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The Skull and Visceral Skeleton

What is a skull? Morphologists may refer to… ________________ ________________ ________________ We will consider the “skull” as the “skull” minus the jaws, which are derived from the splanchnocranium. The Skull and Visceral Skeleton.

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The Skull and Visceral Skeleton

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  1. What is a skull? Morphologists may refer to… ________________ ________________ ________________ We will consider the “skull” as the “skull” minus the jaws, which are derived from the splanchnocranium The Skull and Visceral Skeleton

  2. Neurocranium(aka enodcranium, chondrocranium, primary braincase): * * The Skull and Visceral Skeleton

  3. The Skull and Visceral Skeleton Neurocranium origins: Mesenchyme from … Cartilages… * * “nose” “ears” and “eyes”

  4. Taxonomic variation of neurocrania: ___________… remain loosely associated, fibrous cover dorsally ________________… highly developed, envelopes brain, NO bone ____________… remains in primitive fish below dermatocranium, BUT teleosts and tetrapods exhibit endochondral ossification The Skull and Visceral Skeleton

  5. Neurocranial ossification centers: ___________, ____________, __________and _____ *Occipital 1-4 bones and one (reptiles, birds and early amphibians) or two (modern amphibians and mammals) occipital _____________ What do these articulate with? The Skull and Visceral Skeleton

  6. Neurocranial ossification centers: *Sphenoid in humans is composite of __________and ______________. Remains as separate bones in some species… ________________ part of this bone The Skull and Visceral Skeleton

  7. Neurocranial ossification centers: *___________has greatest tendencies to remain cartilage in tetrapods. Comprised of ______________and _______________ In humans… * * The Skull and Visceral Skeleton http://www.theodora.com/anatomy/images/image153.gif

  8. Neurocranial ossification centers: *___________ surrounding the membranous labyrinth can fuse with occipitals or squamous (as in humans) to form the temporal bone The Skull and Visceral Skeleton http://embryology.med.unsw.edu.au/wwwhuman/Hum12wk/Hum12wk.htm#12weekHead

  9. ______________ Derived from dermal bone… however, modern tetrapods exhibit mesenchyme migration and subdermal development 4 basic structures… The Skull and Visceral Skeleton 1) 2)3) and 4)

  10. Dermatocranium: ______________ (cartilaginous fishes) is replaced by _________and __________that fuses with other dermatocranialelements ___________(s), _____________ and pterygoids part of primary palate The Skull and Visceral Skeleton

  11. Dermatocranium: _____________… bones that cover and protect the delicate gill structures of bony fish The Skull and Visceral Skeleton

  12. The Skull and Visceral Skeleton Amphibian skulls: Considerably modified from labyrinthodonts, but still ___________ Only ___________have fully ossified skull… Why? ___________ossified Otic capsule exposed dorsally and laterally and in anurans large spaces exist inferiorly too

  13. Non-avian reptile skulls: Stem reptiles similar to … Modern reptiles still have some ancestral characteristics, namely well ossified neurocraniumand… ______________ (sphenodon and many saurians) Why? The Skull and Visceral Skeleton

  14. “Apsidity”: Stem reptiles lacked temporal fossae (_________________) Ancestors to mammals have a single fossae (__________ skulls) Modern reptiles have two fossae (_____________ skull) Extinct dinosaurs have single superior fossae (_________skull) that may be convergent evolution The Skull and Visceral Skeleton

  15. _______________: Development of secondary palate makes … The Skull and Visceral Skeleton

  16. Cranial kinesis: Movement of various functional parts of the skull independent of other parts is _________________ Teleost, squamates and birds well adept at this… for example fish can move… The Skull and Visceral Skeleton Why?

  17. Birds: Modified reptile skull in 2 functional regions…1) 2) Light weight dermal bones and bigger space for large brain The Skull and Visceral Skeleton

  18. Mammals: Key features are ____________ (mandible), __________ ________ _________ and ____________ The Skull and Visceral Skeleton

  19. The Skull and Visceral Skeleton

  20. Visceral skull: Derived from … Origins are _______________ __________________ behind the palatoquadrate (jaw) is homologous to the __________in mammals. The Skull and Visceral Skeleton

  21. _______________becomes one of the 3 ossicles in mammals… The Skull and Visceral Skeleton

  22. _______________becomes one of the 3 ossicles in mammals… The __________ (or stapes) is present in basal groups. The Skull and Visceral Skeleton

  23. Other pharyngeal arches become portions of: 1) 2) 3) 4) The Skull and Visceral Skeleton

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