Pharyngeal Arches

Question 1

How many pharyngeal arches are there?

Answer 1

1-6, however 5th does not form. So a total of 5

Question 2

How many pharyngeal grooves are there?

Answer 2

4 pairs

Question 3

How many pharyngeal pouches are there?

Answer 3

4 or 5 pairs

Question 4

Which germ layers to the arches contain?

Answer 4

All three:
Ectoderm
Mesoderm
Endoderm

Question 5

What is the primitive mouth that forms between the two regions of the 1st arch, called?

Answer 5

Stomodeum

Question 6

What membrane separates the gut tube from the outside until week 4?

Answer 6

• Oropharyngeal membrane

- later delineated by glossopalatine arch

Question 7

What are the 4 components found in each pharyngeal arch?

Answer 7

1-Aortic arch
2-Cartilaginous rod
3-Muscular component
4-Nerve

Question 8

What do the aortic arches in arches 1 and 2 become?

Answer 8

Largely disappear but some become:

• maxillary,
• external carotid (1)
• stapedial (2)

Question 9

What do the aortic arches in arches 3,4, and 6 become?

Answer 9

Remodel to form

• common and internal carotid (3)
• aortic and subclavian (4)
• pulmonary (6)

Question 10

Which arch gives rise to facial bones?

Answer 10

Arch 1

Question 11

Muscles of mastication come from which arch?

Answer 11

Arch 1

Question 12

Muscles of facial expression come from which arch?

Answer 12

Arch 2

Question 13

Stylopharyngeus muscle comes from which arch?

Answer 13

Arch 3

Question 14

Pharyngeal constrictor muscles come from which arch?

Answer 14

Arch 4

Question 15

Laryngeal muscles come from which arch?

Answer 15

Arch 6

Question 16

Which nerve runs through arch 1?

Answer 16

Cranial nerve V trigeminal (branches into 3, going to pharyngeal prominence, maxillary and mandibular prominences)

Question 17

What nerve runs through arch 2?

Answer 17

Cranial nerve VII facial nerve

Question 18

What nerve runs through arch 3?

Answer 18

Cranial nerve IX Glossopharyngeal

Question 19

Which nerve runs through arches 4 and 6

Answer 19

Cranial nerve X vagus (superior laryngeal to 4th, recurrent laryngeal to 6th)

Question 20

Which muscles come from arch 1?

Answer 20

• All muscles of mastication
• temporallis
• masseter
• medial and lateral pterygoids
• mylohyoid
• tensor palatine
• tensor tympani

Question 21

Which muscles come from arch 2?

Answer 21

• all facial expression muscles
• Posterior belly of digastric
• stylohyoid
• stapedius

Question 22

Which muscles come from arch 4?

Answer 22

• Cricothyroid
• levator palatine
• constrictors of pharynx

Question 23

What skeletal elements come from arch 1?

Answer 23

Merkels cartilage
Maxilla
Mandible
Malleus
Incus

Question 24

What skeletal elements come from arch 2?

Answer 24

Stapes
Styloid process
Lesser horn and upper portion of body of hyoid bone

Question 25

What skeletal elements come from arch 3?

Answer 25

Greater horn and lower portion of body of hyoid bone

Question 26

Pharyngeal clefts are found where?

Answer 26

Exterior between arches

Question 27

Where are pouches found?

Answer 27

Internally between arches

Question 28

Which is the only cleft that is not obliterated?

Answer 28

Cleft 1

Question 29

What does cleft 1 become?

Answer 29

External auditory meatus

Question 30

What does the first pharyngeal pouch become?

Answer 30

Distally -Tympanic membrane | proximally -auditory tube

Question 31

What does the secondary pharyngeal pouch become?

Answer 31

Lining of the crypts of the palatine tonsil

Question 32

What does the third pharyngeal pouch give rise to?

Answer 32

Dorsal wing- Inferior Parathyroid | Ventral wing-thymus

Question 33

What does the fourth pharyngeal pouch give rise to?

Answer 33

Dorsal wing-superior parathyroid | Ventral wing-ultimobranchial body

Question 34

What are the two pharyngeal membranes and which one breaks down?

Answer 34

- oropharyngeal(breaks down at week 4) | - tympanic membrane

Question 35

Pharyngeal arches may also be referred to as?

Answer 35

Branchial arches