15 - Head + Neck - Development (Face + Midline structures) Flashcards Preview

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Flashcards in 15 - Head + Neck - Development (Face + Midline structures) Deck (18):
1

Define placode:

An area of ectoderm in the embryonic head which begins to thicken and differentiate itself from the surrounding tissue
Ex: lens, nasal and otic placodes of the developing face

2

What are the main complications of a cleft lip + palate?

- Inability to suckle/feed
- Impaired speech development

3

A cleft lip is the failure of fusion of which structures?

- Median nasal prominence
- Maxillary prominence

4

A cleft palate is the failure of fusion of which structures?

Secondary palatal shelves (maxillary prominences)

5

Why does alcohol have such a profound effect on the developing head and neck of an embryo?

It kills neural crest cells and affects their migration and subsequent brain development

6

What are the symptoms of Foetal Alcohol Syndrome?

- Microcephaly
- Epicanthal folds
- Small eye openings
- Short nose
- Smooth philtrum
- Underdeveloped jaw

7

What happens to the pharyngeal clefts in the developing embryo?

2nd pharyngeal arch grows down and obliterates the clefts below, such that only the 1st cleft remains (= EAM)

8

Where do branchial cysts occur?

Anterior border of SCM

9

How does a branchial cyst develop?

Formed if the 2nd pharyngeal cleft is not obliterated completely by the 2nd pharyngeal arch during development

10

How many deciduous and permanent teeth are there, and when do they begin to erupt?

20 deciduous teeth ~ 6-30 months
28 permanent teeth (+ wisdom = 32) ~ 6-13 yrs

11

What is Rathke's pouch?

Invagination of ectoderm which forms the anterior pituitary

12

What tissue does the anterior pituitary derive from?

Ectoderm

13

What tissue does the posterior pituitary derive from?

Neuro-ectoderm

14

What causes Rathke's pouch to be pinched off from the ectoderm?

Ossification of the sphenoid bone

15

How is the tongue attached to the floor of the mouth?

via the Lingual frenulum

16

What marks the point of origin of the thyroid gland?

Foramen cecum

17

Describe the migration of the thyroid gland:

- From the foramen cecum
- Down thryroglossal duct
- Ant. to pharynx, hyoid bone + laryngeal cartilages

18

How can you tell the difference between a thyroglossal and branchial cyst?

Thyroglossal = in midline
Branchial = along ant. border of SCM