skull socket mandible

Question 1

what 2 components make up the skull?

Answer 1

neurocranium and viscerocranium

Question 2

what is the neurocranium? what makes up the neurocranium?

Answer 2

the neurocranium encases the brain.

it is made up of

• membranous neurocranium
• cartilaginous neurocranium

Question 3

what makes up the membranous neurocranium? the cartilaginous cranium? what type of cells make up these bones?

Answer 3

membranous is made by flat bones

cartilaginous is made by base of the skull

these are both comprised of partly neural crest cells and partly somitomeres

Question 4

what is the viscerocranium comprised of? what type of cells make this?

Answer 4

face bones

entirely neural crest cells

Question 5

where do neural crest cells form from? in which way do they migrate?

Answer 5

neural crest cells comes from the developing neural plate

they migrate from the posterior/dorsal neural tube region to the anterior/ventral

Question 6

what bones make up the viscerocranium? what cells? what half of the blue and red skull from the power point is this area?

Answer 6

bones:

• facial bones
• mandible
• maxilla
• zygoma
• vomer
• palatine
• lacrimal
• nasal
• conchae

ALL neural crest cells

front half (blue) of the face

Question 7

list the types of cells that make up the neurocranium and which bones in the neurocranium are made up of these cells?

Answer 7

neural crest:

• temporal
• sphenoid
• ethmoid
• frontal bones

mesoderm

• temporal
• occipital
• parietal

Question 8

what are the two classifications of bone formation? what is the name for bone formation?

Answer 8

two types:

• intramembranous
• endochondral

ossification- bone formation. refers only to the mechanism by which bone is initially formed

Question 9

define intramembranous bone formation and list examples

Answer 9

• absence of cartilage
• example:
  
  • flat bones of the face and skull
  • mandible
  • clavicle

Question 10

define endochondral bone formation and list examples

Answer 10

• cartilage model precursor
• example:
  
  • long bones
  • bones of extremities
  • vertebrae
  • ethmoid
  • sphenoid

Question 11

what happens in intramembranous ossification

Answer 11

• mesenchymal cells aggregate and proliferate
• mesenchymal cells differentiate into osteoblasts and secrete osteoid at multiple centers of ossification
• osteoid is mineralized

Question 12

what happens in endochondral ossification

Answer 12

• hyaline cartilage model is used as a template during the generation of long and short bones
• mesenchymal osteoblasts for 2 ossification centers
• osteoid deposited in place of cartilage model

Question 13

how many fontanels in a new born? list them

Answer 13

6:

• anterior
• posterior
• postolateral/mastoid
• anterolateral/sphenoidal

Question 14

what is a fontanel? what is it used for? when do they fuse?

Answer 14

fontanel: unfused suture, a soft spot

allows for movement through the birth canal

should fuse at 18 months, but could last to adulthood

Question 15

define:

• cranioschisis

- craniosynostosis

Answer 15

cranioschisis:
- cranial vault fails to form

craniosynostosis
- premature closure of one or more cranial sutures

Question 16

define:

• scaphocephaly

- brachycephaly

Answer 16

scaphocephaly:

• sagittal suture fails
• expansion of the frontal and occipital bone occurs
• head shape is long and narrow

brachycephaly

• coronal suture fails
• stout skull (nose to occiput)

Question 17

define:

• plagiocephaly

- cloverleaf skull

Answer 17

plagiocephaly:

• unilateral coronal and lambdoid sutures fail
• asymmetric flattening of the side of skull

cloverleaf skull

• most cranial sutures
• FGFR3
• thanatophoric dwarfism