Endocrine Histology

Question 0

What allows blood vessels near endocrine glands to better take up hormones?

Answer 0

Fenestrated endothelium.

Question 1

6 common features of endocrine tissues?

Answer 1

Ductless
Vascular
Organized into blocks, plates, cords (?)
Epithelial (usually)
Polyhedral
Numerous organelles

Question 2

4 “patterns” i.e. tissue types of endocrine cells?

Answer 2

Epithelial
Mesenchymal
Neural
Individual cells

Question 3

From what germ layers are most epithelial endocrine cells derived? What’s one exception?

Answer 3

From ectoderm or endoderm.

Adrenal cortex is exception, being from mesoderm.

Question 4

Which endocrine cells are mesenchymal?

Answer 4

Gonadal endocrine cells that come from mesenchyme - Leydig, granulosa, and luteal cells.

Question 5

Where do neural endocrine cells come from? Two examples?

Answer 5

They come from neural crest cells.
Posterior pituitary cells.
Adrenal medulla cells.

Question 6

Examples of endocrine “individual cells”?

Answer 6

Enteroendocrine cells - those that make, e.g. somatostatin, gastrin.
Juxtaglomerular cells - renin.

Question 7

Where do the two parts of the pituitary come from?

Answer 7

Anterior: From roof of oropharynx, “buccal mucosa,” “Rathke’s pouch”.
Posterior: From neuroectoderm of floor of the 3rd ventricle.

Question 8

6 hormones made by the ant. pit.?

Answer 8

GH, prolactin, FSH, LH, TSH, and ACTH.

Question 9

2 hormones made by the post. pit.?

Answer 9

ADH / vasopressin.

Oxytocin.

Question 10

3 parts of ant. pit.?

Answer 10

Pars distalis - bulk of gland.
Pars intermedia - forms separation form post. pit.
Pars tuberalis - wraps around infundibulum of post. pit.

Question 11

2 parts of the post. pit.?

Answer 11

Pars nervosa - has neurosecretory axons and their endings.

Infundibulum - bridge of neurosecretory axons from hypothalamus to the pars nervosa.

Question 12

Ways to tell ant. and post. pit apart on histolgy?

Answer 12

Ant. pit. is way more vascular.

Post. pit. is composed of axons and glia.

Question 13

3 cell types in the pars distalis of the ant. pit.? What is the function of each?

Answer 13

Acidophiles - Somatotropes (GH) and Lactotropes (PRL)
Basophiles - Corticotropes (ACTH), Gonadotropes (FSH and LH), and Thyrotropes (TSH)
Chromaphobes - function unknown.

Question 14

Which “-trope” cell is most prevalent in the pars distalis?

Answer 14

Somatotropes producing GH.

Question 15

Are the axons of the post. pit. myelinated?

Answer 15

Nope.

Question 16

Fine detail: Which nuclei make oxytocin and ADH?

Answer 16

Oxytocin - made in paraventricular nucleus.

ADH - made in supraoptic nucleus.

Question 17

What are Herring bodies?

Answer 17

Hormones stored in granules in the terminals of axons of in the post. pit.

Question 18

What are glia in the post. pit. called?

Answer 18

Pituicytes

Question 19

Where does thyroid come from embryologically?

Answer 19

Endoderm lining of pharyngeal floor.

Question 20

What’s in the follicles of the thyroid?

Answer 20

Thyroglobulin / aka. colloid - a precursor of thyroid hormone synthesis.

Question 21

What are the 2 types of endocrine cells in the thyroid?

Answer 21

Follicular cells - make T3 and T4
Parafollicular cells (i.e. C cells) - make calcitonin
(each has an associated carcinoma)

Question 22

Where to the parathyroid glands come from?

Answer 22

The 3rd and 4th pharyngial arches.

Question 23

3 main cell types in the parathyroid?

Answer 23

Chief cells - make PTH
Oxyphil cells - function unknown
Adipocytes

Question 24

3 layers of the adrenal cortex? What does each make?

Answer 24

GFR - salt, sugar, and sex
Zona Glomerulosa - mineralocorticoids (mostly aldosterone)
Zona Fasciculata - glucocorticoids
Zona Reticularis - androgens
(note that there is functional overlap between ZF and ZR)

Question 25

Which of the 3 layers of the adrenal cortex is largest?

Answer 25

Zona Fasiculata - making glucocorticoids.

Question 26

What do adrenal adenomas look like?

Answer 26

Giant yellow, steroid-filled, well-circumscribed things.

Question 27

What cells are in the adrenal medulla?

Answer 27

Chromaffin cells, which are axon-less neurons- 2 types: some make NE, other make Epi

Question 28

Reason why the adrenal medulla might be conveniently located?

Answer 28

Cortisol from ZF might inhibit growth of Chromaffin axons, and induce enzymes that convert NE to Epi.

Question 29

What’s a pheochromocytoma?

Answer 29

Tumor of adrenal medulla producing catecholamines. Often presents with hypertension (more on this in the pathology lecture).

Question 30

In what part of the pancreas are islets most numerous?

Answer 30

In the tail.

Question 31

3 major cell types in the islets of Langerhans? (there are others… but..) Where are they generally located within the islet?

Answer 31

alpha cells - make glucagon - on periphery of islet.
beta cells - make insulin - the center of the islet.
delta cells - make somatostatin - scattered throughout islet.

Question 32

About what percent of the pancreas volume to the islets compose?

Answer 32

Only 1-2%