Embryology

Question 1

Aortic arch 1 contributes to

Answer 1

maxillary a.

“First is Max”

Question 2

Aortic arch 2 forms part of

Answer 2

the hyoid and stapedial a.

“Second is Stapedial”

Question 3

Aortic arch 3 forms the

Answer 3

common carotid a. and proximal portion of the internal carotid a. (C is the 3rd letter)

Question 4

Aortic arch 4 forms the

Answer 4

Right proximal subclavian a. and part of the aortic arch

“fouRS”

Question 5

Aortic arch 5

Answer 5

degenerates during early development

Question 6

Aortic arch 6

Answer 6

Pulmonary arteries and ductus arteriosis

Question 7

How many pairs of pharyngeal arches are there?

Answer 7

5 (1, 2, 3, 4, 6). 4 and 6 are kind of fused

Question 8

The pharyngeal arches are seperated by?

Answer 8

Pharyngeal grooves

Question 9

What are the outter, middle, and inner layers of the pharngeal arches composed of?

Answer 9

outter - ectoderm
middle - mesenchyme
inside - endoderm

Question 10

What does the neurocest cells of pharyngeal arch 1 become?

Answer 10

The maxillary prominence -> maxillary bone, zygomatic, & squamous portions of temporal bone
Mandibular prominence -> mandible, malleus, incus
Think Trigem structures

Question 11

Innervation of pharyngeal arch 1 is?

Answer 11

Trigeminal (V)

Question 12

Innervation of pharyngeal arch 2 is?

Answer 12

Facial (VII)

Question 13

Innervation of pharyngeal arch 3 is?

Answer 13

Glossopharyngeal (IX)

Question 14

Innervation of pharyngeal arch 4-6 is?

Answer 14

Vagus (X)

Question 15

What does the neurocest cells of pharyngeal arch 2 gives rise to?

Answer 15

Lesser cornu of hyoid, stylohyoid ligament, stylohyoid process, stapes
Think Facial n.

Question 16

What does the neurocest cells of pharyngeal arch 3 gives rise to?

Answer 16

Greater cornu of hyoid

3 is the smallest, think glossopharyngeal n.

Question 17

What does the neurocest cells of paryngeal arch 4 gives rise to?

Answer 17

Laryngeal cartilages

Think Vagus

Question 18

What does the mesoderm of pharyngeal arch 1 give rise to?

Answer 18

Muscles of mastication (temporalis, masseter, mylohyoid, ant belly of digastric, tensor tympani)

Question 19

What does the mesoderm of pharyngeal arch 2 give rise to?

Answer 19

Muscles of facial expression

Stylohyoid, pos digastric

Question 20

What does the mesoderm of pharyngeal arch 3 give rise to?

Answer 20

Stylopharyngeus

Question 21

What does the mesoderm of pharyngeal arch 4/6 give rise to?

Answer 21

Pharyngeal constrictors, soft palate, laryngeal muscles

Question 22

neural crest cells give rise to?

Answer 22

Bone and cartilage

Question 23

Mesoderm gives rise to?

Answer 23

Muscles

Question 24

The pharyngeal endoderm becomes the?

Answer 24

Pharyngeal pouches

Question 25

Pharyngeal pouch 1 becomes the?

Answer 25

tubotympanic recess -> tympanic cavity, mastoid antrum, auditory tube

Question 26

Pharyngeal pouch 2 becomes the?

Answer 26

Palatine tonsilar bed -> induces lymphoid tissue invasion and together form the palatine tonsil

Question 27

Pharyngeal pouch 3 becomes the?

Answer 27

Thymus | inferior parathyroid

Question 28

Pharyngeal pouch 4/6 becomes the?

Answer 28

superior parathyroid

Question 29

Pharyngeal groove 1 becomes the?

Answer 29

External acoustic meatus

Question 30

Pharyngeal grooves 2-4 become the?

Answer 30

Cervical sinus -> cervical vesicle | Both degenerate over time, persistance causes and branchial cyst/sinus/fistula

Question 31

Describe the development of the thyroid

Answer 31

Endoderm between pharyngeal arch 1 and 2 -> thyroid primoridum -> descends below the hyoid. Mature glad is anterior to trachea, caudal to larynx

Question 32

The face is formed from what 3 structures?

Answer 32

Frontonasal prominence Paired maxillary prominence Paired mandibular promninence

Question 33

As the maxillary prominence grow they

Answer 33

push the nasal prominences toward the midline of the face

Question 34

The medial nasal prominences fuse and give rise to

Answer 34

Bridge of the nose | Intermaxillary segment

Question 35

When the maxillary prominence fuses with the intermaxillary segement it forms

Answer 35

the Smooth upper lip | Fusion of primary and secondary palate

Question 36

The lateral nasal prominences fuse with the maxillary prominence and form the

Answer 36

alae of the nose and the nasolacrimal duct forms at the site of fusion

Question 37

The two nasal sacs fuse in the midline to form

Answer 37

A single nasal cavity with a thin membrane that ruptures to create a continuous nasal and oral cavity

Question 38

What forms to separate the oral and nasal cavities?

Answer 38

the secondary palate is formed. Prevents aspiration of food

Question 39

The primary palate is derived from

Answer 39

the intermaxillary segment

Question 40

The secondary palate is derived from

Answer 40

fusion of the palatine shelves on the maxillary prominence (source of cleft lips)

Question 41

A portion of the neural tube is transiently divided into segments termed

Answer 41

Rhombomeres

Question 42

How many pharyngeal clefts are present once the final number of pharyngeal arches has been established?

Answer 42

1

Question 43

The taste buds in the anterior 2/3rds of the tongue are innervated by

Answer 43

Facial n.

Question 44

Olfactory sensory neurons arise from

Answer 44

nasal placodes within the nasal pits

Question 45

What are the parts of the middle ear?

Answer 45

incus, stapes, malleous, round window niche

Question 46

The tensory tympani and mylohyoid arise from which arch?

Answer 46

1st

Question 47

The stylohyoid arises from which arch?

Answer 47

2nd

Question 48

The lateral cricoarytenoid arise from which arch?

Answer 48

4th