Neuroembryology Head & Neck

Question 1

What arises from ectoderm

Answer 1

neural crest, neural tube, epithelia of skin, nasal pit, auditory external meatus

Question 2

What arises from endoderm?

Answer 2

epithelial lining of pharynx, larynx, trachea, esophagus, pharyngotympanic tube, middle ear.
Glands: thymus, PTH, tonsils, thyroid

Question 3

What arises from the mesoderm?

Answer 3

notochord, somites –> bone, CT, muscle

Question 4

Neural Crest derivatives

Answer 4

CT and bone of face and skull
CN ganglia, DRG, PS ganglia
arachnoid, pia mater
C cell of thyroid

Question 5

5th aortic arch

Answer 5

vestigial, does not help

Question 6

What forms the auricle?

Answer 6

mesenchymal condensation of 1st and 2nd pharyngeal pouches

Question 7

1st pharyngeal cleft forms..

Answer 7

external auditory canal

Question 8

Pharyngeal arches form from..

Answer 8

neural crest cells that proliferate and migrate around sides of developing pharynx

Question 9

Smooth skin over neck form from..

Answer 9

2nd pharyngeal arch overgrowing the 3rd and 4th clefts

Question 10

What is the cervical sinus?

Answer 10

2,3,4 pharyngeal grooves merged and formed this. it is anterior to the SCMT

Question 11

CN innervating 1st arch

Answer 11

V - trigeminal

Question 12

CN innervating 2 arch

Answer 12

VII - Facial

Question 13

CN innervating 3 arch

Answer 13

IX - Glossopharyngeal

Question 14

CN innervating 4 & 6 arch

Answer 14

X - Vagus

Question 15

Skeletal derivative of 1st arch

Answer 15

Malleus, incus, Meckel’s cartilage

Question 16

Skeletal derivative of 2nd arch

Answer 16

stapes, styloid, superior half of body of hyoid (ear)

Question 17

skeletal derivative of 3rd arch

Answer 17

inferior half hyoid

Question 18

skeletal derivative of 4th arch

Answer 18

thyroid and epiglottic cartilages

Question 19

skeletal derivative of 6th arch

Answer 19

laryngeal cartilages

Question 20

Thyroid Diverticulum

Answer 20

posterior edge of 1st arch, migrates along midline

Question 21

1st pouch derivative

Answer 21

pharyngotympanic tube, middle ear

Question 22

2nd pouch derivative

Answer 22

palatine tonsil

Question 23

3rd pouch derivative

Answer 23

thymus and PTH

Question 24

4th pouch derivative

Answer 24

superior PTH glands C cells

Question 25

If 3rd and 4th pouch deficiency

Answer 25

DiGeorge Sydnrome, T cell deficiency

Question 26

What parts of the developing face form the upper and lower jaw?

Answer 26

1st pharyngeal arch

Question 27

Medial nasal swelling fuse to form..

Answer 27

external nose, philtrum of upper lip, primary palate

Question 28

Oblique facial cleft results from..

Answer 28

failure of fusion between lateral nasal swelling and maxillary process of 1st arch

Question 29

What forms the hard palate?

Answer 29

primary plate, secondary plate, lateral palatine proccess

Question 30

Cleft lip

Answer 30

failure of medial nasal and maxillary prominences

Question 31

Cleft palate

Answer 31

failure of palatine processes to fuse with each other

Question 32

tongue muscles develop from..

Answer 32

occipital myotomes

Question 33

what fuses to form anterior 2/3 of tongue?

Answer 33

lateral lingual swellings from 1st pharyngeal pouch

Question 34

what fuses to form posterior 1/3 of tongue?

Answer 34

caudal lingual swellings from 3rd and 4th arches

Question 35

taste buds from..

Answer 35

2 pharyngeal arch

Question 36

Somites formed

Answer 36

42-44 pairs by 5th week

Question 37

somites formed in regions

Answer 37

3 occipital
8 cervical
12 thoracic
5 lumbar
5 sacral
3-5 coccygeal

Question 38

Hemivertebrae

Answer 38

unilateral defects in formation of sclerotomes

Question 39

Resegmentation

Answer 39

migration and fusion of caudal half of each sclerotome towards the cephalic half of the adjacent sclerotome