1.2 Development of the Head and Neck Flashcards Preview

Semester 4- Head and Neck > 1.2 Development of the Head and Neck > Flashcards

Flashcards in 1.2 Development of the Head and Neck Deck (38):
1

What are the pharyngeal archs?

A system of mesenchymal proliferations in the neck region of the embryo

2

How many arches develop and how many are in the adult?

1-6 develop, number 5 regresses, so 5 are left in the adult

3

What structures are associated with each arch?

Artery, nerve, vein and cartilage bar

4

What is a pharyngeal arch made up of?

Mesoderm core with 1 half surrounded by ectoderm and 1 half surrounded by endoderm

5

How does the neural tube develop?

The notochord signals the overlying ectoderm to thicken. The edges elevate and curl in to form a tube.

6

Name the 3 vesicles the anterior end of the neural tube turns into

Prosencephalon= forebrain
Mesencephalon= midbrain
Rhombencephalon= hindbrain

7

Describe the formation of pharyngeal clefts and pouches

As the embryo grows, clefts appear between the arches. The arches are then engulfed by the growing embryo and so are inside the body. They are then referred to as pharyngeal pouches.

8

Which areas of the brain do CNIII- XII develop from?

Midbrain and hindbrain

9

Which nerves are the 'nerves of the pharyngeal arches'?

CN V, VII, IX and X

10

What type of fibres do the nerves of the pharyngeal arches have and what do they innervate?

Both sensory and motor functions
They innervate the derivatives of the pharyngeal arches

11

Where is the facial skeleton derived from?

Frontonasal prominence
1st pharyngeal arch

12

Where are the muscles of mastication derived from?

1st pharyngeal arch

13

Where are the muscles of facial expression derived from?

2nd pharyngeal arch

14

What structure does the 3rd pharyngeal arch innervate?

Stylopharyngeus

15

What structures does the 4th pharyngeal arch innervate?

Cricothyroid, Levator palatini

16

What structures does the 6th pharyngeal arch innervate?

Intrinsic muscles of the larynx

17

What is the nerve of the 1st arch called?

Trigeminal nerve

18

What does the Trigeminal nerve innervate?

Muscles of mastication
Sensory innervation to the face and lining of mouth and nose

19

What is the nerve of the 2nd arch called?

Facial nerve

20

What does the facial nerve innervate?

Muscles of facial expression
Taste buds of anterior 2/3rds of tongue

21

What is the nerve of the 3rd arch called?

Glossopharyngeal nerve

22

What does the Glossopharyngeal nerve innervate?

Stylopharyngeus and sensory innervation to posterior 1/3rd of the tongue

23

What is the nerve of the 4th and 6th arch?

Vagus nerve
4th branch= superior laryngeal nerve
6th branch= recurrent laryngeal nerve

24

What does the 1st arch cartilage develop into?

Divides into maxillary and mandibular prominences. Mandibular becomes Meckel's cartilage and becomes malleus and incus in the ear. Also provides the template for the mandible

25

What does the second arch cartilage develop into?

Stapes (in middle ear)
Styloid process
Lesser cornu and the upper body of hyoid bone

26

What does the 3rd arch cartilage develop into?

Greater cornu and lower body of hyoid bone

27

What do the 4th and 6th arches cartilage develop into?

Thyroid, arytenoid and cricoid

28

What is the fate of the 1st arch artery?

Disappears

29

What is the fate of the 2nd arch artery?

Disappears

30

What is the fate of the 3rd arch artery?

Internal carotid

31

What is the fate of the 4th arch artery?

Left: Arch of aorta
Right: Brachiocephalic artery

32

What is the fate of the 6th arch artery?

Pulmonary arch

33

Which nerve becomes hooked around the arch of the aorta?

Recurrent laryngeal nerve

34

What is the fate of the 1st pharyngeal pouch?

Tympanic cavity and auditory tube

35

What is the fate of the 2nd pharyngeal pouch?

Palatine tonsil

36

What is the fate of the 4th pharyngeal pouch?

Superior parathyroid

37

What is the fate of the pharyngeal clefts?

The 2nd cleft grows downwards to cover all the other clefts. The 1st cleft is the only one which remains.

38

What happens if a cleft is not fully obliterated?

Remains as a cyst or fistulae