Endo Development

Question 1

Pituitary gland precursor

Answer 1

Ectoderm

Question 2

Thyroid gland precursor

Answer 2

Endoderm

Question 3

Parathyroid gland precursor

Answer 3

Endoderm

Question 4

Adrenal gland precursor

Answer 4

Mesoderm

Question 5

Whats the difference between how exocrine and endocrine glands form??

Answer 5

Exocrine –> Epithelium maintains connection with epithelium and forms duct and secretory components
Endocrine –> loses its connection with epithelium of origin, forms rich capillary plexus; release hormones early in the fetal period

Question 6

What are the two ectoderm primordial that form the pituitary gland?

Answer 6

Oral ectoderm - Hypophyseal diverticulum/Rathke’s pouch

Neural ectoderm - Infundibulum

Question 7

Hypophyseal diverticulum (Rathke’s Pouch) anterior wall becomes…

Answer 7

distal lobe of pituitary

Question 8

Hypophyseal diverticulum (Rathke’s Pouch) superior extension becomes…

Answer 8

tuberal lobe of pituitary

Question 9

Hypophyseal diverticulum (Rathke’s Pouch) posterior wall becomes…

Answer 9

intermediate lobe of pituitary

Question 10

What forms the infudibulum?

Answer 10

median eminence + pituitary stalk + neural lobe

Question 11

Remnants of Rathke’s pouch remaining in the roof of pharynx

Answer 11

Pharyngeal hypophysis

Question 12

Tumor forming from Rathke’s pouch remnants

Answer 12

Craniopharyngioma

• Usually forms in the sella turcica
• Can impinge the optic chiasm

Question 13

How does formation of the thyroid gland begin?

Answer 13

As a midline invagination of pharyngeal endoderm.

Question 14

When does the thyroid gland arrive at its definitive location?

Answer 14

Week 7

Inferior to the cricoid cartilage and anterior to the trachea

Question 15

What do the ultimo pharyngeal bodies become?

Answer 15

They detach from the pharyngeal pouch and migrate toward the thyroid diverticulum
They are invaded by neural crest cells before separation from the pharynx and eventually become Parafollicular cells or C cells in the thyroid gland – they produce calcitonin

Question 16

What is the most common location for aberrant thyroid tissue?

Answer 16

At the base of the tongue - but can be anywhere along the path of the thyroid

Question 17

What forms the parathyroid?

Answer 17

Form from pharyngeal pouches 3 and 4

Question 18

What forms the adrenal cortex?

Answer 18

Proliferating coelomic epithelial cells during week 4-5

Question 19

What is the primary wave?

Answer 19

During week 5, a subset of proliferating cells separates from the coelomic epithelium and enters the underlying mesenchyme = primary wave of adrenal cortical progenitor cells
Forms the fetal adrenal cortex

Question 20

What is the second wave?

Answer 20

A second wave of proliferating cells separates from the epithelium and enters the underlying mesenchyme where they surround the cells of the primary wave
Forms the definitive adrenal cortex

Question 21

What does the definitive adrenal cortex organize into?

Answer 21

Three zone of the adrenal cortex - zona glomerulosa, zone fasiculata, zone reticularis

Question 22

How does the pineal gland develop and what does it do?

Answer 22

Midline, dorsal diverticulum of the roof of the diencephalon – visible by week 10
Secretes melatonin