Head and Neck Embryology Flashcards

1
Q

RECAP- what happens after the sperm fertilises the egg?

A

Zygote divides to form blastocyst

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

RECAP- the blastocyst flattens. What does this form?

A

Bilateral disc which then develops into three layers = trilaminar disc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

RECAP- name the three layers of the trilaminar disc.

A

Ectoderm
Mesoderm
Endoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

RECAP- name the space above the ectoderm/.

A

Amniotic cavity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

RECAP- name the space below the endoderm.

A

Yolk sac

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

RECAP- the notochord forms in the trilaminar disc. This is the axis for many developments. However, the notochord does not fully extend from the very top of trilaminar disc to the very bottom.
What happens in these sections?

A

No mesoderm so ectoderm and endoderm fuse.

There are two areas with no mesoderm and these form the mouth and the anus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

RECAP- describe the development of the neural tube.

A

Notochord releases chemicals which causing thickening of ectoderm epithelium. This forms neural crests.
The ends of the neural crests come together and closes, forming the neural tuber which then sinks down away from the ectoderm.

->if you don’[t understand this, watch the Part 1 of Head and Neck Embryology, goes over a recap of what we know so far and might be useful before exam!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

RECAP- what forms from the neural tube?

A

Brain and spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

RECAP- in the process of neural tube formation, what else is produced?

A

Neural crest cells which migrate and give rise to many different structures.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

RECAP- what comes from the paraxial mesoderm?

A

Somites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What do somites go onto develop?

A

Axial skeleton
Muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

RECAP- how many somites are formed in human embryos?

A

33

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

RECAP- what does the ectoderm develop into?

A

Skin

->think, the ectoderm goes around everything

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

RECAP- what does the mesoderm develop into?

A

Muscle, connective tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

RECAP- what does the endoderm develop into?

A

Gut tube

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

RECAP- where does the respiratory tract develop from?

A

Foregut regions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the pharyngeal/brachial arches?

A

Series of arches which develop around the future mouth and pharynx.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

When in the process of embryological development do the pharyngeal/branchial arches develop?

A

Late week 4- week 6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How many branchial arches develop?

A

5

->six start to develop but no.5 disappears leaving us with 1,2,3,4,6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What makes up the branchial arches?

A

Ectoderm- makes outside
Mesoderm- bulky middle section + neural crest cells
Endoderm- lines inside of arch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Which structures develop in the mesoderm of the branchial arches?

A

Blood vessels
Nerves
Skeletal elements

(think about what arises from mesoderm in general)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What else can the ectoderm form in the branchial arches as well as forming the outer layer?

A

Forms clefts between the arches
These clefts can develop into structure like the tongue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What else can the endoderm form in the branchial arches as well as forming the inner layer?

A

Forms pouches between the arches

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Cranial nerves form from the branchial arches.
Which nerve develops from the first branchial arch?

IMPORTANT TO REMEMBER, COMMON EXAM QUESTION

A

Mandibular branch of Trigeminal nerve (CN V3).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Cranial nerves form from the branchial arches.
Which nerve develops from the second branchial arch?

IMPORTANT TO REMEMBER, COMMON EXAM QUESTION

A

Facial nerve (CN VII)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Cranial nerves form from the branchial arches.
Which nerve develops from the third branchial arch?

IMPORTANT TO REMEMBER, COMMON EXAM QUESTION

A

Glossopharyngeal nerve (CN IX).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Cranial nerves form from the branchial arches.
Which nerve develops from the fourth branchial arch?

IMPORTANT TO REMEMBER, COMMON EXAM QUESTION

A

Superior laryngeal branch of the Vagus nerve (CN X)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Cranial nerves form from the branchial arches.
Which nerve develops from the sixth branchial arch?

IMPORTANT TO REMEMBER, COMMON EXAM QUESTION

A

Recurrent laryngeal branch of the Vagus nerve (CN X)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Which nerve innervates all the muscles of face expression of the face?

A

Facial nerve (CN VII)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Therefore, which branchial arch does nerve supplying the face come from?

A

Second branchial arch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is the anterior belly of the digastric muscle innervated by?

A

Mandibular branch of trigeminal nerve

32
Q

What is the posterior belly of the digastric muscle innervated by?

A

Facial nerve

33
Q

Which nerve innervates the muscles of mastication (chewing)?
Which branchial arch will this be developed from?

A

Submandibular branch of trigeminal nerve (CN V3).
Therefore, the muscles of mastication are developed from the first branchial arch.

34
Q

The glossopharyngeal nerve innervates a single muscle. Name it and tell me the branchial arch it developed from.

A

Stylopharyngeus muscle.
This muscle must have developed from the third branchial arch :)

->this makes sense to me when I am writing this but if you need a recap, go over part 2 of the lecture, so well explained!!

35
Q

The superior and recurrent laryngeal nerves (both branches of Vagus nerve) supply the muscles of the vocal cord.
Where will these muscles have developed from?

A

Branchial arches 4&6

36
Q

Skeletal elements also develop from the branchial arches.
Which bones would form from the first branchial arch?

A

Mandible, malleus and incus.

37
Q

Skeletal elements also develop from the branchial arches.
Which bones would form from the second branchial arch?

A

Upper hyoid bone
Stapes
Stylohyoid ligament
Styloid process

38
Q

Skeletal elements also develop from the branchial arches.
Which bones would form from the third branchial arch?

A

Lower part of hyoid bone

39
Q

Skeletal elements also develop from the branchial arches.
Which bones would form from the fourth branchial arch?

A

Thyroid cartilages

40
Q

Skeletal elements also develop from the branchial arches.
Which bones would form from the sixth branchial arch?

A

Lower thyroid cartilage
Cricoid cartilage

41
Q

The clefts and pouches which are formed by the endoderm and ectoderm give rise to structures. Name them.

A

Tongue
Thyroid gland
Parathyroid gland
Part of pituitary gland

42
Q

The face develops from five processes/prominences. Please name them.

A

1 frontonasal process
2 maxillary processes
2 mandibulae processes

43
Q

Where do the two maxillary processes develop from?

A

Maxillary part of first branchial arch

44
Q

Where do the two mandibular processes develop from?

A

First branchial arch

45
Q

Where does the frontonasal process develop from?

A

The mesenchyme superior to the future mouth

46
Q

What happens to the 2 mandibular processes?

A

They fuse together in the midline

47
Q

There is ectodermal thickening in the frontonasal process. What does this form?

A

Nasal placode

48
Q

What happens to the nasal placode?

A

Invaginates to form nostrils

49
Q

The invagination of the nasal placode divides the frontonasal process into two parts. Name them.

A

Lateral nasal process
Medial nasal process

50
Q

What separates the nasal opening from the mouth?

A

Philtrum

51
Q

What do the lateral nasal processes form?

A

Lateral parts of nose

52
Q

What do the medial nasal processes form?

A

Bridge and pointy bit of nose

53
Q

What do the maxillary processes form?

A

Join and form upper lip

54
Q

What do the mandibular processes form?

A

Lower lip

55
Q

What needs to develop in order to separate the nasal and mouth cavities?

A

Palate

56
Q

Describe the formation of the primary palate.

A

Medial nasal process grows downwards and forms the philtrum which forms the primary palate.

57
Q

What happens to the maxillary processes in the development of the palate?

A

Two primary palatine shelves grow inwards

58
Q

How is the secondary palate formed?

A

Palatine shelves meet in the midline to form secondary palate which separates the nasal and oral cavities.

59
Q

Which congenital issue may arise if the maxillary processes do not fully fuse with the philtrum?

A

Cleft lip (harelip)

60
Q

Apart from cosmetic reasons, why would you want to make a diagnosis of cleft lip?

A

No separation between oral and nasal cavities meaning food and drink may be aspirated in the baby

61
Q

Name the three regions of the skull.

A

Cranial vault
Base of skull
Viscerocranium

62
Q

Which type of bones make up the cranial vault of the skull?

A

Flat bones

63
Q

Which type of bones make up the base of the skull?

A

Irregular bones

64
Q

How are the cranial vault bones formed?

A

Formed by membranous ossification calvaria as are membranous bones.

65
Q

How are the base bones of the skull formed?

A

Endochondral ossification

66
Q

What does the viscerocranium do?

A

Forms capsules around sensory special sense organs e.g. eyes

67
Q

Describe the bones of the cranial vault of the skull at birth.

A

Not fully formed
Soft sutures between them
Deformation during birth may occur

68
Q

At what age does the anterior fontanelle close?

A

Approx. 1.5yrs

69
Q

What is meant by a fontanelle?

A

Softer spots on an infant’s head where the bone has not fully fused together

70
Q

What happens if the fontanelles fuse too quickly?

A

Does not provide space for facial skeleton and brain to grow, leading to deformities.

71
Q

Name some deformities seen when the fontanelles fuse too quickly.

A

Craniosynostosis

72
Q

What can happen in craniosynostosis.

A

Abnormal face shape
Sometimes mental retardation

73
Q

How do the base bones of the skull get formed?

A

Initially cartilage which then becomes ossified in the process of endochondral ossification

74
Q

Where do the sensory capsules for the sensory organs develop from?

A

The mesoderm of somites

75
Q
A