brachial/pharyngeal arches

Question 1

what does the ectoderm form?

Answer 1

neural tube and skin

Question 2

what does the mesoderm form?

Answer 2

everything else

Question 3

what does the endoderm form? what arch does not contain endoderm?

Answer 3

gut- 1st arch

Question 4

what do NCC form?

Answer 4

migrate from neural tube to mesoderm to form H and N structures

Question 5

what are NCC cells also known as?

Answer 5

ecto-mesenchymal cells

Question 6

what is the first arch called?

Answer 6

mandibular arch

Question 7

what arteries are located within the first arch?

Answer 7

maxillary

Question 8

what nerve controls the first arch ? and what artery?

Answer 8

trigeminal nerve- CNV
hyoid artery

Question 9

what cartilage is found in the 1st arch?

Answer 9

meckels

Question 10

what bones are formed from the first arch?

Answer 10

incus and malleus

Question 11

what structure is formed by the 1st arch?

Answer 11

body of tongue

Question 12

what muscles are formed by the first arch ?

Answer 12

-muscles of mastication: temporals, masseter and pterygoing
- anterior belly of digastric
-mylohyoid
-tensor pallentini
-tensor tympani

Question 13

what syndrome occurs if NCC cells fail to migrate to the first arch?

Answer 13

Treacher collins syndrome

Question 14

what does Treacher collins syndrome cause?

Answer 14

facial bone aplasia- mandible and zygomatic bone

Question 15

what are the symptoms of teachers collins syndrome?

Answer 15

ear deformaties
dental anomalies
clefts

Question 16

what is the second arch called

Answer 16

hyoid arch

Question 17

what cartilage is found in the second arch?

Answer 17

reicharts

Question 18

what does reicharts cartilage form?

Answer 18

-stapes
-lesser horn of hyoid
-superior hyoid body
-styloid process

Question 19

what nerve controls the second arch?

Answer 19

CNVII - facial nerve

Question 20

what muscles are formed by the second arch?

Answer 20

muscles of facial expression and posterior belly of digastric muscle

Question 21

what other structures are formed by 2nd arch?

Answer 21

tonsils
thyroid gland

Question 22

what nerve controls the 3rd arch?

Answer 22

glossopharyngeal nerve- CNXI

Question 23

what does the 3rd arch form?

Answer 23

greater horn of hyoid
inferior hyoid body
root of the tongue
stylopharyngeous muscle

Question 24

what artery is formed by 3rd arch?

Answer 24

internal carotid artery

Question 25

what nerve controls the 4th arch?

Answer 25

vagus nerve CNX

Question 26

what artery is within the 4th arch?

Answer 26

subclavian artery and aorta

Question 27

what cartilage is found within the 4th arch?

Answer 27

thyroid cartilage

Question 28

what else is found in the 4th arch?

Answer 28

-pharynx
-epiglottis
-pharangeal constrictor
-soft palate

Question 29

what happens to the 5th arch?

Answer 29

it disappears fairly quickly

Question 30

what does first punch form?

Answer 30

middle ear
euchastrian tube
tympanic membrane

ventral part obliterated by tongue

Question 31

what does second pouch form?

Answer 31

tonsillar fossa
ventral part obliterated by tongue

Question 32

what does 3rd pouch form?

Answer 32

inferior parathyroid gland
thymus

Question 33

what does 4th pouch form?

Answer 33

superior parathyroid gland

Question 34

what happens to the 2nd to 6th cleft/grooves?

Answer 34

they disappear due to proliferating 2nd hyoid arch

Question 35

what happens if the grooves do not disappear and the 2nd hyoid arch does not proliferate?

Answer 35

brachial fistula/cyst
“gill-like structure”

Question 36

what is the only cleft to remain?

Answer 36

the first- forming the EAM

Question 37

what do the other proliferated clefts become?

Answer 37

cervical sinus

Question 38

what does the 4th arch form?

Answer 38

pharynx and epiglottis

Question 39

what muscles does the 4th arch form?

Answer 39

pharyngeal constrictor and soft palate