Session 2 - Part II

Question 1

What forms the embryonic head and neck?

Answer 1

The pharyngeal arches

Question 2

What drives the development of the face?

Answer 2

The nose

Question 3

What are pharyngeal arches?

Answer 3

System mesenchymal proliferations in the neck region of the embryo
Have a mesenchyme core, ectoderm covering (pharyngeal arch), endoderm inner side (pharyngeal cleft)

Question 4

How many pharyngeal arches are there?

Answer 4

5

1 –> 6, but 5 regresses in humans

Question 5

What is the largest pharyngeal arch?

Answer 5

1st

Question 6

What is the smallest pharyngeal arch?

Answer 6

6th

Question 7

Which section of the neural tube forms the brain?

Answer 7

The anterior end

Question 8

What are 3 stages of neural tube making the brain?

Answer 8

Prosencephalon –> Forebrain
Mesencephalon –> Midbrain
Rhambencephalon –> Hindbrain

Question 9

How many cranial nerves develop?

Answer 9

12

Question 10

Which cranial nerves are derived from the mid/hind brain?

Answer 10

All except for nerve I & II

Question 11

Which cranial nerves supply the pharyngeal arches and the derivatives of them?

Answer 11

V, VII, IX, X

Question 12

What nerve does CN XI become?

Answer 12

Cranial accessory nerve

Question 13

What nerve does CN XII become?

Answer 13

Hypoglossal nerve

Question 14

What is the facial skeleton derived from?

Answer 14

Frontonasal prominence and 1st pharyngeal arch

Question 15

What are the muscles of mastication derived from?

Answer 15

Pharyngeal arch I

Question 16

What are the muscles of facial expression derived from?

Answer 16

Pharyngeal arch II

Question 17

What does the 3rd pharyngeal arch become?

Answer 17

Stylopharyngeus muscle

Question 18

What does the 4th pharyngeal arch become?

Answer 18

Cricothyroid
Levator palantini
Pharynx constrictors

Question 19

What does the 6th pharyngeal arch become?

Answer 19

Intrinsic muscles of the larynx

Question 20

What is the nerve of the first pharyngeal arch?

Answer 20

CN V

Question 21

What does CN V become?

Answer 21

Trigeminal nerve

Question 22

What is the function of the Trigeminal nerve?

Answer 22

Sensory nerve of the head, skin of the face and lining of the mouth & nose
Motor nerve of the muscles of mastication and muscles derived from the mandibular process

Question 23

What is the nerve of the 2nd pharyngeal arch?

Answer 23

CN VII

Question 24

What does CN VII become?

Answer 24

Facial nerve

Question 25

What is the function of the Facial nerve?

Answer 25

Sensory of taste buds in the anterior 2/3rd of tongue | Motor of muscles facial expression and those derived from 2nd pharyngeal arch

Question 26

What does the Facial nerve pass through?

Answer 26

Stylomastoid foramen | Parotid gland

Question 27

What is the nerve of the 3rd pharyngeal arch?

Answer 27

CN IX

Question 28

What does CN IX become?

Answer 28

Glossopharyngeal nerve

Question 29

What is the function of the Glossopharyngeal nerve?

Answer 29

Innervates stylopharyngeus muscle | General & specific sensory innervation to posterior 1/3 of tongue

Question 30

What is the nerve of the 4th & 6th pharyngeal arch?

Answer 30

CN X

Question 31

What does CN X become?

Answer 31

Vagus nerve

Question 32

What is the branch of the Vagus nerve for the 4th pharyngeal arch?

Answer 32

Superior laryngeal nerve

Question 33

What is the function of the Superior laryngeal nerve?

Answer 33

Innervates the Cricothyroid which constricts the pharynx

Question 34

What is the branch of the Vagus nerve for the 6th pharyngeal arch?

Answer 34

Recurrent laryngeal nerve

Question 35

What is the function of the Recurrent laryngeal nerve?

Answer 35

Intrinsic muscles of the larynx

Question 36

What is unique about the Recurrent laryngeal nerve?

Answer 36

It wraps around the arch of the Aorta

Question 37

What does each pharyngeal arch develop?

Answer 37

A neural crest derived cartilage bar (Contributes to basic skeletal parts)

Question 38

What does the 1st cartilage bar do? (Meckel's cartilage)

Answer 38

Divides into Maxillary and Mandibular prominences

Question 39

What does the Mandicular prominence of the 1st cartilage bar do?

Answer 39

Provides a template for the mandible which forms via membranous ossification leaving outline for the bone to form (Cartilage doesn't go to bone)

Question 40

What does the 2nd cartilage bar do? (Reichert's cartilage)

Answer 40

Contributes to middle ear development (Stapes) | Contributes to styloid process, Hyoid bone (remainder from 3rd arch)

Question 41

What does the 4th & 6th arch mesenchyme become?

Answer 41

The pharyngeal floor (Aortic sac lies in floor of pharynx) | Thyroid, Arytenoid, Cricoid (Derived from their cartilage bar)

Question 42

What does the 1st & 2nd Aortic arch become?

Answer 42

They regress

Question 43

What does the 3rd Aortic arch become?

Answer 43

Internal carotid artery

Question 44

What does the 4th Aortic arch become?

Answer 44

``` Arch of the Aorta (Left) Brachiocephalic artery (Right) ```

Question 45

What does the 6th Aortic arch become?

Answer 45

Pulmonary arch

Question 46

What do the pharyngeal pouches mainly become?

Answer 46

Glandular tissue

Question 47

How is the Parathyroid gland formed?

Answer 47

From the dorsal portion of the 3rd & 4th pharyngeal pouches

Question 48

How is the Thymus gland formed?

Answer 48

From the ventral portion of the 3rd & 4th pharyngeal pouches | It is formed as 2 lobes that join in the middle

Question 49

Which pharyngeal pouch forms the middle ear?

Answer 49

1st Ossicles = cartiage bar derivative Tympanic cavity & auditory tube = pouch derivative

Question 50

What can cause a middle ear infection in children?

Answer 50

Pharynx infection

Question 51

What happens to the pharyngeal clefts?

Answer 51

The 2nd grows down and covers all leaving only the 1st remaining

Question 52

What can occur if the cervical sinus is not obliterated by the 2nd cleft?

Answer 52

Cysts/Fistulae can occur anywhere along the anterior border of the SCM

Question 53

What is a difference between a cyst and fistulae?

Answer 53

A fistulae is a cyst with an opening to the surface

Question 54

Which pouch has lymphoid precursors occupying it?

Answer 54

2nd | Makes tonsils