Endo

Question 1

From what embryonic tissue is the posterior pituitary derived?

Answer 1

The neuroectoderm

Question 2

What are the three layers of the adrenal cortex? What do they secrete?

Answer 2

1. zona glomerulosa
2. zona fasiculata
3. zona reticulata
4. mineralocorticoids (aldosterone)
5. glucocorticoids (cortisol)
6. sex hormones (androgen)

Question 3

What is the primary regulatory control of the (three layers of) the adrenal cortex?

Answer 3

1. zona glomerulosa - renin, angiotensin
2. zona fasiculata - ACTH, CRH
3. zona reticulata - ACTH, CRH

Question 4

What cells compose the adrenal medulla? From what embryonic structure/cells do these arise?

Answer 4

chromaffin cells

They arise from the neural crest

Question 5

What is the drainage of the left and right adrenal glands?

Answer 5

left: left adrenal vein –> left renal vein –> IVC
right: right adrenal vein –> IVC

Question 6

From what embryonic tissue is the anterior pituitary derived?

Answer 6

From the oral ectoderm (Rathke pouch)

Question 7

From what embryonic tissue is the adrenal cortex derived?

Answer 7

Mesoderm

Question 8

What hormones are secreted by the anterior pituitary?

Answer 8

FSH

LH

ACTH

TSH

Prolactin

GH

MSH

Question 9

What cells make up the endocrine pancreas? What do they secrete?

Answer 9

alpha cells - glucagon

beta cells - insulin

delta cells - somatostatin

Question 10

What is the overall architecture of the cells of the endocrine pancreas?

Answer 10

The beta cells are on the inside, the alpha cells are on the outside, and the delta cells are interspersed among the beta cells.

Question 11

What hormones are secreted by the hypothalamus?

Answer 11

GnRH

CRH

TRH

Dopamine

Somatostatin

GHRH

Question 12

What is the function of CRH?

Answer 12

Corticotropin Releasing Hormone stimulates the anterior pituitary to secrete:

ACTH

MSH

ß-endorphins

Question 13

What is the function of dopamine that is secreted by the hypothalamus?

Answer 13

It inhibits the secretion of prolactin by the anterior pituitary

Question 14

What is the function of GnRH?

Answer 14

Gonadotropin Releasing Hormone functions to stimulate secretion of FSH and LH from the anterior pituitary.

Question 15

What is the function of somatostatin secreted by the hypothalamus?

Answer 15

Inhibits secretion of GH and TSH by the anterior pituitary

Question 16

What is the function of TRH?

Answer 16

Stimulates secretion of TSH and prolactin by the anterior pituitary.

Question 17

What is the function of prolactin?

Answer 17

1. stimulates milk production
2. inhibits ovulation in females and spermatogenesis in males by inhibiting GnRH release
3. excessive amounts of prolactin are assoicated with decreased libido

Question 18

What stimulates prolactin secretion?

Answer 18

1. TRH
2. estrogen
3. dopamine antagonists

Question 19

What inhibits prolactin secretion?

Answer 19

1. dopamine
2. dopamine agonists (e.g., bromocriptine)

**Dopamine agonists are the first-line treatment for a prolactinoma

Question 20

What is the function of Growth Hormone (GH)?

Answer 20

GH stimulates linear growth and muscle mass via stimulating the liver to produce IGF-1

Question 21

Describe the regulation of GH?

Answer 21

GH is released is pulses in response to GHRH.

Secretion increases during sleep and exercise.

Secretion is inhibited by glucose and somatostatin.

Question 22

How is ADH secretion regulated?

Answer 22

ADH secretion is increased in response to increased serum osmolality and decreased blood volume.

primary regulation: osmoreceptors in the hypothalamus

secondary regualtion: hypovolemia.

Question 23

Relative to normal, what are the ADH levels in central diabetes insipidus?

Answer 23

low/decreased

Question 24

Relative to normal, what are the ADH levels in nephrogenic diabetes insipidus?

Answer 24

normal or elevated

Question 25

What is the treatment for central diabetes insipidus?

Answer 25

Desmopressin (an ADH analog)

Question 26

What is the source of cortisol?

Answer 26

The zona fasiculata of the adrenal cortex

Question 27

Describe the regulation of cortisol?

Answer 27

CRH (from the hypothalamus) stimulates ACTH release (from the anterior pituitary), which stimulates cortisol production in the adrenal zona fasiculata. Excess cortisol feedback inhibits CRH, which decreases ACTH, and thus decreases cortisol production and secretion. \*\*Chronic stress induces prolonged cortisol secretion.

Question 28

Briefly, what are the effects/functions of cortisol?

Answer 28

1. increases BP 2. increases insulin resistance 3. increases gluconeogenesis, lipolysis, and proteolysis 4. decreases fibroblast activity 5. decreases inflammatory and immune response 6. decreases bone formation

Question 29

What does cortisol increase blood pressure?

Answer 29

Cortisol **increases the expression of alpha-1 adrenergic receptors on arterioles** --\> increases blood vessel sensitivity to norepinephrine and epinephrine --\> increased blood pressure. \*\*Cortisol is essential for life, and is required to maintain vascular tone. A lack of cortisol can lead to fatal hypotension.

Question 30

How does cortisol decrease the inflammatory and immune response?

Answer 30

Cortisol: 1. inhibits phospholipase A2, and therefore inhibits prostaglandin and leukotriene production 2. inhibits leukocyte adhesion --\> neutrophilia 3. blocks histamine release from mast cells 4. Blocks the production of IL-2 5. decreases the number of eosinophils

Question 31

Why are abdominal straie observed in a high cortisol state?

Answer 31

Cortisol **decreases fibroblast activity, which impairs collagen formation**. This causes blood vessels to become weaker and more prone to rupture. The straie are due to ruptured blood vessels.

Question 32

Why does cortisol decrease bone formation?

Answer 32

Because cortisol decreases osteoblast activity.

Question 33

Why is cortisol diabetogenic?

Answer 33

cortisol **increases insulin resistance**