Adrenocortical Hormones GUyton

Question 1

What are the 3 layers of the adrenal cortex

Answer 1

Zona glomerulosa

Zona fasciculata

Zona reticularis

Question 2

What is secreted in the zona glomerulosa

Answer 2

Aldosterone

Question 3

What controls aldosterone secretion from the adrenal gland? (2)

Answer 3

Angiotensin II and potassium

Question 4

What is secreted in the zona fasciculata?

Answer 4

Cortisol and corticosterone

Question 5

What controls cortisol secretion for the adrenal gland?

Answer 5

ACTH

Question 6

What is secreted by the zona reticularis?

Answer 6

adrenal androgens

Question 7

What controls secretion of adrenal androgens from the adrenal gland?

Answer 7

ACTH +/- cortical androgen hormone

Question 8

What molecule is required to synthesize any adrenal hormone?

Answer 8

Cholesterol (LDL)

Question 9

What is the rate limiting step to the formation of adrenal steroids?

Answer 9

Desmolase cleaving the LDL cholesterol to form pregnenolone

Question 10

What are two things that can increase the conversion of cholesterol to prenenolone?

Answer 10

ACTH and angiotensin II

Question 11

What is the most potent mineralocorticoid?

Answer 11

Aldosterone

Question 12

What is the most potent gluccocorticoid?

Answer 12

Cortisol

Question 13

Does cortisol have any mineralocorticoid activity?

Answer 13

Yes, but minimal

Question 14

How much more potent is prednisone when compared to cortisol? What about dexamethasone?

Answer 14

Prednisone = 4

Dexamethasone = 30

Which makes sense that dex is 7x more potent than prednisone

Question 15

What is the half life of aldosterone once in the bloody?

Answer 15

20 minutes

Question 16

What blood work changes would you expect with excess aldosterone? (3)

Answer 16

Hyperkalemia

Hyponatremia

Hypochloremia

Question 17

Which cells in the kidney are targets for aldosterone? Where are these cell?

Answer 17

Principle cells, in the late distal convoluted and early collecting ducts

Question 18

In the kidney, which channel is upregulated in the face of aldosterone?

Answer 18

ENaC

Question 19

What other primary site does aldosterone target to retain sodium?

Answer 19

Colon

Question 20

How does excess aldosterone effect potassium?

Answer 20

Causes it to be exchanged with sodium in principle cells and excreted in the urine

Question 21

How does aldosterone effect hydrogen? Where does this effect occur? What does it lead to?

Answer 21

Exchanges hydrogen ions for sodium.

Intercalated cells of the collecting tubules

Metabolic alkalosis

Question 22

Why may an addisonian patient have diarrhea?

Answer 22

Lack of sodium absorption in the colon, leads to water also osmotically being pulled to the colon.

Question 23

What are two changes that would increase aldosterone secretion?

Answer 23

hyperkalemia

RAAS (increased AGII)

Question 24

Does ACTH control the rate of aldosterone secretion?

Answer 24

No, but it is permissable and required for aldosterone secretion. But aldosterone will secrete however much is needed regardless of how much ACTH stimulated it.

Question 25

How does cortisol effect carbohydrate metabolism? (2)

Answer 25

Stimulates gluconeogenesis in the liver and decreases glucose uptake into the cells

Question 26

How does cortisol effect protein storage?

Answer 26

Reduction of protein in all parts of the body except the liver

Question 27

How does cortisol effect fat metabolism?

Answer 27

Causes mobilization of FFA from adipose tissue in the plasma

Question 28

What are the 5 stages of inflammation?

Answer 28

1) Damaged tissue release chemical substances (histamine, bradykinin, proteolytic enzymes, prostaglandins, leukotrines) 2) Increased in blood flow from inflamed areas 3) Leakage of pure plasma followed by clotting fluids etc 4) infiltration of leukocytes 5) Fibrous tissue and healing

Question 29

What interleukin does cortisol reduce to block the development of a fever?

Answer 29

IL-1

Question 30

How does cortisol reduce the inflammatory pathway? (5)

Answer 30

1) Stabilizes lysosomal membranes so they cannot release enzymes 2) Decrease permeability of capillaries - less loss of plasma 3) Decrease migration of WBC and formation of inflammatory factors 4) Suppress immune system 5) Decrease fever by decreasing IL-1

Question 31

What stimulates the release of ACTH?

Answer 31

Corticotropin releasing factor (CRF)

Question 32

How is ACTH regulated?

Answer 32

Cortisol acts on both the hypothalamus to reduce CRF release as well as anterior pituitary to reduce ACTH release

Question 33

What changes (physical exam and blood work) would you see in hyperaldosteronism?

Answer 33

Hypokalemia, metabolic alkalosis, Increased ECF volume, slight hypernatremia, hypertension

Question 34

How do you test for hyperalosteronism?

Answer 34

Renin - should be low if patient has hyperaldosteronism (i.e. feedback loop is trashed)