chapter 7-skull Flashcards
4 functions of the skeleton
give body shape
support body support
work with muscles for movement
protect soft parts
two large “divisions” of the skeleton
exoskeleton and endoskeleton
the real two divisions of the skeleton
cranial skeleton
postcranial skeleton
the three parts of the cranial skeleton
splanchnocranium
chondrocranium
dermatocranium
the most ancient part of the skeleton skull, supports the pharynx
splanchnocranium
what cells derive the splachnocranium
neural crest cells
underlies the brain, can be made of cartilage in some species, in others it has become bone
chondrocranium
outer skull casing
what we really think of when we think skull
dermatocranium
skull components surrounding/encasing the brain
can be 1,2,or all 3 parts
braincase
braincase and attached sensory capsules
neurocranium
how is the chondrocranium seen in elasmobranchs
makes up the majority of the braincase and remains as cartilage
how is the chondrocranium seen in other vertebrates
embryonic scaffold for parts of the neurocranium
meaning it becomes bone
4 things the splanchnocranium does
supports gills
supports buccal pump muscles
contributes to jaw
contributes to hyoid arch
what is believed to be the precursor for the splanchnocranium
protochordate pharyngeal bars
when organisms evolve to leave water where does the splanchnocranium go
middle ear, larynx, rings of trachea