Skull Flashcards
Cranial skeleton results in
chondrocranium, splanchnocraium, dermatocranium
where is the chondrocranium from
mesoderm, neural crest
where is the splanchnocranium from
neural crest
where is the dermatocranium from
neural crest
what does cephalization result in
locomotor adaptations, placement of muscles, size fo brain areas, position of eyes, olfactory and optic abilities, posture
what forms the composite skull chondrocranium
mesoderm and some neural crest
what forms the composite skull splanchnocranium
oldest, neural crest
what forms the composite skull dermatocranium
neural crest
neural crest Essential for development of vertebrate features, such as:
jaw, mammal middle ear ossicles, shell in turtles, feathers in birders, incisors in rodents
chondrocranium - nasal, optic, and otic capsule develop from what
neural crest
Embryonic Development of the Chondrocranium
condensation of mesenchyme form cartilage, cartilage plates fuse, ossification of cartilage plates
what does the trabeculae turn into form the chondrocranium
forms ethmoid plate -> basisphenoid, prespenoid, orbitosphenoid, and mesethmoid
in mammals the sphenoid turns into
basisphenoid, pre sphenoid, and orbitosphenoid
parachordal cartilages turns into
basioccipital
occipital arches turn into
exoccipital, supraoccipital
nasal capsule turns into
ethmoturbinal, nasoturbinal, maxilloturbinal
nasal capsule is from the
neural crest
the optic capsule is from the
neural crest
optic capsule forms
sclerotic
otic capsule is from the
neural crest
otic capsule forms the
prootic, opisthotic, epizootic, pterotic, sphenotic
hyoid is from what origin
neural crest
arch 1, mandibular arch results in
epibranchial and ceratobranchial
arch 2, hyoid arch results in
spibranchial
splanchnocranium results in
dorsal - pharyngobranchial, epibranchial, ceratobranchial, hypobranchial, basibranchial - ventral
spiracle
allows
sharks and rays to
draw in water
from above even
when swimming
on ocean floor
splanchnocranium becomes ___ with evolution
smaller
what forms pharyngeal arch 1
Rhombomere 1, 2, 3
what forms pharyngeal arch 2
Rhombomere forms 3, 4, 5
what forms pharyngeal arch 3
Rhombomere 5, 6
what forms pharyngeal arch 4
Rhombomete 6, 7
what forms the spinal cord
spinal cord
Neural crest cells derived from particular ___ (neural crest)
of the ___ migrate into populate particular ___
rhombomeres, hind brain, pharyngeal arches
rhombencephalon is from what part of the brain
3rd part
the fish skull is
kinetic
important ossifications of the jaw
one ossification in hyoid, two ossification in the upper jaw, one major ossification in the lower jaw, second (mentomeckelian) is present in some species
study this
study this
Dermal Bones Covering Jaw: palatoquadrate
Dermal Bones Covering Jaw: mandibular
Dermal Bones Covering Jaw: palatal region
Evolutionary
Trend of Dermal
Bone Loss
Columella of frog is our
stapes
The quadrate is our
incus
The articular is our
malleus
evolution of bones in skull
Pelycosaurs; Synapsids, more ___
looking. Still have
___ jaw
articulation. Used to be
considered reptiles
mammal, quadrate/articular
Theraspids
3 ear ossicles
Primitive mammals + mammals
Synapsids,
dentary/squamosal
jaw articulation and
3 ear ossicles =
Mammals
Our palate is the growth
of the ___, the
___, and the ___
from the outside edges
down toward the center
premaxillia, maxilla, palatine
Advantages of having a
Secondary palate
Moved the functional
opening of the internal
nares to the back of the
mouth
Homeothermy, oxygen
needs and food needs
Secondary palate allow
for breathing and
chewing at same time
Openings of the nasal sac
internal
and external naris
Changes in jaw articulation
during the transition from
early (pelycosaurs) to late
(mammals) synapsids
Larger dentary associated with
stronger bite.
Homeothermy require more
energy - need more food, need
to be more successful as a
predator.
Double Jaw Articulation in Probainognathus,
a late Cynodont (therapsid)
Jaw articulation occurs between the quadrate and articular (solid
arrows), the primitive condition, and another articulation occurs
between dentary and squamosal (open arrow)
Evolution of
middle ear bones
in mammals
bigger to smaller
