Development of the endocrine glands

Question 1

Which week does the pituitary gland begin to develop?

Answer 1

Week 6

Question 2

What does the pituitary gland develop from?

Answer 2

2 sources:

• ectoderm of oral cavity
  [] invaginates to form Rathke’s pouch
• neuroectoderm
  [] invaginates to create neurophyseal diverticulum (becomes infundibulum)

Question 3

What happens from week 11 in the development of the pituitary?

Answer 3

Tissues associated

• anterior lobe
• posterior lobe
• hypophysial fossa

Question 4

What forms the anterior lobe of the pituitary?

Answer 4

Pharyngeal ectoderm

Question 5

What forms the posterior lobe of the pituitary?

Answer 5

Neuroectoderm

Question 6

What forms the hypophysial fossa?

Answer 6

Sphenoidbonebeginstosurroundinferiorly

Question 7

When is the pituitary gland fully formed?

Answer 7

In week 16

• optic chiasm also formed above

Question 8

In adult life describe the pituitary gland?

Answer 8

Anterior lobe (adenohypophysis)
 - glandular with rich blood supply

Posterior lobe (neurohypophysis)
 - Nervous part - contains axons originating in hypothalamus which secrete oxygen and vasopressin into blood

Question 9

What is the adrenal medulla formed from?

Answer 9

Neural crest cells (neuroectoderm)

Question 10

What is the adrenal cortex formed from?

Answer 10

Mesoderm
- neural crest cells migrate to form sympathetic ganglion and some continue into mesoderm, pushing in amongst cells that are developing into adrenal cortex

Question 11

What is the thyroid formed from?

Answer 11

Thyroid diverticulum develops from endoderm at foramen caecum (V shaped angle at back of tongue)

Descends along midline leaving thyroglossal duct behind

Question 12

What do the parafollicular ‘C’ cells form from?

Answer 12

Develop from neural crest cells descending from 4th pharyngeal pouch

Catch up and embed themselves in thyroid, forming C cells (produce calcitonin)