Post Cranial Skeleton Flashcards
post-cranial skeleton includes
axial and appendicular skeleton
appendicular skeleton includes
paired fins/limbs and girdles
axial skeleton includes
notochord, vertebral column, sternum, ribs
axial skeleton developmental origins
Notochord from mesoderm
Vertebrae and ribs - sclerotome epimere mesoderm (most medial part of the somites)
sternum - mesenchymal cells of somatic hypomere mesoderm
appendicular skeleton developmental origins
somatic hypomere mesoderm
possible components of a vertebrae
centrum, neural arch, neural spine, hemal arch, hemal spine, prezygapophyses, postzygapophyses, diapophyses, transverse processes
notochord function
in dev, proteins that signal ectoderm to differentiate into neural plate ectoderm
BUT
attachment point for axial muscles to pull, bending the tail back and forth and producing LATERAL UNDULATIONS that propel the body forward
MYXINOIDEA axial
secondary loss of vertebrae
NO RIBS
PETROMYZONTIDA axial
cartilaginous
NO RIBS
small neural arches on dorsal surface of notochord
ACTINOPTERYGII axial
ossified
very pointy!
hollow centrum with notochord passing through, thickens to firm a pad between
TRUNK - centrum, neural arch and pointy neural spine (spinal chord passing through neural arch, extra hole with ligament passing through), 2 ribs attached either side of each centrum (dorsal and ventral)
CAUDAL - centrum, neural arch and spine, hemal arch and spine
NO zygapophyses
NO sternum
SARCOPTERYGII axial
ossified
no OR reduced centrum
TRUNK - neural arches and hemal arches on notochord, fused ribs
CAUDAL - neural and hemal arches on notochord
NO zygapophyses
NO sternum
AMPHIBIA axial
mostly solid centra, some hollow
in most, intervertebral bodies between
YES zygapophyses
YES sternum
CERVICAL - only 1, atlas! transverse foramen
TRUNK
SACRAL
CAUDAL
MAMMALIA axial
solid centrum capped by intervertebral discs
***intervertebral discs have gel centres from the notochord
YES zygapophyses
YES sternum
CERVICAL atlas + axis plus more!! transverse foramen
THORACIC - costal rib articulating w/ vert and sternal rib articulating with the sternum
LUMBAR
SACRAL
CAUDAL
CROCODILIA axial
solid centrum capped by intervertebral bodies
YES zygapophyses
YES sternum
CERVICAL atlas + axis, transverse foramen
THORACIC - costal rib articulating w/ vert and sternal rib articulating with the sternum
LUMBAR
SACRAL
CAUDAL
AVES axial
solid centrum capped by intervertebral bodies
YES zygapophyses
sternum with large KEEL on ventral side for attachment of flight muscles
CERVICAL atlas + axis, transverse foramen
THORACIC several in synsacrum, costal rib articulating w/ vert and sternal rib articulating with the sternum
LUMBAR, SACRAL - fused into SYNSACRUM, fused to pelvic girdle
CAUDAL several in synsacrum
TESTUDINATA axial
solid centrum capped by intervertebral bodies
YES zygapophyses
YES sternum
CERVICAL atlas + axis, transverse foramen
THORACIC - costal rib articulating w/ vert and sternal rib articulating with the sternum
LUMBAR
SACRAL
CAUDAL
LEPIDOSAURIA axial
solid centrum capped by intervertebral bodies
YES zygapophyses
YES sternum
CERVICAL atlas + axis, transverse foramen
THORACIC - costal rib articulating w/ vert and sternal rib articulating with the sternum
LUMBAR
SACRAL
CAUDAL
ELASMOBRANCHI axial
cartilaginous
NO zygapop
No sternum
all centrum hollow, notochord passing through, thickening to form pad between
TRUNK - centrum, neural arch and spine, ribs ATTACHED????? and greatly reduced
CAUDAL - centrum, neural arch and spine, hemal arch and spine (dorsal aorta passing through hemal)
** spinal chord passing through neural arch
HOLOCEPHALI axial
cartilaginous
NO zygapop
NO sternum
no centrum, no ribs, yes neural and hemal arches sitting on large notochord
petromyzontida appendicular
NONE!!!
myxinoidea appendicular
NONE!!!
elasmobranchii appendicular
pectoral girdle embedded in muscle wall
pelvic girdle embedded in muscle wall
proximal regions of fins supported by pterygiophores (thick sturdy skeletal elements), distal regions supported by fin rays (keratin)
holocephali appendicular
pectoral girdle embedded in muscle wall
pelvic girdle embedded in muscle wall
proximal regions of fins supported by pterygiophores, distal by fin rays (keratin)
actinopterygii appendicular
pectoral fused to the skull
pectoral girdle embedded muscles of body wall
RAY FINS (bone or cartilage) supporting a thin layer of skin/connective tissue
sarcopterygii appendicular
pectoral girdle fused to the skull
pelvic girdle embedded in body wall
FLESHY FINS - series of bones w/ MOBILE JOINTS, muscles to move those extending into the fin
fin rays on distal ends supporting thin layer of skin and connective tissue
amphibia appendicular
pectoral girdle NOT fused to skull, axial skeleton suspended from pectoral girdle by muscle
pelvic girdle fused to sacral vertebrae
testudinata appendicular
pectoral girdle NOT fused to skull, axial skeleton suspended from pectoral girdle by muscle
pelvic girdle fused to sacral vertebrae
lepidosauria appendicular
pectoral girdle NOT fused to skull, axial skeleton suspended from pectoral girdle by muscle
pelvic girdle fused to sacral vertebrae
crocodilia appendicular
pectoral girdle NOT fused to skull, axial skeleton suspended from pectoral girdle by muscle
pelvic girdle fused to sacral vertebrae
aves appendicular
pectoral girdle NOT fused to skull, axial skeleton suspended from pectoral girdle by muscle
pelvic girdle fused to sacral vertebrae
mammalia appendicular
pectoral girdle NOT fused to skull, axial skeleton suspended from pectoral girdle by muscle
pelvic girdle fused to sacral vertebrae
girdle function
attachment site for muscles
stabilizes appendages by bracing against the body
function of paired fins in chondrichthyes
STABILITY to prevent roll, pitch and yaw
STEERING to control direction while swimming
in male and intersex - CLASPERS of pelvic fins intromittent organs, internal fertilization
** NOT ** PROPULSION*
function of paired fins in actinopterygii
STABLITY prevent roll pitch and yaw
STEERING
maintaining body position/stopping
PROPULSION YES (precise but slow)
function of fleshy fins in sarcopterygii
PRECISE SWIMMING/PROPULSION!!!!
can even be used for waling along bottom surfaces
support of weight in aquatic vertebrates
doesn’t have to do!!! body supported by water
support of weight /locomotion - sprawled
WEIGHT: often rest ventral body surface on ground so vert column doesn’t need to bridge weight
LOCO: recovery - overarm swing requiring anterior/posterior and dorsal/ventral movement HIGH ENERGY EXPENSE
FORCE: medially directed forces therefore ventral element enlarged to withstand compressive forces
support of weight/locomotion - erect
WEIGHT: pillars of support while stationary and moving
in quadrapedal, bridge to spread weight to 4 legs
vert. column stabilized by epaxial muscles
LOCO: recovery stroke - pendulum like swing, only anterior/posterior movement so less energy expended here and more for propulsive stroke
FORCE: vertically therefore enlarged dorsal elements of pectoral girdle ex. scapula
support of weight - MODIFICATIONS for terrestrial vertebrates
larger and more ossified girdles to withstand the compressive forces of body eight
fin rays - digits: sturdy, flexible, mobility to adjust to variable terrain, grip, balance
pectoral girdle lost attachment to skull, cervical region of vertebral column differentiated
pelvic girdle fused to sacral region of the vertebral column
general regionalization of the vertebral column
FISH - only trunk and caudal
AMPHIBIANS - cervical, trunk, sacral, caudal
AMNIOTES - cervical, thoracic, lumbar, sacral, caudal
ATLAS
no centrum
articulates w/ occipital bones of skull
nods!
AXIS
ODONTOID PROCESS - anterior projection that inserts into the neural canal of the atlas, turning head side to side
Propulsive v recovery stroke
propulsive - foot contacts ground, limb moves from anterior to posterior
recovery, no contact, posterior to anterior
3 types of foot posture + pros/cons
- PLANTIGRADE - tarsals, metatarsals, phalanges/ carpals, metacarpals, phalanges all in contact w/ ground
Shorter stride and heavy foot BUT less shock from impact with ground
- DIGITIGRADE - just phalanges in foot
- UNGULIGRADE - very few OR no phalanges in contact
light foot and long stride so very fast, but lots of shock with impact
who has zygapophyses?
only tetrapods
who has a sternum?
only tetrapods (convergent)
