LEC48: The Branchial Arches Flashcards Preview

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

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

model organism for understanding human head/neck structures

A

chick

2
Q

defn of branchial

A

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

3
Q

4 components of branchial apparatus

A

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

4
Q

when in embryogenesis do branchial arches appear?

A

4th week

5
Q

how many swellings by day 28?

A

4

6
Q

when does largest branchial arch appear?

A

day 22

7
Q

when do ruptured membranes occur in branchial arch development?

A

day 26

8
Q

which branchial arches aren’t well understood?

A

5-6

9
Q

how many branchial arches are there?

A

6

10
Q

which branchial arches are very closely related?

A

6th & 4th

11
Q

what migrates into branchial/pharyngeal arches?

A

neural crest cells

12
Q

4 components of branchial arches

A

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
Q

cranial nerve assoc w/ 1st branchial arch

A

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

14
Q

cranial nerve assoc w/ 2nd branchial arch

A

CNVII: facial nerve

15
Q

cranial nerve assoc w/ 3rd branchial arch

A

CNIX: glasopharyngeal nerve

16
Q

cranial nerve assoc w/ 4th branchial arch

A

CNX: vagus nerve

17
Q

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

A

cranial root of spinal accessory n

CN XI via Vagus

18
Q

where do head/neck muscles come from?

A

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

19
Q

where do muscles of head/neck originate from

A

myotomes, which’re from somites

20
Q

tongue muscles derived from?

A

somites

21
Q

ocular muscles derived from?

A

somitomeres

22
Q

what surrounds area of developing inner ear?

A

meckel’s cartilage & reichert’s cartilage

23
Q

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

A

from branchial arch I

precursor of mandible

24
Q

ear bones?

A

malleus, incus, stapes

25
Q

ear bones from 1st branchial arch?

A

upper pt of malleus, incus

26
Q

ear bones from 2nd branchial arch?

A

bottom pt of malleus and incus; arch of stapes

27
Q

muscles derived from 1st branchial arch

A

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
Q

skeletal elements of 1st branchial arch

A

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

29
Q

artery components of 1st branchial arch

A

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

30
Q

first branchial arch is aka

A

mandibular arch

31
Q

second branchial arch is aka

A

hyoid arch

32
Q

muscle derivatives of 2nd branchial arch

A

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

33
Q

skeletal elements of 2nd branchial arch

A

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

34
Q

why is CNVII path important?

A

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

35
Q

relationship between CNIX and CNX?

A

CNIX= glossopharyngeal n

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

36
Q

nerve of gag reflex?

A

CNIX, glossopharyngeal n

37
Q

muscle related to 3rd branchial arch?

A

stylopharyngeus m

38
Q

skeletal elements of 3rd branchial arch

A

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

39
Q

artery of 3rd branchial arch

A

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

40
Q

muscles related to 4th branchial arch?

A
cricothyroid - and others it shares its innervation w/: 
levator veli palatini 
pharyngeal constrictors 
palatoglossus
salpingopharyngeus 
palatopharyngeus
41
Q

skeletal components related to 4th branchial arch?

A

laryngeal cartilages

42
Q

artery of 4th branchial arch?

A

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

43
Q

which aortic arch is L subclavian a derived from?

A

NONE! it’s not derived from an aortic arch

44
Q

muscles of 5th & 6th branchial arches

A

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

45
Q

skeletal components of 5th & 6th brancial arches

A

laryngeal cartilages

46
Q

artery of 5th & 6th branchial arches

A

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
Q

what is ductus arteriosus derived form?

A

L distal 6th branchial arch

48
Q

what are pharyngeal pouches derived from?

A

endoderm

49
Q

function of pharyngeal pouches in embryo?

A

line inside of developing embryo

50
Q

derivative of 1st pharyngeal pouch?

A

inner workings of ear:

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

51
Q

derivatives of 2nd pharyngeal pouch?

A

mostly obliterated

not obliterated pt > crypts of palatine tonsil

52
Q

derivatives of 3rd pharyngeal pouch?

A

ventral pt- primordia of THYMUS

dorsal pt- inf parathyroid glands

53
Q

derivatives of 4th pharyngeal pouch?

A

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

maybe portions of lat thyroid gland

54
Q

derivatives of 5th pharyngeal pouch?

A

usu considered pt of 4th ultimobranchial body

55
Q

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

A

ONLY external acoustic meatus

from 1st pharyngeal cleft

56
Q

what happens to 2nd-4th pharyngeal clefts?

A

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

57
Q

what are branchial membranes

A

pt of branchial apparatus

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

58
Q

what in adults persists from branchial membranes?

A

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

59
Q

what might persist from pharyngeal clefts, in baby?

A

complete fistula aka branchial cyst

presents as oozing from side of neck

60
Q

what’s mandibular hypoplasia?

A

1st arch problem

failure of meckel’s cartilage, failure of upper portions of malleus, incus to develop

61
Q

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

A

thyroid gland, day 24

62
Q

where does thyroid gland descend from?

A

foramen cecum - point in the tongue

63
Q

descent path of thyroid gland?

A

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

64
Q

cause of malformation/variation in thyroid?

A

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

65
Q

what might be in way of thyroid gland as descends?

A

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

66
Q

where might get cyst in neck re: thyroid?

A

thyroglocil duct

67
Q

name the 4 muscles of mastication

A

masseter, temporalis, lateral pterygoid, medial pterygoid