Head and neck embryology

Question 1

what do we call a ball of cells

Answer 1

blastula

Question 2

after formation of trilaminar disc what happens

Answer 2

ectoderm in the midline folds down to form neural tube which forms brain and spinal cord

Question 3

what are pharyngeal/ branchial arches

Answer 3

Series of arches which develop around the future mouth. Face and neck develop from them

Question 4

which brachial arch disappears

Answer 4

6 arches develop but number 5 disappears

Question 5

which tissues make up the branchial arches

Answer 5

ectoderm lines the outside
mesoderm lies in the middle forming cartilage and muscle
endoderm forms pouches between the arches

Question 6

what nerves forms from the 1st brachial arch

Answer 6

Mandibular branch of trigeminal

Question 7

what nerves forms from the 2nd brachial arch

Answer 7

facial nerve

Question 8

what nerves forms from the 3rd brachial arch

Answer 8

glossophargyneal nerve

Question 9

what nerves forms from the 4th brachial arch

Answer 9

superior laryngeal branch of vagus

Question 10

what nerves forms from the 6th brachial arch

Answer 10

recurrently laryngeal branch of vagus

Question 11

which arch do facial muscles develop from

Answer 11

2nd arch as all innervated by the facial nerve

Question 12

which arch does posterior and anterior digastric muscle develop from

Answer 12

anterior is the first arch and posterior is the 2nd arch

Question 13

Other structures that develop from brachial arch

Answer 13

tongue, thyroid gland, parathyroid gland, part of the pituitary gland

Question 14

describe the development of the face

Answer 14

frontonasal process
two maxillary processess
two mandibular processes
two mandibular processes fuse in the midline

Question 15

how is the nostril formed

Answer 15

ectodermal thickening, pushes inwards or invaginate to form the nasal pit
Further grows downwards and laterally to from the philtrum

Question 16

development of palate

Answer 16

1. medical nasal process grows downwards forming philtrum
2. from maxillary process two palatine shelves grow inwards
3. palatine shelves meet in the midline to from a secondary plate
4. oral cavity and nasal cavity are now separate

Question 17

how are flat bone formed

Answer 17

members bones formed by membranous ossification calvaria

Question 18

how are irregular bones formed

Answer 18

endochondral ossification

Question 19

how is the viscerocranium formed

Answer 19

partly from branchial arches and partly from sensory capsules