Lab 4 - Comparison of Cranial Skeleton Flashcards
What is the function of the skeleton?
For locomotion and support for the animal
What are the two basic parts of the skeleton?
The dermal skeleton and endoskeleton
What kinds of structures are the dermal skeleton?
Outer skull bones, teeth, and structures like a turtle shell
What does the endoskeleton consist of?
It can be divided into visceral and somatic components
What structures make up the visceral skeleton?
The gill arches, jaw components, and support of the pharynx.
What makes up the somatic skeleton?
Axial and Appendicular skeleton subdivisions.
What structures make up the axial skeleton?
The vertebrae, ribs, and sternum
What structures make up the appendicular skeleton?
The paired appendages and the girdles that support them.
What is the cranial skeleton composed of?
It consists of both the dermal skeleton and endoskeleton.
What is special about the Chondrichthyes skull?
It is entirely cartilaginous and has a movable upper jaw.
What is the palatoquadrate cartilage?
It forms the upper jaw in sharks
What is the rostrum?
It houses the nares and ampullae of lorenzini
What is Meckel’s (or mandibular) cartilage?
It forms the lower jaw in sharks
How does an Osteichthyes skull differ from a dogfish skull?
The skull isn’t cartilaginous, its upper jaw is fused to the rest of the skull, and there are opercular bones.
What is the maxilla?
The upper jaw
What is the mandible?
The lower jaw
What are the quadrate and articular bones important for in non-mammals?
They function as the hinge point for the jaw (quadrate=above, articular=lower)
What is the dentary bone?
Makes up the majority of the lower jaw in most vertebrates
What is the palatine?
It is the bone at the roof of the mouth. It is important for creating a barrier between the nasal passage and mouth
What is the choana?
There are two (one for each of the nares) that open into the nasopharynx
What is the temporal fenestrae?
“Holes” near the top of the skull where muscles attach on one side for the jaw.
What is special about the rattlesnake skull?
It has a highly modified quadrate bone, where it is attached to an extra hinge, allowed for a greater range of motion. Also, it is elongated and they can move their upper jaw to an extent
What is the difference between aves skulls and reptile?
Aves skulls have more spongy bone and fusion of bones and have more holes, so they are lighter. Also, The orbit is massive in the aves, which is important because they have good sight. Also, no teeth.
When did the palatine bone evolve?
The amphibians have a greatly reduced one, but it is quite prominent in reptilia first.
