LEC48: The Branchial Arches Flashcards Preview

Structures: Part Deux > LEC48: The Branchial Arches > Flashcards

Flashcards in LEC48: The Branchial Arches Deck (67):
1

model organism for understanding human head/neck structures

chick

2

defn of branchial

of or relating to the gills or to parts of the body derived from the embryonic branchial arches and clefts

3

4 components of branchial apparatus

1) branchial arches (pharyngeal arches)
2) pharyngeal pouches
3) branchial grooves (pharyngeal clefts)
4) branchial membranes

4

when in embryogenesis do branchial arches appear?

4th week

5

how many swellings by day 28?

4

6

when does largest branchial arch appear?

day 22

7

when do ruptured membranes occur in branchial arch development?

day 26

8

which branchial arches aren't well understood?

5-6

9

how many branchial arches are there?

6

10

which branchial arches are very closely related?

6th & 4th

11

what migrates into branchial/pharyngeal arches?

neural crest cells

12

4 components of branchial arches

1) nerve
2) muscles derived from mesodermal mass of each arch
3) skeletal component- bone, cartilage, or precursor
4) artery (deriatives of aortic arch)

13

cranial nerve assoc w/ 1st branchial arch

CNV: trigeminal nerve (has 3 parts, V1, V2, V3)

14

cranial nerve assoc w/ 2nd branchial arch

CNVII: facial nerve

15

cranial nerve assoc w/ 3rd branchial arch

CNIX: glasopharyngeal nerve

16

cranial nerve assoc w/ 4th branchial arch

CNX: vagus nerve

17

cranial nerve assoc w/ 5th & 6th branchial arch

cranial root of spinal accessory n
(CN XI via Vagus)

18

where do head/neck muscles come from?

either from branchial arches or from structures that migrate into head/neck

19

where do muscles of head/neck originate from

myotomes, which're from somites

20

tongue muscles derived from?

somites

21

ocular muscles derived from?

somitomeres

22

what surrounds area of developing inner ear?

meckel's cartilage & reichert's cartilage

23

where is meckel's cartilage derived from? what does it become?

from branchial arch I
precursor of mandible

24

ear bones?

malleus, incus, stapes

25

ear bones from 1st branchial arch?

upper pt of malleus, incus

26

ear bones from 2nd branchial arch?

bottom pt of malleus and incus; arch of stapes

27

muscles derived from 1st branchial arch

1) muscles of mastication: masseter, temporalis, lateral pterygoid, medial pterygoid

2) mylohyoid
3) ant. belly of digastric
4) tensor veli palatini
5) tensor tympani

28

skeletal elements of 1st branchial arch

1) head of malleus
2) upper part of incus
3) meckel's cartilage - mandible precursor

29

artery components of 1st branchial arch

1) 1st pair of aortic arches
2) remaining pts of maxillary aa
3) may contribute to ext. carotid aa

30

first branchial arch is aka

mandibular arch

31

second branchial arch is aka

hyoid arch

32

muscle derivatives of 2nd branchial arch

1) facial expression
2) stapedius
3) stylohyoid
4) post. belly of digastric

33

skeletal elements of 2nd branchial arch

1) handle of malleus
2) lower part of incus
3) arcs of stapes
4) styloid process
5) lesser cornu, upper body of hyoid

34

why is CNVII path important?

if have lesions to facial nerve, get Bell's Palsy- effects muscles of facial expression, location matters

35

relationship between CNIX and CNX?

CNIX= glossopharyngeal n
shares forebrain stem nuclei w/ CNX, vagus n. - tied in fxn

36

nerve of gag reflex?

CNIX, glossopharyngeal n

37

muscle related to 3rd branchial arch?

stylopharyngeus m

38

skeletal elements of 3rd branchial arch

greater horn (cornu) of hyoid; lower part of body of hyoid

39

artery of 3rd branchial arch

1) 3rd pair of aortic arches
2) proximal pts: common carotid aa
3) distal pts: pts of int carotid aa

40

muscles related to 4th branchial arch?

cricothyroid - and others it shares its innervation w/:
levator veli palatini
pharyngeal constrictors
palatoglossus
salpingopharyngeus
palatopharyngeus

41

skeletal components related to 4th branchial arch?

laryngeal cartilages

42

artery of 4th branchial arch?

1) 4th pair of aortic arches
2) left arch- pt of aortic arch
3) right arch- part of R subclavian a

43

which aortic arch is L subclavian a derived from?

NONE! it's not derived from an aortic arch

44

muscles of 5th & 6th branchial arches

1) all intrinsic muscles of larynx except cricothyroid
2) levator veli palatini
3) palatoglossus
4) pharyngeal constrictors
5) salpingopharyngeus
6) palatopharyngeus

45

skeletal components of 5th & 6th brancial arches

laryngeal cartilages

46

artery of 5th & 6th branchial arches

1) 5th or 6th pair of aortic arches
2) L & R proximal parts persist as proximal pumonary aa

L distal - ductus arteriosus
R distal - degenerates

47

what is ductus arteriosus derived form?

L distal 6th branchial arch

48

what are pharyngeal pouches derived from?

endoderm

49

function of pharyngeal pouches in embryo?

line inside of developing embryo

50

derivative of 1st pharyngeal pouch?

inner workings of ear:
1) tubotympanic recess: prox part- auditory (pharyngotympanic) tube;
2) distal pt- middle ear cavity & mastoid antrum

51

derivatives of 2nd pharyngeal pouch?

mostly obliterated

not obliterated pt > crypts of palatine tonsil

52

derivatives of 3rd pharyngeal pouch?

ventral pt- primordia of THYMUS
dorsal pt- inf parathyroid glands

53

derivatives of 4th pharyngeal pouch?

ventral pt- ultimobranchial body (fuses w/ thyroid glands)
dorsal pt- sup parathyroid glands

maybe portions of lat thyroid gland

54

derivatives of 5th pharyngeal pouch?

usu considered pt of 4th ultimobranchial body

55

what persists from pharyngeal clefts/branchial grooves? which cleft's it from?

ONLY external acoustic meatus
from 1st pharyngeal cleft

56

what happens to 2nd-4th pharyngeal clefts?

temporarily exist as common cervical sinus; usu disappears; may become branchial sinus / branchial fistula

57

what are branchial membranes

pt of branchial apparatus
appear where epithelia of a branchial groove & pharyngeal pouch approach each other

58

what in adults persists from branchial membranes?

from 1st branchial membrane, only 1 pair: tympanic membrane

59

what might persist from pharyngeal clefts, in baby?

complete fistula aka branchial cyst
presents as oozing from side of neck

60

what's mandibular hypoplasia?

1st arch problem
failure of meckel's cartilage, failure of upper portions of malleus, incus to develop

61

what/when does 1st endocrine gland appear in embryo?

thyroid gland, day 24

62

where does thyroid gland descend from?

foramen cecum - point in the tongue

63

descent path of thyroid gland?

from foramen cecum in tongue > chisels through tongue > descends down anterior part of neck > anterior pt of neck finally

64

cause of malformation/variation in thyroid?

as descends down anterior pt of neck, things may be in its way

65

what might be in way of thyroid gland as descends?

1) pyramidal lobes/persistent thyroglossal ducts
2) thyroglossal duct cysts & sinuses
3) ectopic thyroid gland

66

where might get cyst in neck re: thyroid?

thyroglocil duct

67

name the 4 muscles of mastication

masseter, temporalis, lateral pterygoid, medial pterygoid