3) Development of Head & Neck (1) Flashcards Preview

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Flashcards in 3) Development of Head & Neck (1) Deck (40)
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1
Q

What are the pharyngeal (branchial) arches?

A

Sequence of ridges that from in the lateral walls of the embryonic pharynx (at cranial end of neural tube)

2
Q

What are the three regions in the adult pharynx?

A

Nasal - superior to soft palate
Oral - between soft palate and larynx
Laryngeal - posterior to larynx

3
Q

How many pharyngeal arches are there?

A

5, number 1-6

4
Q

What is superior to the pharyngeal arches?

A

Frontonasal prominence which is in front of the brain

5
Q

Describe how the arches are arranged (embryonic tissues):

A

Mesenchyme core with neural crest cells
Covered by ectoderm on external surface (between arches are clefts)
Covered by endoderm on internal surface (pharyngeal pouches)

6
Q

What does each arch have associated with it?

A

Artery, nerve and cartilage bar

7
Q

What are the three regions of primitive brain?

A

Forebrain - prosencephalon
Midbrain - mesencephalon
Hindbrain - rhombencephalon

8
Q

How many pairs of cranial nerves are there?

A

12

9
Q

How are the cranial nerves classified?

A

Function and embryological origin

10
Q

Where are the cranial nerves derived from?

A

Apart from I and II, mid or hind brain

11
Q

Which cranial nerves are associated with the pharyngeal arches?

A

V, VII, IX and X

12
Q

Which cranial nerves have a relationship with the pharyngeal arch system?
(not associated with an arch)

A

CN XI (cranial accessory) and CN XII

13
Q

What is the facial skeleton derived from?

A

Frontonasal prominence and 1st pharyngeal arch

14
Q

What nerve is associated with the 1st pharyngeal arch?

And what is the sensory supply?

A

CN V, trigeminal nerve

Skin of face

15
Q

What nerve is associated with the 2nd pharyngeal arch?

And what is the sensory supply?

A

CN VII, facial nerve

Anterior 2/3rd tongue, taste buds

16
Q

What nerve is associated with the 3rd pharyngeal arch?

And what is the sensory supply?

A

CN IX, glossopharyngeal nerve

Posterior 1/3rd tongue

17
Q

What nerve is associated with the 4th pharyngeal arch?

A

CN X, vagus nerve (superior laryngeal branch)

18
Q

What nerve is associated with the 6th pharyngeal arch?

A

CN X, vagus nerve (recurrent laryngeal branch)

19
Q

Which muscles are 1st arch derivatives?

A

Muscles of mastication

digastric, mylohyoid

20
Q

Which muscles are 2nd arch derivatives?

A

Muscles of facial expression

21
Q

Which muscle is a 3rd arch derivatives?

A

Stylopharyngeus

22
Q

Which muscles are 4th arch derivatives?

A
Pharyngeal muscles (constrictors)
Cricothyroid
23
Q

Which muscles are 6th arch derivatives?

A

Intrinsic muscles of the larynx

24
Q

What skeletal structures are derived from the 1st arch?

A

Meckel’s cartilage - template for mandible + malleus and incus
Maxillary and zygomatic bones

25
Q

What skeletal structures are derived from the 2nd arch?

A

Reichert’s cartilage - stapes, upper body of hyoid and lesser horn, styloid process and stylohyoid ligament

26
Q

What skeletal structures are derived from the 3rd arch?

A

Lower body of hyoid and greater horn

27
Q

What skeletal structures are derived from the 4th arch?

A

Thyroid cartilage
Cricoid cartilage
Epiglottis (with 3rd)

28
Q

What skeletal structures are derived from the 6th arch?

A

Arytenoid cartilage

29
Q

Which arteries are associated with the 1st and 2nd arch?

A

Arteries disappear so none

30
Q

Which arteries are associated with the 3rd arch?

A

Internal carotid arteries

31
Q

Which arteries are associated with the 4th arch?

A

Arch of aorta (L) and brachiocephalic trunk (R)

32
Q

Which arteries are associated with the 6th arch?

A

Pulmonary arch

33
Q

What is derived from the 1st pharyngeal pouch?

A

Eustachian tube, tympanic cavity and middle ear cavity

34
Q

What is derived from the 2nd pharyngeal pouch?

A

Palatine tonsil

35
Q

What is derived from the 3rd pharyngeal pouch?

A

Inferior parathyroid and thymus

36
Q

What is derived from the 4th pharyngeal pouch?

A

Superior parathyroid and C cells of thyroid

37
Q

What happens to the pharyngeal clefts?

A

1st is all that remains as 2nd arch grows down to cover others

38
Q

What does the 1st pharyngeal cleft form?

A

External auditory meatus of ear

39
Q

What can occur if clefts or cervical sinus remains?

A

Branchial cysts or fistulae

40
Q

Where are cysts likely to form?

A

Anterior border of sternocleidomastoid