Head and Neck Embryology Flashcards

1
Q

What does the neck form from?

A

Branchial/pharyngeal arches

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

What does the face form from?

A

5 mesenchymal processes / prominences

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

Where does the skull develop from?

A

Mesenchyme in the head region of developing embryo

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

What is mesenchyme?

A

Mesenchyme is embryonic connective tissue

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

What is the development of the blastula?

A

Forms bilaminar disk - forms trilaminar disk.

Trilaminar disk contains amniotic cavity dorsally (ectoderm) and yolk sak ventrally (endoderm side)

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

What leads to axis formation of the embryo?

A

Notochord formation

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

What does the neural tube form from?

A

Forms from the ectoderm in the midline - forms - brain and spinal cord

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

What does the neural crest form from?

A

Some cells at the crest of the neural fold separate to form the neural crest cells

(neural crest is seen here as the green)

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

What happens to the neural crest cells?

A

They migrate and give rise to a wide variety of structures. The neural crest cells in the head and neck region mix with the mesoderm.

The neural crest cells give rise to a wide variety of structures - migrate for example dorsal root ganglia, sympathetic chain and autonomic plexus

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

Where do somites arise from?

A

Paraxial mesoderm

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

What do somites form?

A

Form structures like the axial skeleton and the muscles

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

How many somites develop in humans?

A

33 in total

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

What are pharyngeal branches?

A

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

They support the primitive pharynx

Face and neck develop from the

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

What embryolgical tissue makes up the branchial arches?

A

Ectoderm lines the outside and forms celfts between the arches

Mesoderm in the middle - cartilage nad muscle

Endoderm on the inside - forms pouches in between arches

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

What are the nerves of the branchial arches?

A

1st arch - mandibular branch of trigeminal

2nd - arch facial nerve

3rd - arch glossopharyngeal n.

4th - arch superior laryngeal branch of vagus

(no 5th arch)

6th - arch recurrent laryngeal branch of vagus

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

What are the muscles of the face innervated by?

A

Facial nerve

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

If the facial nerve supplies muscles of the face, which branchial arch did they arise from?

A

From the 2nd arch

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

What innervates the digastric muscle?

A

Anterior belly - mandibular division of the trigeminal nerve

Poesterior belly - facial nerve

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

What cartilages form from the 1st branchial arch?

A

Meckels cartilage

Maleus

Incus

20
Q

What cartilages form from the 2nd branchial arch?

A

Stapes

Styloid process

Stylohyoid ligament

21
Q

What cartilage forms from the third branchial arch?

A

Greater horn of the hyoid bone

22
Q

What cartilage forms from the 4th branchial arch?

A

Thyroid cartilage

23
Q

What cartilage forms from the 6th branchial arch?

A

Cricoid cartilage

24
Q

What are pther important structures developing from the branchial arches?

A
  • Tongue
  • Thyroid gland
  • Parathyroid gland
  • Part of the pituitary gland
25
Q

What are the 5 prominences that the face develops from?

A

The frontonasal process

Two maxillary processes

Two mandibular processes

26
Q

Where does the frontonasal process come from?

A

From mesenchyme superior to future mouth

27
Q

Where do themaxillary processes come from?

A

From maxillary part of first branchial arch mesenchyme

28
Q

Where do the mandibular processes come from?

A

1st arch mesoderm

29
Q

What is the activity of the 2 mandibular processes?

A

They fuse in the midline

30
Q

How is the nasal pit formed?

A

Ectodermal thickening (nasal placode) pushes inwards to form the nasal pit

31
Q

How is the philtrum formed?

A

The medial nasal process further grows downwards and laterally

32
Q

Which colour in the picture represents the philtrum?

A

Green portion just below the nose

33
Q

What are the stages of development of the palate?

A

Stage 1: Philtrum forms by downward growth of the medial nasal process. This is known as the primary palate.

Stage 2: 2 palantine shelves grow inwards from the maxillary processes

Stage 3: Palantine shelves meet in the midline to form the secondary plate

Oral and nasal cavity are now complete.

34
Q

What are the three bony regions of the head?

A

Cranial vault

Base of the skull

Viscerocranium

35
Q

What bones form the cranial vault and how are they formed?

A

Flat bones - formed by membranous ossification calvaria

36
Q

What bones form the base of the skull and how are they formed?

A

Irregular bones - endochondral ossification

37
Q

How are the bones of the viscerocranium formed?

A

Partly from branchial arches, and partly from sensory (special sense) capsules

38
Q

Where does the mesenchyme aris from that is involve in skull vault ossification?

A

Mesenchyme is derived from the mesoderm and lies above the surface of developing brain - ossifies directly (membranous ossification)

39
Q

Why are sutures soft in the skull vault?

A

Allows deformation during passage through birth canal

40
Q

How many fontanelle are of clinical significance?

A

6

41
Q

What are fontanelle?

A

A space between the bones of the skull in an infant or fetus, where ossification is not complete and the sutures not fully formed. The main one is between the frontal and parietal bones.

42
Q

Where does the mesenchyme arise from that forms the base of the skull?

A

It is found around the notochord and is derived predominantly from neural crest cells

43
Q

How are the bones of the base of the skull formed?

A

Preform in cartilage

Later they ossify

44
Q

Where are sensory capsules formed?

A

Derived from mesoderm of somites in head and neck region

45
Q

What do sensory capsules form?

A

Preform in cartilage and ossify to form bones around the sense organs

nose, eye and ear

They form partly base of skull, partly viscerocranium

46
Q
A