Lecture 1 - Primordia

Question 1

Placodes

Answer 1

Ectodermal thickenings that form structures for special senses

Question 2

Somites

Answer 2

Masses of mesoderm that form skeletal muscles

• preotic somites = eye muscles
• postotic somites = tongue muscles

Question 3

pharyngeal/branchial arches

Answer 3

masses of tissue that flank the developing gut

• outer lining = ectoderm
• inner lining = endoderm except for banchial arch 1

Question 4

branchial arch derivatives

Answer 4

bone or cartilage
skeletal muscle
skin from overlying ectoderm (sensory input)
area of gut from endodermal lining

Question 5

pharyngeal clefts

Answer 5

ectodermal surface that usually smooths out

cleft 1 = ear hole (ext. auditory meatus)

Question 6

pharyngeal pouches

Answer 6

endodermal surface

1. tympanic membrane, middle ear cavity, auditory/eustachian tube
2. palatine tonsil
3. inferior parathyroid glands, thymus
4. superior parathyroid glands
5. C cells of thyroid gland

Question 7

cranial nerve 1

Answer 7

olfactory
olfactory placode
sensory only

Question 8

cranial nerve 2

Answer 8

optic
optic placode
sensory only

Question 9

cranial nerve 3

Answer 9

oculomotore
preotic somite
motor only

Question 10

cranial nerve 4

Answer 10

trochlear
preotic somite
motor only

Question 11

cranial nerve 5

Answer 11

trigeminal
branchial arch 1
both

Question 12

cranial nerve 6

Answer 12

abducens
preotic somite
motor only

Question 13

cranial nerve 7

Answer 13

facial
branchial arch 2
both

Question 14

cranial nerve 8

Answer 14

vestibulocochlear
otic placode
sensory only

Question 15

cranial nerve 9

Answer 15

glossopharyngeal
branchial arch 3
both

Question 16

cranial nerve 10

Answer 16

vagus
branchial arch 4 and 6
both

Question 17

cranial nerve 11

Answer 17

accessory
?? - thought to be from branchial arch 5
motor only

Question 18

cranial nerve 12

Answer 18

hypoglossal
postotic somites
motor only

Question 19

components in cranial nerves

Answer 19

general somatosensory
special somatosensory
special and general viscerosensory
visceromotor/parasympathetic 
branchiomotor
somatomotor

Question 20

V1

Answer 20

trigeminal sensory
ophthalmic nerve (forehead)
goes through supraorbital foramen
supraorbital nerve

Question 21

V2

Answer 21

trigeminal sensory
maxillary nerve (cheek, upper jaw)
goes through infraorbital foramen
infraorbital nerve

Question 22

V3

Answer 22

trigeminal sensory
mandibular nerve (lower jaw)
goes through mental foramen
mental nerve

Question 23

muscles of facial expression

Answer 23

from branchial arch 2 (Facial VII)
insert into the skin 
produce facial expression + protective 
temporal
zygomatic 
buccal
marginal mandibular 
cervical