Pharyngeal (Brachial) Arches

Question 1

what does ectoderm give rise to

Answer 1

skin and neural tube

Question 2

what does ectoderm come from

Answer 2

form epiblast layer

Question 3

what does mesoderm layer give rise to

Answer 3

just about everything else

Question 4

where does mesoderm come from

Answer 4

migratory cells of epiblast layer

Question 5

what does endoderm give rise to

Answer 5

gut

Question 6

what does endoderm come form

Answer 6

from hypoblast layer

Question 7

what sit he neural crest / ecto-mesenchyme come from

Answer 7

from ectoderm that migrates into mesoderm to form structures of head and neck

Question 8

what is the opening for the mouth called

Answer 8

stomatodeum

Question 9

how long until PA form

Answer 9

20 days

Question 10

what does the PA give rise to

Answer 10

most head and neck region

Question 11

when is all head and neck prod

Answer 11

56 days

very rapid dev

Question 12

at 28 days what can be seen structure of embryo

Answer 12

fronto-nasal prominence
stomatodeum
PA
cardiac swelling

Question 13

what can be seen on frontonasal prominence

Answer 13

lens placode

Question 14

when do PA appear

Answer 14

4th - 5th week

Question 15

what is the PA

Answer 15

bars of ecto-mesenchymal tissue migrate in

Question 16

what are the arches sep by

Answer 16

clefts/grooves - externally and pouched internally

Question 17

whtare th genes of the PA that control dev

Answer 17

hoxabox genes

which allow cells to differentiate correctly

Question 18

what are the PA branches numbered

Answer 18

1 2 3 4 6

Question 19

why is there no PA 5

Answer 19

doesn’t exist in humans

sometimes appears as swelling but dissaears

Question 20

what does a PA consist of

Answer 20

ectoderm - outside 
endoderm - inside except PA  1
cartilage 
blood vessels and nerve
muscle

Question 21

what is the 1st arch

Answer 21

mandibular arch

Question 22

what des the mand arch give rise to

Answer 22

mandible and max processes 
body tongue 
muscle mast 
Trigeminal 
max and carotid A's

Question 23

what is the cartilage in the 1st arch

Answer 23

meckels cart

Question 24

what is meckels cart

Answer 24

primitive support

largely disappears

Question 25

what does merckels cart form

Answer 25

2 bones - incus and malleus | 2 ligaments - sphenomand, sphenomalleolar

Question 26

what is the mutation of PA 1

Answer 26

teacher collins syndrome

Question 27

what causes teacher collins syndrome

Answer 27

can be single polymorphism | neural crest doesn't form properly so abnormal form and and zygoma

Question 28

what happens in teacher collins

Answer 28

``` fail neural crest migration facial bone hypoplasia ear abnormalities clefts dental anomalies ```

Question 29

what are some dental anomalies that can occur in teacher collins syndrome

Answer 29

tooth agencies enamel deformitits misplacement upper 6's

Question 30

what is the 2nd arch

Answer 30

hyoid arch

Question 31

what si the crat of PA 22

Answer 31

Reicharts cart

Question 32

what does reicharts arch form

Answer 32

stapes lesser horn and sup hyoid body styloid process stylohyoid ligament

Question 33

what else is present from the PA 2

Answer 33

``` facial expression muscles PBD thyroid gland tonsil facial nerve ```

Question 34

what doe the PA 3 form

Answer 34

``` greater horn hyoid inf hyoid body root tongue stylopharyngeus glossopharyngeal ```

Question 35

what does PA 4 form

Answer 35

``` thyroid cart pharynx epiglottis pharyngeal constrictor soft palate vagus - sup laryngeal nerve ```

Question 36

what does PA 6 form

Answer 36

cricoid and arytenoid cart larynx muscles larynx vagus - inf laryngeal

Question 37

what does the 1st groove form

Answer 37

EAM and ear drum

Question 38

what happens to the 2nd - 6th clefts

Answer 38

disappear | obliterated by proliferating 2nd arch

Question 39

what des the 1st pouch form

Answer 39

eustachian tube middle ear cav tymp mem ventral part obliterate by tongue

Question 40

what does the 2nd pouch form

Answer 40

tonsillar fossa | ventral part obliterated by tongue

Question 41

what does 3rd pouch form

Answer 41

inf parathyroid gland nd thymus

Question 42

what does 4th pouch form

Answer 42

sup parathyroid gland

Question 43

what is formed with the remnants of the 2nd-4th clefts

Answer 43

cervicalsinus

Question 44

where are pharyngeal membranes found

Answer 44

in the floor of the pharyngeal grooves

Question 45

where do the pharyngeal mems form

Answer 45

where epi of grooves and pouches approach each other

Question 46

what separates the endoderm and ectoderm

Answer 46

mesenchyme

Question 47

what PA mem become

Answer 47

tymp mem others obliterate

Question 48

what is brachial fistula/cyst

Answer 48

2nd arch fails to grow down sufficiently over 2nd and 4th clefts along ant border of SCM

Question 49

what is ectopic thyme or parathyroid tissue

Answer 49

failure to migrate completely