Endocrine Embryology - Bendiak

Question 1

The front part of the tongue is derived from____?

Answer 1

Oral ectoderm. This merges with the pharynx which is derived from endoderm.

Question 2

The digestive tract is derived from ____?

Answer 2

Endoderm.

Question 3

What is the stomodeum?

Answer 3

The mouth opening. Ectoderm derived.

Question 4

At four weeks gestation, the lower part of the neural ectoderm forms the ______.

Answer 4

Posterior pituitary and the central portion of the infundibular stalk. (makes sense, as this is essentially an extension of the hypothalamus).

Question 5

The anterior pituitary develops from _____?

Answer 5

Oral ectoderm from the upper mouth (Specifically, Rathke’s pouch)

Question 6

Name the parts of the pituitary that arise from

a) oral ectoderm (rathke’s pouch)
b) neural ectoderm

Answer 6

a) Anterior pitiutary (Pars intermedia, tuberalis, distalis),
b) Posterior pituitary (Pars nervosa and infundibular stalk)

Question 7

The thyroid develops from _____.

Answer 7

Endoderm. It is later invaded by mesoderm (blood supply).

Question 8

The inferior parathyroid glands arise from the _____.

Answer 8

Cleft between the 3rd/4th pouches. No, it’s not a typo. The superior originates below the inferior.

Question 9

The superior parathyroid gland arises from the ____.

Answer 9

CLeft underneath the 4th pouch. No, it’s not a typo. The superior originates below the inferior. They migrate downwards and end up in the proper position for their name.

Question 10

The thyroid begins as a medial evagination of the endoderm called the ______, which begins to extend at about the region between the first and second pharyngeal pouches.

Answer 10

thyroid diverticulum

Question 11

What strucure gives rise to the calcitonin-secreting cells of the parathyroid?

Answer 11

The parafollicular cells secrete calcitonin. They are derived from a structure called the ultimobranchial body, which arises from neural crest cells (ectoderm).

Question 12

The thyroid diverticulum enlarges and descends along the pharynx with the developing thyroid initially attached via the _________. The thyroid gland descends to a region under the larynx, just in front of the trachea.

Answer 12

thyroglossal duct

Question 13

The adrenal glands are comprised of a cortex and medulla. The cortex originates from _____ whereas the medulla is of ____ origin.

Answer 13

cortex = mesoderm

medulla = ectoderm

Question 14

What are chromaffin cells?

Answer 14

Cells of the adrenal medulla that secrete NE/E.
Pheochromocytomas arise from these cells.
Chromaffin cells arise from neural crest cells.