development of face

Question 1

what is the chondrocranium?

Answer 1

part of neurocranium formed by endochondral ossification

Question 2

what does the neurocranium develop from?

Answer 2

3 pairs of cartilage precursors: prechordal, parachordal and hypophyseal

Question 3

where does the cartilage that makes up the neurocranium come from?

Answer 3

occipital somites

Question 4

parachordal cartilages form _____

Answer 4

basioccipital

Question 5

occipital somites form ____

Answer 5

exoccipital (modified vertebral element)

Question 6

periotic capsules form _____

Answer 6

petrous and mastoid regions of temporal bones

Question 7

hypophyseal cartilages form ____

Answer 7

body of sphenoid (basisphenoid)

Question 8

posterior prechordal cartilage forms _____

Answer 8

presphenoid

Question 9

alisphenoid forms ____

Answer 9

greater wing

Question 10

orbitosphenoid and hypochiasmatic form ____

Answer 10

lesser wing

Question 11

anterior prechordal cartilage forms ______

Answer 11

ethmoid bone along with olfactory capsule

Question 12

modified epiphyseal growth plate allowing growth along A-P axis

Answer 12

spheno-occipital synchondrosis (SOS)

Question 13

what allows deformation of skull as it passes through birth canal?

Answer 13

bones of cranial vault not completely ossified and joined by fibrous sutures

Question 14

six sutures/fontanelles present at birth

Answer 14

anterior, posterior, anterolateral and posterolateral

Question 15

how is the development of the face established?

Answer 15

by development and joining of 5 prominences associated with the 1st pharyngeal arch: frontonasal, 2 maxillary and 2 mandibular

Question 16

prominences initially surround _____

Answer 16

stomodeum

Question 17

separates stomodeum from GI tract

Answer 17

oropharyngeal membrane

Question 18

further growth and expansion is dependent on _____

Answer 18

NCC proliferation

Question 19

maxillary prominences enlarge and grow ____

Answer 19

ventrally and medially

Question 20

form as bilateral oval thickenings on inferolateral aspect of frontonasal prominence

Answer 20

nasal placodes

Question 21

what do the nasal placodes eventually become?

Answer 21

nasal pits (eventually anterior nares and nasal cavity)

Question 22

horseshoes shaped elevations surrounding placodes

Answer 22

medial and lateral nasal processes

Question 23

groove between lateral nasal process and maxillary prominence

Answer 23

nasolacrimal groove

Question 24

medial nasal processes move toward midline and join to form _____

Answer 24

bridge and septum of nose

Question 25

inferior tips of medial nasal process expand laterally and inferiorly to fuse as ____

Answer 25

intermaxillary process

Question 26

intermaxillary process will give rise to _____

Answer 26

philtrum primary palate 4 upper incisors

Question 27

intermaxillary process fuses with maxillary prominence to form ____

Answer 27

upper lip

Question 28

nasal pits _____ while frontonasal _____

Answer 28

deepen and invaginate expands

Question 29

merging of medial nasal processes into intermaxillary segment joins _____ into ____

Answer 29

nasal pits single nasal sac

Question 30

separates nasal sac from oral cavity

Answer 30

nasal fin

Question 31

how does the oronasal membrane form?

Answer 31

apoptosis in fin expands nasal sac and thins fin

Question 32

oronasal membrane ruptures to form ____

Answer 32

primitive choana

Question 33

floor of nasal cavity is ______

Answer 33

primary palate from intermaxillary segment

Question 34

oral and nasal cavities will be separated by formation of _____

Answer 34

palatal shelves

Question 35

describe the formation of the palatal shelves

Answer 35

initially palatal shelves grow inferiorly from maxillary process soon they rotate superiorly into horizontal position which requires deepening of mandible and descent of tongue fusion in middle of midline and continual fusion anteriorly and posteriorly

Question 36

palatal shelves form _____

Answer 36

secondary palate

Question 37

indicates fusion of primary palate with anterior aspect of secondary palate

Answer 37

incisive foramen

Question 38

posterior aspect of secondary palate

Answer 38

soft palate

Question 39

how is the nasal septum formed?

Answer 39

down growth of medial nasal and frontonasal processes from roof of nasal cavity

Question 40

describe how the nasal cavity becomes separated into two nasal passages

Answer 40

nasal septum eventually fuses with superior aspect of primary and secondary palates

Question 41

describe primary pneumatization

Answer 41

maxillary, frontal and ethmoid sinuses develop as outgrowths of nasal cavity

Question 42

describe secondary pneumatization

Answer 42

sinuses expand through childhood and adulthood

Question 43

results from closure of sphenoethmoidal recess

Answer 43

sphenoid sinus

Question 44

describe how the parotid gland develops

Answer 44

develops from ectoderm between maxillary and mandibular prominences

Question 45

describe how sublingual and submandibular glands devleop

Answer 45

develop from endoderm lining floor of oral cavity

Question 46

name the stages of salivary gland development

Answer 46

prebud bud pseudoglandular canalicular terminal bud

Question 47

what types of hard tissue are teeth composed of?

Answer 47

enamel cementum dentine

Question 48

what forms enamel?

Answer 48

ectoderm that gives rise to ameloblasts

Question 49

what forms cementum and dentine?

Answer 49

NCCs that give rise to cementoblasts and odontoblasts

Question 50

what gives rise to vasculature of teeth?

Answer 50

mesoderm