Adrenal gland and HPA

Question 1

The adrenal medulla is innervated by what

Answer 1

sympathetic preganglionic efferent nerves

Question 2

True/False: adrenal medullary cells function as post ganglionic sympathetic “neurons”

Answer 2

true

Question 3

What are the three zones of the adrenal cortex and what do they produce

Answer 3

Zona glomerulosa: mineralcorticoids
Zona fasiculata: glucocorticoids
Zona reticularis: androgens

Question 4

The precursor for all adrenocortical steroids is ___

Answer 4

cholesterol

Question 5

What is the main product of the adrenal medulla

Answer 5

catecholamines

Question 6

What is the rate limiting step/essential enzyme in the synthesis of adrenocortical steroids?

Answer 6

cholesterol desmolase stimulated by ACTH

Question 7

Cholesterol uptake by the adrenal cortex is regulated by ____

Answer 7

ACTH

Question 8

True/False: cholesterol is stored inside adrenal cortex cells until it is required fro hormone synthesis

Answer 8

true

Question 9

True/False: adrenocortical steroids are stored in secretory vesicles until they are needed

Answer 9

false!! they are synthesized as needed

Question 10

what is the common precursor for all adrenocortical hormones?

Answer 10

pregnenolone

Question 11

The specialization of the zones of the adrenal cortex is conferred by _____

Answer 11

the enzymes present

Question 12

Mineralocorticoid secretion is controlled by what?

Answer 12

RAAS

Question 13

Glucocorticoid and androgen secretion are controlled by what?

Answer 13

HPA which is under classical negative feedback control

Question 14

What is the main method of action of steroid hormones?

Answer 14

they bind to intracellular receptors and act through transcription of DNA and synthesis of new proteins

Question 15

What is the physiologically most important mineralocorticoid?

Answer 15

aldostrone

Question 16

Aldostrone secretion is regulated by what?

Answer 16

extracellular fluid volume
changes in serum K+ levels

Question 17

True/False: ACTH is required fro aldostrone synthesis, but is of minor importance in the secretion rate

Answer 17

true

Question 18

True/False: K+ changes act indirectly on aldostrone producing cells

Answer 18

false, it DIRECTLY acts on aldostrone producing cells

Question 19

What are the immediate and slow onset effects of aldostrone

Answer 19

Immediate effect: prolongs the opening of Na+ channels in the apical membrane of the renal distal tubules and collecting ducts
Slow onset effect: increases synthesis of Na+ and K+ channels in the apical membrane and Na+/K+ pump in the basolateral membrane of the renal tubular epithelium

Question 20

How is aldostrone excreted?

Answer 20

it is conjugated in the liver and excreted in the urine and bile

Question 21

What is the overall effect of glucocorticoids in glucose metabolism

Answer 21

increases blood glucose concentration

Question 22

True/False: glucocorticoids have a prominent circadian variation

Answer 22

true

Question 23

True/False: nothing (besides drugs) can override the circadian rhythm of glucocorticoid secretion

Answer 23

false, stress can override this rhythm

Question 24

True/False: all nucleated cells have glucocorticoid receptors

Answer 24

true

Question 25

True/False: glucocorticoids increase gluconeogenesis, proteolysis, and lipolysis

Answer 25

true

Question 26

What is the effect of glucocorticoids on insulin sensitivity

Answer 26

they decrease it

Question 27

What is the overall effect of glucocorticoids on inflammatory and immune responses

Answer 27

they have a general inhibiting effect

Question 28

Glucocorticoids are rapidly released in response to what 4 major types of stress

Answer 28

trauma infection environmental temperature variations psychological stress

Question 29

You run pre op bloodwork on a 3yo cat and find everything WNL except the glucose, which is slightly elevated. Is this normal? why /why not

Answer 29

it can be normal due to stress. The psychological stress can cause the secretion of glucocorticoids which has a general effect of increasing blood glucose concentration

Question 30

Glucocorticoids will mobilize protein from all tissues except ____ for use in proteolysis

Answer 30

liver

Question 31

How do glucocorticoids have broadly immunosuppressive effects?

Answer 31

cortisol induces synthesis of lipocortin which inhibits phospholipase A2 which is responsible for prostaglandin and leukotriene production

Question 32

What 4 hormones/molecules require the presence of cortisol to be affective

Answer 32

insulin, glucagon, GH, and angiotensin II

Question 33

What are catecholamines synthesized from?

Answer 33

tyrosine

Question 34

what catecholamine is secreted in higher quantities

Answer 34

epinephrine

Question 35

Where are catecholamines inactivated

Answer 35

the liver and kidneys

Question 36

What are three important physiologic effects of catecholamines

Answer 36

-elevated plasma glucose -mobilization of fatty acids as a source of energy -redistribution of blood supply to preserve blood flow to heart and brain