Formation of the face, tongue and oral cavity

Question 1

What is the order of formative events?

Answer 1

Face, Tongue then oral cavity

Question 2

formation

Answer 2

an organization level involved in the growth and development of an organ and an organism (what happens in the face and oral cavity)

Question 3

growth

Answer 3

increase in weight and spatial dimension (shape) that an organ or organism undergo

Question 4

development

Answer 4

the growth of an organ or organism through various morphological stages on its way to maturity

Question 5

what is the crown to rump measurement in the 3rd embryonic week?

Answer 5

3 mm

Question 6

what is the crown to rump measurement in the 8th fetal week?

Answer 6

30 mm

Question 7

when does the stomodeum appear?

Answer 7

in the third week

Question 8

what does the stomodeum become?

Answer 8

the oral and nasal cavities between the 6th and 8th embryonic week

Question 9

what are the boundaries of the stomodeum during the 3rd embryonic week?

Answer 9

superior: frontal prominence
inferior: cardiac plate
posterior: buccopharyngeal membrane

Question 10

what is the buccopharyngeal membrane?

Answer 10

a double membrane with epithelium on the outside and endoderm on the inside

Question 11

when do the branchial arches and clefts (or grooves) appear and then disappear?

Answer 11

embryonic week 4 (and there are 4 of them)

Question 12

what are other names for branchial arches?

Answer 12

pharyngeal or visceral arches

Question 13

what does arch 1 become?

Answer 13

right and left maxillary facial processes and right and left mandibular facial processes

Question 14

how does the commisura labiorum oris form?

Answer 14

where the maxillary and mandibular processes meet at either side of the stomodeum

Question 15

what does cleft 1 and pouch 1 become?

Answer 15

cleft 1 becomes external auditory meatus and pouch 1 becomes the eustachian tube

Question 16

what are the boundaries of the stomodeum during the 4th embryonic week?

Answer 16

superior: median and right and left lateral nasal facial processes
inferior: mandibular facial process
posterolateral: maxillary facial process

Question 17

what forms that gives rise to the 3 components of the facial process?

Answer 17

the nasal pits that appear in the frontal prominence

Question 18

what are the 3 components of the frontal prominence in the 4th embryonic week?

Answer 18

median, right and left lateral facial processes

Question 19

what is the progression of the nasal pits?

Answer 19

the nasal pits deepen and form ducts that open into the stomodeum. these ducts become nostrils that open into nasal cavities during the formation of the nasal and oral cavities

Question 20

what forms the face?

Answer 20

the frontal prominence (3 of the 7 facial processes) and the branchial arch 1 (4 of the 7)

Question 21

what is the fate of the median nasal facial process?

Answer 21

• midline of the nose

* philtrum of the upper lip

Question 22

what is the fate of the lateral nasal facial processes?

Answer 22

• ala and latearl side of the nose

* infraorbital face

Question 23

what do the maxillary facial processes become?

Answer 23

• upper part of cheek

* lateral upper lip

Question 24

what do the mandibular facial processes become?

Answer 24

• lower lip
• lower cheek
• chin

Question 25

what is mesenchyme?

Answer 25

embryonic connective tissue that has a lot of stem cells

Question 26

what does arch II become?

Answer 26

an embryonic fold of tissue (mesenchyme on the inside and epithelium on the outside) called the operculum that covers arches III, IV and celfts II, III and IV

Question 27

what does the operculum become in the adult?

Answer 27

sides of the neck below the external auditory meatus

**if fusal doesn’t occur then cysts develop

Question 28

merge vs. fusal

Answer 28

merge is mesenchyme flowing and fusal is epithelium

Question 29

how do cleft lips (unilateral and bilateral) occur?

Answer 29

• if the median nasal and maxillary processes don’t merge
• if the mandibular processes don’t merge (rare)
• ** cleft lips will happen by the 5th embryonic week

Question 30

the primary palate is on what side of the median nasal process?

Answer 30

stomodeum side

Question 31

what happens to the buccopharyngeal membrane?

Answer 31

ruptures during the 4th week to become the anterior pillar of the fauces. It opens to the foregut which become the nasal and oral pharynx

Question 32

what forms the tongue?

Answer 32

4 lingual swellings merge on the ventral side of the branchial arches during week 4 when the buccopharyngeal membrane ruptures

Question 33

what are the 4 lingual swellings and where are they located ?

Answer 33

right lateral and left lateral lingual swellings and tuberculum impar form on arch I (mandibular) and copula forms on arches 2 and 3

Question 34

what do the right and left lateral lingual swellings and tuberculum impar form?

Answer 34

anterior 2/3 of the tongue

Question 35

what does the copula form?

Answer 35

posterior 1/3 (or root) of the tongue

Question 36

where does the thyroid gland start?

Answer 36

at foramen cecum

Question 37

what is Waldeyer’s ring?

Answer 37

the ring of protection (lymph nodes) that encircle the entrance to the body made of palatine, lingual and adenoid tonsils

Question 38

tongue in the 5th embryonic week

Answer 38

• is in the stomodeum until it begins to be partitioned in the 6th embryonic week
• tongue starts tall and palatine folds are vertical and lateral to the tongue but as the face moves forward and down the tongue drops and the palatine folds move to horizontal over the tongue

Question 39

where does the primary palate arise from?

Answer 39

inside median nasal process

Question 40

where does the nasal septum arise from?

Answer 40

primary palate

Question 41

where do the palatine folds come from?

Answer 41

the inside of the maxillary facial processes

Question 42

what are all things in the head derived from?

Answer 42

ectoderm (ectomesenchyme)

**except enamel (epithelium)

Question 43

what are the palatine folds made of (and nasal septum) ?

Answer 43

ectomesenchyme with an epithelial lining
(mesenchyme that originates in the ectoderm germ layer)
**cysts can form along fusion

Question 44

what shape do the palatine fold and primary palate form?

Answer 44

Y

Question 45

what is the progression of epithelial fusal to form the remainder of the palate?

Answer 45

primary palate fuses with anterior palatine folds to form arm of the Y (5th week) and then the palatine fold and nasal septum all start to fuse continuing posteriorly until week 8 (like a zipper)

Question 46

mesenchyme union

Answer 46

when the epithelium breaks up and the mesenchyme of one structure intermingles with another
** both primary palate and palatine folds as well as palatine folds with eachother

Question 47

once mesenchymal union is complete what is formed?

Answer 47

secondary palate with oral and nasal cavities