Pharyngeal Arches

Question 1

When does the head and neck start to develop?

Answer 1

Week 4

Question 2

What forms the structure of the head and neck?

Answer 2

Pharyngeal arches

Question 3

How do the pharyngeal arches form?

Answer 3

Growth of mesenchymal tissue in cranial region forms arches separated by clefts

Question 4

What separates the arches on the internal surface?

Answer 4

Pharyngeal pouches

Question 5

What separates the arches on the external surface?

Answer 5

Pharyngeal clefts

Question 6

What makes up the internal surface?

Answer 6

Endoderm

Question 7

What makes up the external surface?

Answer 7

Ectoderm

Question 8

How many pharyngeal clefts are there initially?

Answer 8

4

Question 9

What happens to the clefts?

Answer 9

1st cleft becomes external auditory meatus

2nd, 3rd, 4th are obliterated by 2nd pharyngeal arch

Question 10

How many pharyngeal arches are there initially?

Answer 10

6

Question 11

Which pharyngeal arch regresses?

Answer 11

5th

Question 12

What makes up each arch?

Answer 12

Cranial nerve
Muscular component
Skeletal/cartilaginous supporting element
Vascular component

Question 13

How is the 1st arch split?

Answer 13

Maxillary prominence (dorsal portion)

Mandibular prominence (ventral portion)

Question 14

What does the maxillary prominence form?

Answer 14

Maxilla
Zygomatic bone
Part of temporal bone

Question 15

What cartilage is associated with the maxillary prominence?

Answer 15

Maxillary cartilage

Question 16

What does the maxillary cartilage give rise to?

Answer 16

Incus

Question 17

What does the mandibular prominence form?

Answer 17

Mandible

Question 18

What cartilage is associated with the mandibular prominence?

Answer 18

Meckel’s cartilage

Question 19

What does Meckel’s cartilage give rise to?

Answer 19

Malleus

Sphenomandibular ligament

Question 20

What is the artery of the 1st arch?

Answer 20

Maxillary artery

Question 21

What cranial nerve is associated with the 1st arch?

Answer 21

CN V - trigeminal

Question 22

What muscles are formed by the 1st arch?

Answer 22

Muscles of mastication
Mylohyid
Anterior belly of digastric
Tensor tympani

Question 23

What are the arteries of the 2nd arch?

Answer 23

Stapedial artery

Hyoid artery

Question 24

What is the cartilage component of the 2nd arch?

Answer 24

Reichart’s cartilage

Question 25

What does Reichart's cartilage give rise to?

Answer 25

Stapes Styloid process Stylohyoid ligament Part of hyoid bone

Question 26

What cranial nerve is associated with the 2nd arch?

Answer 26

CN VII - facial

Question 27

What muscles are formed by the 2nd arch?

Answer 27

``` Muscles of facial expression Stapedius Stylohyoid Platysma Posterior belly of digastric ```

Question 28

What is the artery of the 3rd arch?

Answer 28

Common carotid

Question 29

What does the cartilage of the 3rd arch give rise to?

Answer 29

Part of hyoid

Question 30

What cranial nerve is associated with the 3rd arch?

Answer 30

CN IX - glossopharyngeal

Question 31

What muscle is formed by the 3rd arch?

Answer 31

Stylopharyngeus

Question 32

What are the arteries of the 4th arch?

Answer 32

Right = proximal subclavian Left = aortic arch

Question 33

What does the cartilage of the 4th arch give rise to?

Answer 33

Laryngeal cartilages - thyroid - corniculate - cuneiform

Question 34

What cranial nerve is associated with the 4th arch?

Answer 34

Superior laryngeal branch of CN X - vagus

Question 35

What muscles are formed by the 4th arch?

Answer 35

Pharyngeal constrictors Levator palatini Cricothyroid

Question 36

What are the arteries of the 6th arch?

Answer 36

Right - proximal pulmonary arteries Left - ductus arteriosus

Question 37

What cranial nerve is associated the 6th arch?

Answer 37

Recurrent laryngeal branch of CN X - vagus

Question 38

How many pharyngeal pouches are there?

Answer 38

5 - only 4 give rise to adult structures

Question 39

What is formed from the 1st pouch?

Answer 39

Eustachian tube | Middle ear cavity

Question 40

What is formed from the 2nd pouch?

Answer 40

Lining of the palatine tonsils

Question 41

What is formed from the 3rd pouch?

Answer 41

Dorsal - inferior parathyroid glands Ventral - thymus

Question 42

What is formed from the 4th pouch?

Answer 42

Dorsal - superior parathyroid glands