Embryology - ENT

Question 1

which germ layer gives rise to the musculature of the face and neck?

Answer 1

mesoderm

Question 2

during which weeks do the pharyngeal arches develop?

Answer 2

weeks 4-5

Question 3

what does each pharyngeal arch consist of?

Answer 3

core of mesenchyme associated with pharyngeal clefts and pouches

neural crest cells

cranial nerve

artery

Question 4

true or false: there are 5 pharyngeal arches and the 5th does not develop in humans

Answer 4

true

only arches 1,2,3,4 and 6 exist

Question 5

which cranial nerve is associated with pharyngeal arch 1?

Answer 5

CN V

Question 6

which cranial nerve is associated with pharyngeal arch 2?

Answer 6

CN VII

Question 7

which cranial nerve is associated with pharyngeal arch 3?

Answer 7

CN IX

Question 8

which cranial nerve is associated with pharyngeal arch 4?

Answer 8

CN X (superior laryngeal branch)

Question 9

which cranial nerve is associated with pharyngeal arch 6?

Answer 9

CN X (recurrent laryngeal branch)

Question 10

what skeletal components are associated with pharyngeal arch 1?

Answer 10

maxillary = maxilla, zygoma, temporal bone 
mandibulary = mandible, meckel's cartilage, incus and malleus

Question 11

what skeletal components are associated with pharyngeal arch 2?

Answer 11

stapes
styloid process of temporal bone
stylohyoid ligament
lesser horn and upper hyoid

Question 12

what skeletal components are associated with pharyngeal arch 3?

Answer 12

greater horn and lower hyoid

Question 13

what skeletal components are associated with pharyngeal arch 4 + 6?

Answer 13

laryngeal cartilages

Question 14

what muscles are associated with pharyngeal arch 1?

Answer 14

muscles of mastication
mylohyoid
tensor tympani
tensor palatini

Question 15

what muscles are associated with pharyngeal arch 2?

Answer 15

muscles of facial expression
stapedius
stylohyoid

Question 16

what muscles are associated with pharyngeal arch 3?

Answer 16

stylopharyngeus

Question 17

what muscles are associated with pharyngeal arch 4?

Answer 17

cricothyroid
levator palatine
pharyngeal constrictors

Question 18

what muscles are associated with pharyngeal arch 6?

Answer 18

intrinsic laryngeal muscles

Question 19

what pharyngeal cleft does the external auditory meatus develop from?

Answer 19

cleft 1

Question 20

what happens to the 2nd-4th pharyngeal clefts?

Answer 20

they usually disappear, lose contact and form the cervical sinus

Question 21

what does the 1st pharyngeal pouch develop into?

Answer 21

middle ear cavity
eustachian tube

ultimately the tympanic membrane

Question 22

what does the 2nd pharyngeal pouch develop into?

Answer 22

palatine tonsil

Question 23

what does the 3rd pharyngeal pouch develop into?

Answer 23

inferior parathyroid gland

thymus

Question 24

what does the 4th pharyngeal pouch develop into?

Answer 24

superior parathyroid gland

ultimobranchial body

Question 25

what are otic placodes?

Answer 25

thickening of the ectoderm at the back of the embryo

Question 26

what are otic vesicles?

Answer 26

endocytosed otic placode that gives rise to the inner ear

Question 27

what three regions develop as part of the otic vesicle?

Answer 27

endolymphatic duct sac utricular portion saccular portion

Question 28

list the five facial swellings present from week 4

Answer 28

frontonasal prominence 2 x maxillary prominences 2 x mandibular prominences

Question 29

what is the stomodeum?

Answer 29

site of the future mouth

Question 30

list the nasal swellings that develop on the frontonasal prominence in week 5

Answer 30

2 x medial nasal swellings | 2 x lateral nasal swellings

Question 31

what grows in the groove between the eye and the lateral nasal swelling?

Answer 31

nasolacrimal duct

Question 32

what nasal features develop from the frontonasal prominence?

Answer 32

bridge | bony septum

Question 33

what nasal features develop from the medial nasal prominence?

Answer 33

crest and tip of nose

Question 34

what nasal features develop from the lateral nasal prominences?

Answer 34

alae (side of nostrils)

Question 35

what does the primary palate form from?

Answer 35

intermaxillary segment formed by the fusion of two medial nasal prominences

Question 36

what does the labial portion of the intermaxillary segment give rise to?

Answer 36

philtrum of upper lip

Question 37

what does the upper jaw component of the intermaxillary segment give rise to?

Answer 37

carries four incisors

Question 38

what does the secondary palate form from?

Answer 38

palatine shelves that grow downwards from maxillary prominences

Question 39

is cleft palate more common in females or males?

Answer 39

females | failure of fusion of secondary palate

Question 40

is cleft lip more common in females or males?

Answer 40

males | failure of fusion of primary palate