Development of the Head and Neck 1 Flashcards Preview

B - Embryology for EoY4 > Development of the Head and Neck 1 > Flashcards

Flashcards in Development of the Head and Neck 1 Deck (115)
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1

What does the fetal skull have, that the adult skull doesn't? 

Fontanelles

2

What are fontanelles? 

Membranous areas of unfused skull 

3

When will the fontanelles be closed? 

Within the first 2 years of life 

4

What is the function of fontanelles? 

  • Flexibility allows passage through the birth canal 
  • Allow for brain growth

 

5

What changes in the fontanelles can indicate pathology? 

  • Sunken
  • Bulging 
  • Enlarged

 

6

What do sunken fontanelles indicate? 

Dehydration 

7

What do bulging fontanelles indicate? 

Increased intracranial pressure 

8

When do enlarged fontanelles often occur? 

In prematurity 

9

What is the problem with enlarged fontanelles? 

They can squash the brain, causing brain damage

10

When does the neural tube form?

Week 3 

11

How is the neural tube formed? 

  • The notocord is formed at gastrulation 
  • The notocord sends signals causing the overlying ectoderm to thicken
  • Edges of the ectoderm elevate out of slipper-shaped neural plate, out of the plane of the disc
  • Edges curl towards one another, creating neural tube

12

What happens to the anterior end of the neural tube? 

It begins to form the brain 

13

Describe the anterior end of the neural tube when it's beginning to form brain? 

Initially in 3 vesicle stage, and vesicles quickly specialise 

14

What do the vesicles of the neural tube specialise to form? 

  • Prosencephalon - forebrain
  • Mesencephalon - midbrain
  • Rhombencephalon - hindbrain

 

15

What has happened to the embryo by the end of week 4? 

It has folded 

16

What helps to fold the embryo? 

The growth of the neural tube

17

What does folding of the embryo create? 

Primitive gut tube 

18

Does the primitive gut tube include the primitive pharynx? 

Yes 

19

What is the primitive gut tube lined with? 

Endoderm 

20

Describe the head and neck region of the embryo early in week 4? 

  • Face has no distinguishing external features
  • Head and neck represent half the length of the embryo
  • There is an open pore in the neural tube cranially and caudally, which is fusing from the middle upwards

 

21

Where does the pharynx extend in the adult? 

From the base of the skull to the inferior border of the cricoid cartilage of the larynx

22

What are the divisions of the pharynx? 

  • Nasal 
  • Oral 
  • Laryngeal 

 

23

Where is the nasopharynx? 

Superior to the soft palate

24

Where is the oropharynx? 

Between the soft palate and the larynx 

25

Where is the laryngopharynx? 

Posterior to the larynx 

26

What are the pharyngeal (or brachial) arches? 

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

27

Where do the pharyngeal arches form? 

In the lateral walls of the embryonic pharynx, towards the cranial end of the neural tube

28

What gives the bumps of the pharyngeal arches? 

Lots of cell division and plastic mesenchyme production 

29

What are the pharyngeal arches involved in? 

Formation of the head and neck 

30

What type of tissues do the pharyngeal arches give rise to?

  • Muscles
  • Cartilages
  • Nerves
  • Arteries