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

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

Define placode:

A

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
Q

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

A
  • Inability to suckle/feed

- Impaired speech development

3
Q

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

A
  • Median nasal prominence

- Maxillary prominence

4
Q

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

A

Secondary palatal shelves (maxillary prominences)

5
Q

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

A

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

6
Q

What are the symptoms of Foetal Alcohol Syndrome?

A
  • Microcephaly
  • Epicanthal folds
  • Small eye openings
  • Short nose
  • Smooth philtrum
  • Underdeveloped jaw
7
Q

What happens to the pharyngeal clefts in the developing embryo?

A

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

8
Q

Where do branchial cysts occur?

A

Anterior border of SCM

9
Q

How does a branchial cyst develop?

A

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

10
Q

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

A

20 deciduous teeth ~ 6-30 months

28 permanent teeth (+ wisdom = 32) ~ 6-13 yrs

11
Q

What is Rathke’s pouch?

A

Invagination of ectoderm which forms the anterior pituitary

12
Q

What tissue does the anterior pituitary derive from?

A

Ectoderm

13
Q

What tissue does the posterior pituitary derive from?

A

Neuro-ectoderm

14
Q

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

A

Ossification of the sphenoid bone

15
Q

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

A

via the Lingual frenulum

16
Q

What marks the point of origin of the thyroid gland?

A

Foramen cecum

17
Q

Describe the migration of the thyroid gland:

A
  • From the foramen cecum
  • Down thryroglossal duct
  • Ant. to pharynx, hyoid bone + laryngeal cartilages
18
Q

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

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