Session 11 - Development Of the Midline Structures Flashcards Preview

ESA 4 - Head and Neck > Session 11 - Development Of the Midline Structures > Flashcards

Flashcards in Session 11 - Development Of the Midline Structures Deck (21)
1

Where does the pituitary gland sit?

Pituitary fossa of sphenoid bone

2

What are the 2 parts of the pituitary gland?

Anterior and posterior

3

What is the precursor of the anterior lobe of the pit gland and its origin?

Precursor - Rathke's pouch

Origin - ectoderm

4

What is the origin of posterior lobe of pit gland?

Origin - neuroectoderm

5

Which lobe is derived from the brain?

POsterior lobe 

6

Describe how the pituitary gland is formed.

  1. Infundibulum extends down towards roof of oral cavity
  2. Outpushing from roof grows up to meet it (Rathke's Pouch) and it oses its connection with roof of mouth
  3. Pouch comes to lie anterior to infundibulum 
  4. Pouch differentiates to cells of ant pit.
  5. Hypophyseal portal system links hypothalamus to pituitary gland.

7

What might happen to any remnants of rathke's pouch?

Could form cysts

8

What week does the tongue appear in?

4th

9

How many lateral and medial lingual swellings are there? What are they each derived from?

2 lateral - 1st PA

3 medial - 1st to 4th PA

10

Whats the name of the 3 medial lingual swellings and which PA is each derived from?

1st PA - Tuberculum impar

2nd and 3rd PA - cupola

4th PA - Epiglottal swelling

11

Describe the development of the tongue

  1. Lateral swelling overgrow tuberculum impar
  2. 3rd Arch part of cupola overgrows its second Arch component
  3. Degeneration occurs, freeing tongue from floor of oral cavity except lingual frenulum

12

What innervates the special sensation of tongue?

anterior 2/3rds - Chorda Tympani 

posterior 1/3rd - Glossopharyngeal

13

What is the general innervation of the tongue?

Anterior 2/3rds - Lingual (comes from mand branch of trigeminal)

Posterior 1/3rd  - Glossopharyngeal

14

What innervates the muscles of the tongue?

All muscles except palatoglosssus - Hypoglossus nerve

Palatoglosssus - Vagus nerve

15

Where does the thyroid gland first appear in development?

Between tuberculum Impar and cuploa of tongue at site called foramen cecum

16

Describe the descent of the thyroid gland

Thyroid bifurcates and descends as bi-lobed 

During descent remains connected to tongue by thryoglossal duct

17

What are the 2 cell types in the thyroid gland and their secretions?

Follicular cells - T3 and T4

Parafolicular cells - Calcitonin

18

where can ectopic thyroid tissue be found?

anywhere along path of descent of thyroid gland

19

What is first arch syndrome? What is the usual result

failure of colonisation of 1st arch with neural crest cells

Usual result is hypoplasia of mandible and facial bones

20

What is DiGeorge Syndrome?

CATCH 22

Cardiac abnormalities

Abnormal facies

Thymic hypoplasia

Cleft palate

Hypocalcaemia

Chromosome 22 abnormalities

21

What is CHARGE syndrome? What is it caused by?

CHARGE

Coloboma (hole in iris
Heart defects
Atresia (blockage of posterior nasal cavity)
Retardation of growth and development
Genital hypoplasia
Ear defects

 

CHD7 mutation, essential for production of multipotent nerual crest cells