Post-Cranial Skeleton Flashcards
post cranial skeleton (2)
- axial skeleton
- appendicular skeleton
axial skeleton (4)
- vertebral column
- notochord
- ribs
- sternum
appendicular skeleton (2)
- paired fins or limbs
- girdles
neural arch
- protects spinal cord
hemal arch
- protects blood vessels/dorsal aorta
processes
- spine, zygapophyses, diapophyses
- provide sites for muscle attachment or specialized regions for articulation with other skeleton elements
agnatha vertebral column (3)
- large and prominent notochord
- hagfish do not have vertebrae
- petromyzontida have cartilaginous vertebra consisting of small neural arches on the dorsal surface of the notochord; no centra or hemal arches
chondrichthyes vertebral column (3)
- cartilaginous vertebral column
- each vertebra has a centrum
- centra provide major axial structural support for body and surround the notochord
actinopterygii vertebral column (3)
- ossified endochondral bone
- centra provide major axial support for the body and surround the notochord
- large neural spines and ribs provide sites for muscle attachment
sarcopterygii vertebral column (2)
- ANCESTRAL: ossified (endochondral bone) and had centra surrounding notochord
- EXTANT: centra reduced or secondarily lost; neural and hemal arches rest on large and prominent notochord
tetrapoda vertebral column (2)
- solid centra that does not surround the notochord
- composed of ossified (endochondral bone) and provides axial structural support for the body
notochord presence in: (2)
- chondrichthyes
- hollow centra that notochord passes through
- notochord thickens to provide a pad between each vertebrae
notochord presence in: (2)
- actinopterygii
- hollow centra that notochord passes through
- notochord thickens to provide a pad between each vertebrae
notochord presence in: (2)
- tetrapods
- articular ends of centra capped with intervertebral bodies/pads
- intervertebral bodies composed of cartilage/fibrous connective tissue
notochord presence in: (2)
- mammals
- articular ends of centra capped with pads called intervertebral disks
- composed of cartilage, fibrous connective tissue, and notochord remnants
what is the purpose of intervertebral disks
- cushion between vertebrae to assist in shock absorption
which taxa has a regionalized vertebral column
- gnathostomes
vertebral column regionalization: chondrichthyes
- two regions: trunk and caudal
vertebral column regionalization: actinopterygii
- two regions: trunk and caudal
vertebral column regionalization: sarcopterygii
- two regions: trunk and caudal
how do trunk and caudal vertebrae differ? (2)
- trunk: rib attachment sites, only have neural arch/spine
- caudal: hemal arch/spine and neural arch/spine
notochord/vertebral column main function
- lateral undulations
lateral undulations (2)
- alternating contractions of muscles on each side of body produce that provide propulsive force to push the body froward
- notochord/vertebral column serve as a firm, but flexible rod that axial muscles pull from side to side to bend body, moving tail back and forth
which taxa use notochord to produce lateral undulations (3)
- sarcopterygii
- petromyzontida
- myxinoidea
which taxa use the vertebral column to produce lateral undulations (3)
- actinopterygii
- tetrapoda
- chondrichthyes
appendicular skeleton: agnathans
- do not have appendicular skeleton