Embryological

Question 1

Face and Palate formation

Answer 1

At week 4 the unilateral pharyngeal arches form that have pharyngeal pouches, from pouch 1- auditory tube
pouch 2- palatine tonsils
pouch 3 & 4- parathyroid, thymus glands
pouch 4- ultimobranchial body.
The face starts to take shape when 2 patches of ectoderm on the frontal prominence start to proliferate forming 2 thickenings known as nasal placodes and form a swelling inner half is called medial nasal process and the outer half is the lateral nasal process, the frontal region is called the frontal nasal process. The nasal placodes sink down causing nasal pits. The oral cavity and the maxillary processes start to proliferate towards the centre. The maxilary process fuse with the maxillary process to form the upper lip. The bridge of the nose, philtrum, 4 upper incisor teeth and primary palate forms.
The mandibula process from the lower jaw, all its teeth and the lower lip fuses with the maxillary process to form the cheeks. The nasal and oral cavity become connected in week 8.
The maxillary process develops a pair of palatine shelves on either side of the developing tongue, as the mandibular process grows and expands the tongue, as the mandibular process grows and expands the tongue moves downward allow the palatine shelves to grow medially and fuse together.

Question 2

Embryonic period

Answer 2

1.Induction
-Cellular interactions
-If disturbed no cells will grow meaning less or no less

2.Proliferation
-Development of cell- proliferate into more numbers

3. Differentiation
   -Genetically identical embryonic cells will be come distinct structurally and functionally.
4. Morphogenesis-
   -Give different shape to all these structures
   -Development of specific tissue or shape.
5. Maturation
   Attain adult size, form and function.

Question 3

3 layers

Answer 3

Ectoderm- outside layer
mesoderm- middle layer
endoderm- inside layer

Question 4

Pharyngeal pouches

Answer 4

1. Tympanic membrane, Tympanic cavity, auditory tube
2. Palatine tonsils
   3 & 4. parathyroid and thyroid glands
3. ultimobranchial body form calcitonin

Question 5

Which embryological processes will contribute to the formation of the upper lip. PTQ

Answer 5

Frontal nasal process by the medial nasal process.- philtrum
maxillary process- upper lip

Question 6

Lower lip formed by what process

Answer 6

Mandibular process

Question 7

Labial commissure formed by what process

Answer 7

maxillary and mandible processes

Question 8

Cheek formed by what process

Answer 8

maxillary and mandibular process