Head and Neck development

Question 1

When does the bilateral pharyngeal apparatus start to form?

Answer 1

Four to five weeks post fert

Question 2

Pharyngeal clefts

Answer 2

External aspect between arches (ectoderm)

Question 3

Pharyngeal pouch

Answer 3

internal aspect between arches. There are four well defined arches, the fifth is reabsorbed. (endoderm)

Question 4

Pharyngeal membranes

Answer 4

2 layered structures of ectoderm and endoderm

Question 5

What is in the mesenchymal core of the arches?

Answer 5

Paraxial mesoderm, nc cells, and lateral plate mesoderm.

Question 6

What does each pharyngeal arch contain?

Answer 6

A cartilaginous skeletal component(nc cell derived) connective tissue (nc cells) and muscle component (paraxial) a cranial nerve and a aortic arch artery

Question 7

Intramembranous bone formation

Answer 7

Bone develops in WELL vascularized mesenchyme. No cartilage model. Makes flat bones of face and skull

Question 8

Intra cartilaginous bone formation

Answer 8

Bone forms from pre-existing cartilage model, SOME bones of the pharyngeal apparatus are made this way

Question 9

What are the two prominces of the 1st pharyngeal arch

Answer 9

Maxillary and Madibular

Question 10

Describe the cartilagenous component of the maxillary promincence of the 1st arch

Answer 10

The cartilage is called the palatopterygoquadrate (HOLY FUCK THAT IS A WORD) and the cartilage regresses and leaves no adult remnant

Question 11

Describe the cartilagenous component of the mandibular prominence of the 1st pharyngeal arch

Answer 11

It is called Meckel’s cartilage and it makes a large contribution to the face, it leaves SOME adult structures

Question 12

What does meckel’s cartilage give rise to? and how?

Answer 12

Incus, malleus, by endochondral ossification

Question 13

What does the perichondrium of Meckel’s cartilage form?

Answer 13

Anterior ligament of malleus, and Sphenomandibular ligament

Question 14

What does intramembranous ossification form in the maxillary prominence of the 1st arch?

Answer 14

Squamous portions of temporal bone, maxillary bone, zygomatic bone, palatine bone

Question 15

What does intramembranous ossification form in the mandibular prominence of the 1st arch

Answer 15

Mandible

Question 16

What are the muscle components of the 1st pharyngeal arch?

Answer 16

the FOUR muscles of mastication, the Tensor veli palatini (sounds like martini lol) and tensor tympani. Anterior belly of the digastric. Mylohyoid.

Question 17

What is the nerve component of the first pharyngeal arch

Answer 17

Mandibular branch of the TRIGEMINAL (nerve V) nerve supplies the muscles. Sensory supply to skin of face is through opthalmic, maxillary, and mandibular branches of CN V as well

Question 18

What does Reichert’s cartilage of the second arch give rise to?

Answer 18

Stapes, the styloid process, stylohyoid ligament, lesser horn and upper body of hyoid bone

Question 19

What muscles come form the 2nd arch?

Answer 19

Muscles of facial expression, stapedius, stylohyoid, posterior belly of the digastric

Question 20

skeletal component of 3rd pharyngeal arch

Answer 20

Lower part of the BODY and greater horn of the hyoid

Question 21

muscle component of 3rd arch

Answer 21

the ONLY one is the stylopharyngeus

Question 22

Nerve component of 3rd arch

Answer 22

CN IX Glossopharyngeal nerve

Question 23

nerve component of 2nd arch

Answer 23

Facial nerve VII

Question 24

Skeleton of 4th and 6th arches

Answer 24

never as large as other arches, they merge together. They form laryngeal cartilage from lateral plate mesoderm, cartilage does not ossify

Question 25

Muscles of arches 4 and 6

Answer 25

muscles of soft palate, pharynx, intrinsic muscles of larynx, muscles of upper esophagus. Myoblasts of 6th arch become intrinsic laryngeal muscles

Question 26

Nerve component of arch 4 and 6

Answer 26

Vagus Nerve

Question 27

where do pharyngeal arch muscles come from?

Answer 27

from cranial paraxial mesoderm and occipital somites

Question 28

what is the fate of pharyngeal arch arteries

Answer 28

they are modified to form definitive arteries of the upper thorax neck and head

Question 29

What is the diverticulum of pharyngeal pouches

Answer 29

it is a pouch or sace that branches out from a hollow organ.

Question 30

First pouch expands towards

Answer 30

the first pharngeal cleft. The distal portion expands to form the epithelial lining of the tympanic cavity, proximal narrow portions forms teh auditory tube

Question 31

Which pouch forms a stalk like extension?

Answer 31

the first, it eventually becomes the auditory tube

Question 32

Which pouch has epithelial lining that proliferates and forms buds that extend into mesenchyme

Answer 32

The second one does

Question 33

What type of tissue infiltrates the buds of the second pouch?

Answer 33

Lymphatic tissue

Question 34

What does epithelial lining of 2nd pouch become?

Answer 34

the surface epithelium of the palatine tonsil

Question 35

Where does palatine fossa come from?

Answer 35

part of the 2nd pouch

Question 36

what are the 2 regions of the 3rd pouch?

Answer 36

dorsal and ventral

Question 37

What does the dorsal region of 3rd pouch form?

Answer 37

the Inferior parathyroid gland

Question 38

what does the ventral region of the 3rd pouch form?

Answer 38

stroma of the thymus

Question 39

What are the two regions of the 4th pouch?

Answer 39

dorsal and ventral

Question 40

what does dorsal region of 4th pouch form?

Answer 40

glandular cells of superior parathyroid glands

Question 41

what does ventral region of 4th pouch form?

Answer 41

Ultimobranchial body (makes parafollicular cells of thymus) cells are derived from neural crest cells

Question 42

What does the 1st cleft form?

Answer 42

epithelial lining for external auditory meatus

Question 43

Pharyngeal membrane adult remnant is

Answer 43

the tympanic membrane

Question 44

What part of the tonge does arch 1 make?

Answer 44

anterior 2/3

Question 45

when does tongue development begin?

Answer 45

week 4 of development

Question 46

where does second median swelling of the tonge come from?

Answer 46

from the 2nd 3rd and 4th arch

Question 47

what forms the copula?

Answer 47

endoderm and underlying mesenchyme of second arch

Question 48

what forms hypobranchial eminence?

Answer 48

endoderm and underlying mesenchyme of third and fourth arches

Question 49

does the second arch have any contribution to the mucosa of adult tongue?

Answer 49

No the tissue of the 3rd overgrows it

Question 50

what forms the most posterior part of the tonge?

Answer 50

tissue from 3rd and 4th arch endoderm, innervated by CNIX and X

Question 51

where do the anterior and posterior parts of the tonge fuse?

Answer 51

at terminal sulcus

Question 52

where do muscles of tonge come from?

Answer 52

from myotomes of occipital somites that migrate forward to developing tongue, the hypoglossal nerve follows them

Question 53

when does development of the thyroid begin?

Answer 53

day 24

Question 54

what does the thyroid first appear as?

Answer 54

a thickening of endoderm on the floor of the upper pharynx

Question 55

what forms glandular cells of the thyroid?

Answer 55

the thyroid diverticulum

Question 56

what starts forming at the foramen cecum of the developing tongue?

Answer 56

the thyroid gland

Question 57

what is the thyroglossal duct?

Answer 57

the connection the thyroid has to the foramen secum as it grows and descends through the tissue of the neck

Question 58

what happens to the thyroglossal duct?

Answer 58

it degenerates

Question 59

what do follicular cells of thyroid produce?

Answer 59

colloid

Question 60

what to parafollicular cells produce?

Answer 60

calcitonin

Question 61

when does oropharyngeal membrane rupture?

Answer 61

day 26

Question 62

how many facial prominences are there in early development?

Answer 62

five

Question 63

what surrounds the stomodeum?

Answer 63

by frontal prominence cranially, laterally by 1st arch and caudally by cardiac bulge

Question 64

how many primordia of the five come from first arch?

Answer 64

four, the bilateral maxillary prominences and bilateral mandibular prominences

Question 65

What is the fifth prominence?

Answer 65

a single midline structure, it is the single frontonasal prominence, ventral to forebrain, it is the upper border of the stomatodeum

Question 66

What forms the intermaxillary segment?

Answer 66

the merging of the inferior medial nasal prominces

Question 67

what does the intermaxillary segment give rise to?

Answer 67

philtrum of upper lip, upper jaw compoent (where four incisor teeth will form) called premaxillary part of maxilla. And the primary palate

Question 68

When does palate development start?

Answer 68

fifth week

Question 69

Do the posterior parts of the lateral palatine process ossify?

Answer 69

no

Question 70

where does skeletal muscle come from in soft palate?

Answer 70

from myotome cells that have migrated from arches

Question 71

what is the nasopalatine canal? what does it become in an adult?

Answer 71

a small canal that persists between premaxillary part of maxilla and palatine process, it becomes the incisive fossa.

Question 72

Why is the incisive fossa important?

Answer 72

It is considered to be the dividing landmark between anterior and posterior cleft deformitites