ENT embryology

Question 1

wks gestation that pharyngeal arches develop at

Answer 1

4-5

Question 2

1st pharyngeal arch develops at day

Answer 2

22

Question 3

2nd and 3rd pharyngeal arch develop at day

Answer 3

24

Question 4

4th + 6th pharyngeal arch develops at day

Answer 4

29

Question 5

pharyngeal arches consist of:
a core of \_\_\_ => \_\_\_
and \_\_\_ which => \_\_\_
a \_\_ component
\_\_\_ arches

Answer 5

mesenchyme (from paraxial and lateral plate mesoderm) => face and neck muscles
neural crest cells => skeletal face
CN
aortic

Question 6

externally pharyngeal arches are separated by __ = __ lining

Answer 6

deep pharyngeal clefts

ectoderm lining

Question 7

internally pharyngeal arches are separated by ___ = ___ lining

Answer 7

pharyngeal pouches

endoderm

Question 8

neural crest cells migrate __ to __ into pharyngeal arches and lay pathway for __

Answer 8

dorsal to ventral

CNs

Question 9

nerves associated with 1st pharyngeal arch

Answer 9

CN V2+3

Question 10

nerves associated with 2nd pharyngeal arch

Answer 10

CN VII

Question 11

nerves associated with 3rd pharyngeal arch

Answer 11

CNIX

Question 12

4th pharyngeal arch is associated with which nerve

Answer 12

superior laryngeal of CN X

Question 13

6th pharyngeal arch is associated with which nerve

Answer 13

recurrent laryngeal of CN X

Question 14

skeletal components of the head that are derived from the 1st pharyngeal arch

Answer 14

maxillay process (dorsal portion) - maxilla, zygoma, part of temporal bone
mandibular process (ventral) - meckel's cartilage (regresses) then incus, malleus and mandible

Question 15

muscles derived from the 1st pharyngeal arch

Answer 15

mastication muscles
mylohyoid
anterior belly of the digastric
tensor tympani
tensor palatini (CNV3)

Question 16

sensory supply of the face derived from 1st pharyngeal arch comes from CN__s

Answer 16

V1+2+3

Question 17

skeletal parts of head that are derived from 2nd pharyngeal arch

Answer 17

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

Question 18

muscles derived from the 2nd pharyngeal arch

Answer 18

muscles of facial expression
stapedius
stylohyoid
posterior belly of digastric
auricular muscles (tend to regress

Question 19

skeletal parts of head derived from 3rd pharyngeal arch =

Answer 19

greater horn and lower part of body of hyoid

Question 20

muscles derived from 3rd pharyngeal arch

Answer 20

stylopharyngeus

Question 21

the laryngeal cartilages are derived from __ (pharyngeal arches)

Answer 21

4th and 6th

Question 22

muscles derived from the 4th pharyngeal arch

Answer 22

cricothyroid
levator palatini
pharyngeal constrictors

Question 23

muscles derived from the 6th pharyngeal arch

Answer 23

intrinsic laryngeal

Question 24

the external auditory meatus is derived embryologically from

Answer 24

the 1st pharyngeal cleft

Question 25

2nd - 4th pharyngeal clefts merge to form the __ which later regresses (if persists can => ___)

Answer 25

cervical sinus | cyst

Question 26

the first pharyngeal pouch goes on to form __+__+__

Answer 26

middle ear, eustachian tube and tympanic membrane

Question 27

the 2nd pharyngeal pouch goes on to form ___

Answer 27

palatine tonsil

Question 28

the 3rd pharyngeal pouch goes on to form ___+__

Answer 28

inferior PT gland (dorsally) and thymus (ventrally)

Question 29

the 4th pharyngeal pouch goes on to form __+__

Answer 29

superior PT gland, ultimobrachial body (C cells of thyroid)

Question 30

otic placodes = thickenings of ___ | they overlie the ____ and => ___=>___

Answer 30

ectoderm hindbrain otic vesicles and then inner ear

Question 31

utricular portion of the otic vesicles goes on to form the

Answer 31

semicircular canals

Question 32

the saccular portion of the otic vesicles goes on to form the

Answer 32

cochlea

Question 33

3 dilated ends of the semicircular canals =

Answer 33

crus ampullare

Question 34

there are __ crus non-ampullare in the semicircular canals and these are ___ (description)

Answer 34

2 | non-dilated

Question 35

within the ampullae of the semicircular canals there is the crista ampullaris =

Answer 35

sensory cells for balance and vestibular fibres of VIII

Question 36

the cochlea has ___ spirals

Answer 36

2.5

Question 37

the ridge of bone in the cochlea =

Answer 37

modiolus

Question 38

the membrane in the organ of corti =

Answer 38

tectorial membrane

Question 39

in cochlea: | ___ then vestibular membrane then ____ then basilar membrane then __

Answer 39

scala vestibuli scala media/cochlear duct scala tympani

Question 40

external auditory meatus embryology: | in month 3 epithelial cells proliferate to form ___ => dissolves at ___ and contributes to ___

Answer 40

meatal plug month 7 eardrum

Question 41

auricle = 6 ___ around the ___

Answer 41

``` mesenchymal proliferations (3 from 1st arch and 3 from 2nd arch) 1st pharyngeal cleft ```

Question 42

embryology: | ____ fuse to form the auricle

Answer 42

auricular hillocks

Question 43

5 facial swellings present at wk 4 gestation

Answer 43

frontonasal prominence 2 maxillary prominences 2 mandibular prominences

Question 44

at wk 5 gestation 4 more nasal swellings (__+__) develop due to ____

Answer 44

2x medial 2x lateral nasal swellings invagination of nasal placodes and surroundings swell around them

Question 45

at wk 6 ___ move down to meet ___ these fuse to leave the ___ between maxillary prominence and lateral nasal prominence

Answer 45

nasal swellings maxillary prominence nasolacrimal groove

Question 46

embryological derivatives of upper lip =

Answer 46

2x medial nasal swellings | 2x maxillary prominences

Question 47

embryological derivatives of lower lip

Answer 47

mandibular prominence

Question 48

frontonasal prominence (embryological) goes on to form

Answer 48

bridge and septum of nose

Question 49

medial nasal prominences go on to form

Answer 49

crest and tip of nose

Question 50

alae are embryologically derived from

Answer 50

lateral nasal swellings

Question 51

cleft palate and lips are more common M/F

Answer 51

``` palate = F>M lips = M>F ```

Question 52

anterior cleft lip lies anterior to __

Answer 52

incisive foramen

Question 53

nasal cavity junction with pharynx contains the

Answer 53

choanae