Lecture 38 - Pharyngeal arches Flashcards Preview

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Flashcards in Lecture 38 - Pharyngeal arches Deck (57):
0

What are the two fates of the epiblast cells?

1) fill in between epiblast and hypoblast
2) replace hypoblast cells

1

What do the epiblast cells become after they replace hypoblast cells?

Endoderm

2

What do epiblasts become when they fill in between the epiblasts and hypoblasts?

Intraembryonic mesoderm

3

What does the rest of the epiblast cells become who dont invaginate?

Ectoderm

4

What does the notochord cause in the ectoderm?

Neural plate

5

What are the two ridges that form in the neural plate?

Neural folds
Neural groove

6

What grows at the tips of the neural folds?

Neural crest cells

7

What do the growth of somites cause?

Lateral folding of the trilaminar disc

8

What causes crainocaudal folding of the trilaminar disc?

Longitudinal growth of cranial and caudal ends of the neural plate tube

9

What is the oropharyngeal membrane?

Separates the pharynx from the oral cavity

10

Where does the oropharyngeal membrane start out?

Cranial to the developing neural tube

11

Where are the pharyngeal arches located?

Paired bulges along the call of the developing pharynx

12

What is the outer surface of the arches made of?

Ectoderm

13

What is the inner surface of the pharyngeal arches?

Endoderm

14

What is the middle of the pharyngeal arches made from?

Mesenchyme from paraxial and lateral plate mesoderm and neural crest cells

15

What are the numbers of the arches?

1 - 2 - 3 - 4 - 6

16

What does the mesoderm from the pharyngeal arches become?

Muscles of the head

17

What do the neural crest cells of the pharyngeal arches become in the head?

Skeleton of the head and neck

18

What is the nerve for arch 1?

CN V - Trigeminal

19

What is the nerve for arch 2?

CN VII - Facial n.

20

What is the nerve for arch 3?

CN IX - Glossopharyngeal

21

What is the nerve for arch 4?

CN X - Cranial laryngeal

22

What is the nerve for arch 6?

CN X - Caudal laryngeal

23

What are the two parts of the first arch?

Maxillary
-- and --
Mandibular

24

What is the cartilage of the first arch?

Meckel's cartilage

25

What is the fate of the Meckel's cartilage of the first arch?

Malleus
-- and --
Incus

26

What does the mesenchyme from the neural crest cells of arch 1 become?

Bones of the mandible and lower face - via membranous ossification

27

What does the mesoderm derived mesenchyme of the first arch become?

Dermis of the face and muscles of the mandible and ear

28

What are the muscles innervated by the first arch?

Muscles of mastication
Tensor typani and tensor veli palatini
Skin of face

29

What does the cartilage of the second arch articulate with?

Dorsal edge articulates with meckel's cartilage

30

What does the cartilage of the second arch become?

Cranial part of hyoid apparatus (Stylohyoid, epihyoid, ceratohyoid, and cranial part of basihyoid)
Stapes

31

What muscles come from the second arch?

Stylohyoideus and caudal digastric
Stapedius
Muscles of facial expression

32

What happens to some of the muscles of facial expression from the second arch?

Migrate to the arch 1 territory

33

What comes from arch 3?

Thyrohyoid and caudal portion of the basihyoid
Stylopharyngeus

34

What comes from arch 4?

Cartilages of the larynx
Cricothyroid and pharyngeal muscles

35

What comes from arch 6?

Intrinsic muscles of the larynx - except cricothyroid

36

What is the area between the pharyngeal archs called?

Externally - Clefts
Internally - Pouches

37

What many internal pouches are there?

4

38

How many external clefts are there?

1

39

What does the external cleft become?

External auditory canal

40

What does the first pharyngeal pouch become?

Tympanic cavity
-- and --
Pharyngotympanic tube

41

What forms where the pouch and the cleft join?

Tympanic membrane

42

What does pouch 2 become?

Tonsils

43

What does pouch 3 become?

Glands

44

What does pouch 4 become?

C cells to the thyroid gland

45

What does the second arch form when it overgrows?

leaves pocket of tissue in the developing neck - cervical sinus

46

What happens when there is a failure in the cervical sinus degenerating?

Cervical cysts in adults

47

What happens when there is a failure in the fusing of arch 2 and distal lateral cervical tissue?

Result in fistulas that may connect to the cervical cysts

48

What is the primitive oral opening called?

Stomodeum

49

What are within the nasal placodes?

Nasal pits

50

What is the major characteristics of nasal pits?

Depression left in the middle of placode as surrounding mesenchyme proliferates

51

What is the origin of the incisive bone?

Intermaxillary segemnt - fused medial nasal prominences

52

What are the four regions of the tongue?

Lateral lingual swelling
Tuberculum inpar
Copula
Epiglottal swelling

53

What is made from arch 1?

Lateral lingual swellings
-- and --
Tuberculum impar

54

What is the copula made from?

Arches 2, 3, and 4

55

What makes up the epiglottal swelling?

Arch 4

56

What are occipital somites?

Some mesoderm migrates in to teh developing tongue to produce the muscle and somite innervation is preserved