Lecture 38 - Pharyngeal arches

Question 0

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

Answer 0

Endoderm

Question 1

What are the two fates of the epiblast cells?

Answer 1

1) fill in between epiblast and hypoblast

2) replace hypoblast cells

Question 2

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

Answer 2

Intraembryonic mesoderm

Question 3

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

Answer 3

Ectoderm

Question 4

What does the notochord cause in the ectoderm?

Answer 4

Neural plate

Question 5

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

Answer 5

Neural folds

Neural groove

Question 6

What grows at the tips of the neural folds?

Answer 6

Neural crest cells

Question 7

What do the growth of somites cause?

Answer 7

Lateral folding of the trilaminar disc

Question 8

What causes crainocaudal folding of the trilaminar disc?

Answer 8

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

Question 9

What is the oropharyngeal membrane?

Answer 9

Separates the pharynx from the oral cavity

Question 10

Where does the oropharyngeal membrane start out?

Answer 10

Cranial to the developing neural tube

Question 11

Where are the pharyngeal arches located?

Answer 11

Paired bulges along the call of the developing pharynx

Question 12

What is the outer surface of the arches made of?

Answer 12

Ectoderm

Question 13

What is the inner surface of the pharyngeal arches?

Answer 13

Endoderm

Question 14

What is the middle of the pharyngeal arches made from?

Answer 14

Mesenchyme from paraxial and lateral plate mesoderm and neural crest cells

Question 15

What are the numbers of the arches?

Answer 15

1 - 2 - 3 - 4 - 6

Question 16

What does the mesoderm from the pharyngeal arches become?

Answer 16

Muscles of the head

Question 17

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

Answer 17

Skeleton of the head and neck

Question 18

What is the nerve for arch 1?

Answer 18

CN V - Trigeminal

Question 19

What is the nerve for arch 2?

Answer 19

CN VII - Facial n.

Question 20

What is the nerve for arch 3?

Answer 20

CN IX - Glossopharyngeal

Question 21

What is the nerve for arch 4?

Answer 21

CN X - Cranial laryngeal

Question 22

What is the nerve for arch 6?

Answer 22

CN X - Caudal laryngeal

Question 23

What are the two parts of the first arch?

Answer 23

Maxillary
– and –
Mandibular

Question 24

What is the cartilage of the first arch?

Answer 24

Meckel's cartilage

Question 25

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

Answer 25

Malleus -- and -- Incus

Question 26

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

Answer 26

Bones of the mandible and lower face - via membranous ossification

Question 27

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

Answer 27

Dermis of the face and muscles of the mandible and ear

Question 28

What are the muscles innervated by the first arch?

Answer 28

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

Question 29

What does the cartilage of the second arch articulate with?

Answer 29

Dorsal edge articulates with meckel's cartilage

Question 30

What does the cartilage of the second arch become?

Answer 30

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

Question 31

What muscles come from the second arch?

Answer 31

Stylohyoideus and caudal digastric Stapedius Muscles of facial expression

Question 32

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

Answer 32

Migrate to the arch 1 territory

Question 33

What comes from arch 3?

Answer 33

Thyrohyoid and caudal portion of the basihyoid | Stylopharyngeus

Question 34

What comes from arch 4?

Answer 34

Cartilages of the larynx | Cricothyroid and pharyngeal muscles

Question 35

What comes from arch 6?

Answer 35

Intrinsic muscles of the larynx - except cricothyroid

Question 36

What is the area between the pharyngeal archs called?

Answer 36

Externally - Clefts | Internally - Pouches

Question 37

What many internal pouches are there?

Answer 37

4

Question 38

How many external clefts are there?

Answer 38

1

Question 39

What does the external cleft become?

Answer 39

External auditory canal

Question 40

What does the first pharyngeal pouch become?

Answer 40

Tympanic cavity -- and -- Pharyngotympanic tube

Question 41

What forms where the pouch and the cleft join?

Answer 41

Tympanic membrane

Question 42

What does pouch 2 become?

Answer 42

Tonsils

Question 43

What does pouch 3 become?

Answer 43

Glands

Question 44

What does pouch 4 become?

Answer 44

C cells to the thyroid gland

Question 45

What does the second arch form when it overgrows?

Answer 45

leaves pocket of tissue in the developing neck - cervical sinus

Question 46

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

Answer 46

Cervical cysts in adults

Question 47

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

Answer 47

Result in fistulas that may connect to the cervical cysts

Question 48

What is the primitive oral opening called?

Answer 48

Stomodeum

Question 49

What are within the nasal placodes?

Answer 49

Nasal pits

Question 50

What is the major characteristics of nasal pits?

Answer 50

Depression left in the middle of placode as surrounding mesenchyme proliferates

Question 51

What is the origin of the incisive bone?

Answer 51

Intermaxillary segemnt - fused medial nasal prominences

Question 52

What are the four regions of the tongue?

Answer 52

Lateral lingual swelling Tuberculum inpar Copula Epiglottal swelling

Question 53

What is made from arch 1?

Answer 53

Lateral lingual swellings -- and -- Tuberculum impar

Question 54

What is the copula made from?

Answer 54

Arches 2, 3, and 4

Question 55

What makes up the epiglottal swelling?

Answer 55

Arch 4

Question 56

What are occipital somites?

Answer 56

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