping, propulsion
paired fins in sarcopterygii
FLESHY FINS - series of bones that articulate with mobile joints, supportive muscles extend into the fins
distal ends generally still have fin rays supported by skin and connective tissue
swimming, pivoting, maneuvering through vegetation, walking on bottom surface, holding position
major role of skeleton that differs in terrestrial vs aquatic
support of body weight
structural differences between terrestrial vertebrates (most tetrapods) and ancestors
- GIRDLES - larger, more ossified to withstand compressive forces of body weight
- FIN RAYS - replaced with digits, more sturdy, flexible, good for grip and balance
- PEC GIRDLE no longer attached to skull, and differentiation of cervical region of the vertebral column. good for headmobility, freedom of movement for appendages
- PELVIC GIRDLE fused to sacral region of the vertebral column - reinforces and strengthens both structures, and propulsion by hind limbs efficiently transferred
home many cervical vertebrae to amphibians
only one (versus two or more in amniotes)
regions of the vertebral column in tetrapods
cervical
trunk (differentiated into thoracic then lumbar in some)
sacral
caudal
differentiating parts of the vertebral column in tetrapods
sacral vertebrae fused together to form sacrum in some
trunk bears ribs
thoracic bears ribs, lumbar does not
vertebral column adaptations in birds
in aves, sacral lumbar, several thoracic and caudal fuse into SYNSACRUM which fuses with pelvic girdle
strong and stable for flight, light in weight bc less connective tissue but still strength
regionalization of the cervical vertibrae
in TETRAPODS:
1st - ATLAS - no centrum, just neural canal, transverse foramen (little holes in processes on sides) ALLOWS NODS
2nd - AXIS - ODONTOID PROCESS to articulate with atlas (inserted into the neural canal) and allows the head to turn side to side **ONLY IN AMNIOTES
in many amniotes (NOT AMPHIBIA), additional vertebrae
what cervical vertibrae adaptations to amniotes have
2nd vertebrae is AXIS, and may have many additional cervical vertebrae for neck mobility
differences in tetrapod limb posture - what, and which taxa generally have
SPRAWLED - amphibia, testudinata, lepidosauria
ERECT - mammalia and aves
differences in limb movement between sprawled and erect
sprawled - recovery stroke needs overarm swing so more energy and slower, more energy into recovery
erect, pendulum like swing in one direction so easier, less energy, more energy into propulsion
differences in pectoral girdle for different limb postures
sprawled - more medially directed compressive forces so enlargement of ventral elements of the pectoral girdle
erect - more ventral forces so enlargements of dorsal elements of the pectoral girdle
three types of foot postures
PLANTIGRADE - fully planted
DIGITIGRADE - partially planted
UNGULIGRADE - only tips of phalanges planted
how do differences in foot posture affect speed and efficiency, whos faster?
who withstands shock better
FASTER - UNGULIGRADE bc of contribution of foot bones to length of leg therefore greater stride length
LESS SHOCK - plantigrade because greater surface area in contact with the ground
pre/post zygapophyses - who and what?
TETRAPODS
help prevent twisting of the vertebral column
PRE is on anterior of the vertebrae, two projections that support the POST of the posterior vertebrae
PRE SUPPORTS POST
_____ supports _____?? (zygapophyses)
pre supports post!!
sternum - who has and who doesn’t??? composed of??
NO - agnatha, chondrichthyes, actinopterygii, sarcopterygii
YES - most tetrapods BUT evolved independantly in several diff. taxa
composed of cartilage and/or endochondral bone
sternum adaptation for aves
large KEEL for attachment of flight muscles
ribs - amphibians vs amniotes
amphibians - no articulation with sternum
amniotes - composed of COSTAL (vertebral) which articulates with the thoracic vertebrae and STERNAL (sternum) which articulate with the sternum to form rib cage
