Pharyngeal arches

Question 1

cysts

Answer 1

sealed cavity filled with air, pus, fluid

Question 2

sinus

Answer 2

cavity within a tissue, can open externally

Question 3

fistula

Answer 3

abnormal connection between 2 structures

Question 4

migration

Answer 4

cells move (or don’t) during development

Question 5

Proliferation

Answer 5

growth in cell number thru cell division

Question 6

Genetics

Answer 6

mutations change patterns in migration, proliferation, etc..

Question 7

how many pharyngeal arches are there?

Answer 7

5

Question 8

when do pharyngeal arches emerge?

Answer 8

at neural tube closure

about 4 weeks of development

Question 9

what is unique about the first arch

Answer 9

shows two prominences

• maxillary prominence
• mandibular promnence

Question 10

what are the components found in each arch?

Answer 10

nerve, artery, cartilage, and muscular component

Question 11

aortic arches

Answer 11

arise from mesoderm and bridge between the truncus arteriosus and the dorsal aorta

Question 12

aortic arch 1

Answer 12

maxillary and external carotid

Question 13

aortic arch 2

Answer 13

stapedial

Question 14

aortic arch 3

Answer 14

common and internal carotid

Question 15

aortic arch 4

Answer 15

aortic and subclavian

Question 16

aortic arch 6

Answer 16

pulmonary

Question 17

cartilage arch 1

Answer 17

meckel’s cartilage, maxilla, mandible, malleus, incus

Question 18

cartilage arch 2

Answer 18

stapes, styloid process, lesser horn and upper portion of body of hyoid bone

Question 19

cartilage arch 3

Answer 19

greater horn and lower portion of body of hyoid bone

Question 20

cartilage arch 4-6

Answer 20

laryngeal cartilages

Question 21

muscles arch 1

Answer 21

muscles of mastication

eg: temporalis, masseter, medial and lateral pterygoids

Question 22

muscles arch 2

Answer 22

all muscles of facial expression

Question 23

muscles arch 3

Answer 23

stylopharyngeus

Question 24

muscles arch 4

Answer 24

constrictors of pharynx

Question 25

muscles arch 6

Answer 25

intrinsic muscles of larynx

Question 26

nerves of arch 1

Answer 26

trigeminal

Question 27

nerves of arch 2

Answer 27

facial nerve

Question 28

nerves of arch 3

Answer 28

glossopharyngeal (IX)

Question 29

nerves of arch 4

Answer 29

vagus superior laryngeal

Question 30

nerves of arch 6

Answer 30

recurrent laryngeal

Question 31

mandibular process of arch 1 forms:

Answer 31

lower lip, lower face, lower cheek regions, chin, mandible, body of the tongue

Question 32

maxillary process of arch 1 forms:

Answer 32

midface, upper cheek regions, upper lip sides, secondary palate, maxilla, and zygomatic bone

Question 33

treacher collins syndrome mutation

Answer 33

Treachle gene mutation | 1st arch syndrome

Question 34

Pierre Robin sequence

Answer 34

hypoplasia of mandible, misplacement of tongue, cleft palate, defects of eye and ear, airway obstruction *cause is unknown

Question 35

How many pharyngeal grooves are there?

Answer 35

4

Question 36

pharyngeal grooves/clefts are made of what origin?

Answer 36

ectoderm

Question 37

which cleft is the only cleft not obliterated in development?

Answer 37

the 1st one

Question 38

what does the 1st cleft give rise to?

Answer 38

the external auditory meatus

Question 39

Preauricular sinus and cysts

Answer 39

often unilateral 1st or 2nd arch defect

Question 40

Branchial sinuses, cysts, and fistulas | Lateral cervical

Answer 40

uncommon, open to external(to neck), failure of second groove or cervical sinus to obliterate *if it is continuous with skin of neck it is a fistula

Question 41

Branchial sinuses, cysts, and fistulas | Internal branchial

Answer 41

rare, persistent second pouch, open into intratonsillar cleft (into pharynx) 2nd pouch defect

Question 42

how many pharyngeal pouches do you have?

Answer 42

4 or 5 pairs

Question 43

pouches are of what origin?

Answer 43

endodermal origin

Question 44

1st pharyngeal pouch gives to what structure?

Answer 44

distal portion- forms middle ear and makes the inner portion of tympanic membrane proximal: forms eustachian tube

Question 45

second pharyngeal pouch gives to what structure?

Answer 45

the lining of the crypts in the palatine tonsils and tonsillar fossa

Question 46

third pharyngeal pouch gives rise to what?

Answer 46

inferior parathyroid gland(dorsal wing) and the thymus(ventral wing)

Question 47

Fourth pharyngeal pouch gives rise to what?

Answer 47

superior parathyroid gland(dorsal) and the ultimobranchial body aka C cells of thyroid (ventral wing)

Question 48

migration defects: | cervical thymus

Answer 48

cord of thymus persists in neck on path of descent

Question 49

migration defects: | accessory thymus

Answer 49

piece of thymus remaining in path of descent

Question 50

DiGeorge syndrome

Answer 50

failure of 3rd and 4th pouches to differentiate into thymus, parathyroid -neural crest defects

Question 51

DiGeorge syndrome CATCH 22

Answer 51

``` C: cardiac abnormality (tetralogy of Fallot) A: abnormal faces T: thymic aplasia C: cleft palate H: hypocalcemia/hypoparathyroidism ```

Question 52

tetralogy of Fallot

Answer 52

overriding aorta pulmonic stenosis ventricular septal defect right ventricular hypertrophy

Question 53

Hox genes regulate what?

Answer 53

anterior to posterior identity | up and down rostral to caudal

Question 54

T/F neural crest cells, with different anterior to posterior identities as determined by Hox expression, migrate form the Rhombomeres into the pharyngeal arches

Answer 54

true

Question 55

Loss of Hox expression causes arch 2 to do what?

Answer 55

lose it anterior to posterior identity and gives a duplicate arch 1 structure -so no lesser horn or upper body of hyoid, but will have two malleus, incus, and tympanic ring

Question 56

what does the Dlx code

Answer 56

proximal - distal or ventral -dorsal of the arches

Question 57

development of the tongue (floor of the arches)

Answer 57

arch 1 forms anterior 2/3 epithelium arch 2 is covered up as arch 3 grows arch 3 forms most of posterior 1/3 epithelium arch 4 forms the bit of tongue at very back of throat

Question 58

arch 1 in tongue formation

Answer 58

median tongue bud distal tongue buds -these become anterior 2/3 of tongue

Question 59

arch 2 in tongue formation

Answer 59

forms middle swelling called copula

Question 60

arches 3 and 4 in tongue formation

Answer 60

- hypopharyngeal eminence over grows copula(arch 2) and gives rise to posterior 1/3 * epiglottis arises posterior to hypopharyngeal eminence

Question 61

where do tongue muscles come from?

Answer 61

occipital somites

Question 62

what is the dividing line between oral tongue and pharyngeal tongue

Answer 62

terminal sulcus groove

Question 63

what is the foramen cecum

Answer 63

at the midline and is the site of thyroid primordium

Question 64

thyroid gland developement

Answer 64

forms from an endodermal diverticulum(pouch) just posterior to the floor of the 1st arch **this not a pharyngeal pouch!! not bilateral -diverticulum elongates into the thyroglossal duct.

Question 65

development of the pituitary gland

Answer 65

forms from the upward invagination of the oral ectoderm in the stomodeum (Rathke's pouch) -separates from oral epithelium, moves into contact with diencephalon.

Question 66

neurohypophysis(posterior pituitary)

Answer 66

develops from the developing brain (neural ectoderm)

Question 67

adenohypophysis (anterior pituitary)

Answer 67

develops from the stomodeum roof (oral ectoderm).