Phayngeal Arch

Question 1

When do the pharyngeal arches appear?

Answer 1

In the 4th - 5th week

Question 2

What are the pharyngeal arches separated by externally?

Answer 2

Pharyngeal Clefts / grooves

Question 3

What are the pharyngeal arches separated by internally?

Answer 3

Pouches

Question 4

Which surfaces do ectoderm line?

Answer 4

Outer surfaces of the arches and inner surface of Arch 1

Question 5

Which surfaces are lined by endoderm?

Answer 5

Inner surfaces of all arches except 1

Question 6

What lines the outer surface of the pharyngeal arches?

Answer 6

Ectoderm

Question 7

What lines the inner surface of the pharyngeal arches? Which is the exception?

Answer 7

Endoderm; Arch 1 is lined by ectoderm

Question 8

What does each pharyngeal arch contain?

Answer 8

Nerve
Artery
Cartilage
Muscles

Question 9

What is Arch 1 named?

Answer 9

Mandibular arch

Question 10

Which processes make up Arch 1?

Answer 10

Mandibular process

Maxillary process

Question 11

Which nerve supplies Arch 1?

Answer 11

CN V

Question 12

Which arteries are found in Arch 1?

Answer 12

Maxillary

Carotid

Question 13

Which cartilage is associated with Arch 1?

Answer 13

Meckel’s cartilage

Question 14

Function of cartilage in Arch 1

Answer 14

Provides primitive support

Question 15

What does Meckel’s cartilage form?

Answer 15

bones - incus, malleus

ligaments - sphenomandibular, sphenomalleolar

Question 16

What structures do Arch 1 give rise to?

Answer 16

Body of tongue

Muscles of Mastication - ABD, mylohyoid, temporalis, masseter, pterygoids

Question 17

Which disease is associated with Arch 1? What is it caused by?

Answer 17

Treacher-Collins syndrome - failure of neural crest cell migration

Question 18

What is the name of Arch 2?

Answer 18

Hyoid Arch

Question 19

Which nerve supplies Arch 2?

Answer 19

CN VII

Question 20

What muscles do Arch 2 give?

Answer 20

Muscles of Facial expression + posterior belly of digastric

Question 21

Which cartilage is found in Arch 2?

Answer 21

Reichert’s cartilage

Question 22

What structures do Reichert’s cartilage give?

Answer 22

• stapes
• lesser horn and superior hyoid body
• styloid process, stylohyoid ligament

Question 23

What structures do the 2nd Arch give rise to? x2

Answer 23

Tonsil

Thyroid gland

Question 24

Which nerve supplies the 3rd Arch?

Answer 24

CN IX

Question 25

Which muscle is given by the 3rd Arch

Answer 25

Stylopharyngeus muscle

Question 26

What structures do the 3rd Arch form? x3

Answer 26

Greater horn of hyoid
Inferior hyoid body
Root of the tongue

Question 27

Which nerve supplies the 4th Arch

Answer 27

CN X (Superior laryngeal branch of vagus)

Question 28

Which muscles are given by the 4th Arch?

Answer 28

pharyngeal constrictors

soft palate muscles

Question 29

4th arch cartilage?

Answer 29

Thyroid cartilage

Question 30

Which structures do the 4th Arch give rise to? x2

Answer 30

Pharynx

Epiglottis

Question 31

Which nerves supplies the 6th Arch?

Answer 31

CN X (Recurrent laryngeal branch of vagus)

Question 32

What is the fate of the 5th Arch?

Answer 32

It rapidly disappears

Question 33

What cartilages do the 6th Arch give?

Answer 33

Cricoid and Arytenoid cartilages

Question 34

What does the 1st cleft give? x2

Answer 34

external auditory meatus

ear drum

Question 35

What happens to the 2nd - 6th clefts?

Answer 35

they disappear / are obliterated by the proliferating 2nd arch

Question 36

What does the 1st pouch give? x4

Answer 36

Eustachian tube
Middle ear cavity
Tympanic membrane
VENTRAL PART IS OBLITERATED BY TONGUE

Question 37

What does the 2nd pouch give? x2

Answer 37

Tonsillar fossa
Palatine tonsil
Ventral part - obliterated by tongue

Question 38

What does the 3rd pouch give? x2

Answer 38

Inferior parathyroid gland

Thymus

Question 39

What does the 4th pouch give?

Answer 39

Superior parathyroid gland (will fuse with the inferior one)