Chapter 7 Part 2: Cranial Skeleton Flashcards
How many middle ear bones are found in mammals?
3!
From what bones of the splanchnocranium are the middle ear bones derived?
Incus, stapes, and malleus
Incus evolved from quadrate; Malleus evolved from articular
How does the 3 middle ear bones compare to the other tetrapod vertebrates?
Birds only have 1 of those for ear (columella)
Be able to name some tetrapod derivatives of the First branchial arch
becomes upper and lower jaws
Be able to name some tetrapod derivatives of the Second branchial arch
leads to parts of the hyoid apparatus
Be able to name some tetrapod derivatives of the 3rd and 4th BRanchial arches
formation of larynx and various cartilages in throat region(breathing and vocalization)
Dermatocranium
Superficial to chondrocranium – derived from membrane bone
Roof and lateral walls of the skull
Upper and lower jaws
Palate
Operculum(in bony fish)
Structures in Facial
premaxilla, maxilla, nasal
Structures in Orbital
lacrimal, prefrontal, postfrontal, postorbital, jugalS
Structures in Vault
frontal, parietal, postparietal
Structures in temporal
Quadratojugal, Intertemporal, Supratemporal, Temporal, Squamosal
Palatal: What is a secondary palate and which vertebrates have one?
o Vomer
o Palatine
o Ectopterygoid
o Pterygoid
o Parasphenoid
Seen in mammals, air flows in more than one cavity (oronasalcavity only has single cavity for air flow)
Lower jaw structures
o Lateral: Dnetary, surangular, angular, splenials
o Medial: coronoid prearticular(further inside view)
Opercular bones
cover gill cavity with rhythm of breathing
Anapsid skull fenestration
Skulls have no temporal openings (fenestrae) near the temples.
Example: Found in early amniotes and turtles. These animals have solid skulls with no extra holes beyond the eye sockets.
Diapsid skull fenestration
Skulls have two temporal fenestrae on each side. These openings lighten the skull and provide attachment points for muscles.
Example: Most modern reptiles, including lizards, snakes, crocodiles, and birds. This design allows for greater muscle attachment and jaw strength.
Synapsid skull fenestration
Skulls have a single temporal opening on each side.
Example: Mammals and their extinct relatives (like the mammal-like reptiles). This single opening provides a surface for jaw muscle attachment, aiding in powerful chewing.
What is the importance of neural crest cells?
o During early embryonic development, neural crest cells contribute to the head mesenchyme (ectomesoderm)
o Also contributing to the head mesenchyme are cells of mesodermal origin (mesodermal mesenchyme/aka embryonic connective tissue)
o The position of the mesodermal (stippled) and the neural crest (shaded) mesenchyme, and the approximate interface between them
