Development Of The Face

Question 1

The face primordial appears when and where

Answer 1

Early in the 4th week and around the stomodeum

Question 2

How may fascia primordial appear as prominences around the stomodeum; name them

Answer 2

5
> the single frontonasal prominence
> the paired maxillary prominences
> the paired mandibular prominences

Question 3

The paired facial prominences are derivatives of

Answer 3

1st pharyngeal arch

Question 4

The prominences are produced mainly by what

Answer 4

Proliferation of neural crest cells

Question 5

The neural crest cells migrate from the —— and —— of the neural fold into the pharyngeal arches during what week

Answer 5

Mesencephalon
Rhombemceohalon
Fourth week

Question 6

The —— which are two bilateral oval thickening in the surface of the ectoderm of the frontonasal prominence appear by why week

Answer 6

The nasal placodes, The end of 4th week

The nasal placode (or olfactory placode) gives rise to the olfactory epithelium of the nose. Two nasal placodes arise as thickened ectoderm from the frontonasal process. They give rise to the nose, the philtrum of the upper lip, and the primary palate.

Question 7

Nasal placodes are primordial of what

Answer 7

The nose and nasal cavities

Question 8

The shape of the nasal placodes are initially —— then later become ——

Answer 8

Convex
Stretched to produce a flat depression on each placodes

Question 9

Mesenchymes in the margins of the placodes proliferate, producing a horse-shoe shaped elevations called

Answer 9

Medial and lateral nasal prominences

Question 10

Afterwards, the nasal placodes lie in depression called

Answer 10

Nasal pits

Question 11

The nasal placodes lie in the depression called

Answer 11

Nasal pits

Question 12

These pits are the primordial of the what

Answer 12

Anterior nares (nostrils) and nasal cavity

Question 13

What is the major source of the CT components including muscles, cartilages, bone and ligaments in the facial and oral regions

Answer 13

Mesenchymal cells

Question 14

The frontonasal prominence is formed of 2 parts; name them

Answer 14

Frontal part: from the forehead
Nasal part: from therostral boundary of the stomodeum

Question 15

The paired maxillary prominences forms what

Answer 15

Lateral boundaries of the stomodeum

Question 16

The paired mandibular prominences constitute what

Answer 16

The caudal boundary of the primitive mouth

Question 17

When does the medial nasal prominence merge with each other and either the maxillary and lateral nasal prominence?

Answer 17

7th and 8th week

Question 18

Merging of the medial nasal and maxillary prominence im results in

Answer 18

Continuity of the upper jaw and upper lip stomodeum and separation of the nasal pits from the stomodeum

Question 19

What are the first parts to form the face and form

Answer 19

Lower jaw and the lower lips

Question 20

The formation of the lower jaw and lower lips are a result of

Answer 20

Merging of the medial ends of the mandibular prominences in the median plane

Question 21

Failure of the merging of medial ends of the mandibular prominence in the median plane causes what

Answer 21

Median cleft of the lower lip (very rare condition)

Question 22

Each lateral nasal prominence is separated from the maxillary prominence bt a cleft called

Answer 22

Nasolacrimal groove

Question 23

The nasolacrimal duct develops from where?

Answer 23

The rodlike thickening of ECTODERM in the floor of the nasolacrimal groove

Question 24

This thickening of ectoderm gives rise to a ——- that separates from the ectoderm and sinks into the mesenchyme

Answer 24

solid epithelial cord

Question 25

What forms the nasolacrimal duct?

Answer 25

Cell degeneration which causes the epithelial cord to canalize

Question 26

What causes oblique cleft lip

Question 27

What causes midline cleft lip

Answer 27

The failure of the medial nasal prominence and maxillary prominences to fuse