Exam 3- Adrenal Cortex and HPA Axis Adrenal Medulla

Question 1

how is the inner portion of the adrenal glands innervated?

Answer 1

sympathetic preganglionic efferent nerves from hypothalamus

Question 2

what does the adrenal cortex produce?

Answer 2

steroid hormones

Question 3

what does the adrenal medulla produce?

Answer 3

catecholamines

Question 4

what does the zona glomerulosa (outermost layer) produce?

Answer 4

mineralocorticoids

Question 5

what does the zona fasciculata (middle layer) produce?

Answer 5

glucocorticoids

Question 6

what does the zona reticularis (innermost layer) produce?

Answer 6

androgens

Question 7

what mediates uptake of LDL-cholesterol complex by adrenocortical cells?

Answer 7

ACTH

Question 8

what enzyme is important in adrenocortical hormone synthesis?

Answer 8

cholesterol desmolase: common first step in all adrenocortical hormone synthesis

Question 9

what stimulates cholesterol desmolase?

Answer 9

ACTH, also dependent upon

Question 10

what regulates glucocorticoid and androgen secretion?

Answer 10

hypothalamic-pituitary axis; negative feedback

Question 11

what hormone secretion does the renin-angiotensin-aldosterone system control?

Answer 11

mineralocorticoid secretion

Question 12

true/false: adrenocortical hormones are stored in granules so they are ready when they are needed

Answer 12

false: lipid-soluble so no intracellular stores

Question 13

secretion of mineralocorticoids (aldosterone) is regulated by changes in ____________________________ and in _____________________

Answer 13

extracellular fluid volume
serum (extracellular) K+ levels

Question 14

how does potassium affect aldosterone secretion?

Answer 14

acts directly on aldosterone-producing cells: higher K+ depolarizes cell membrane, leading to increase in intracellular calcium, stimulating cholesterol desmolase and aldosterone synthase

Question 15

aldosterone has immediate and slow-onset effects in the kidney. these are:

Answer 15

prolongs opening time of Na+ channels: immediate
increases synthesis of Na+ channels and K+ channels: slow-onset

Question 16

how do glucocorticoids affect glucose levels in blood?

Answer 16

increase them: catabolic and diabetogenic

Question 17

true/false: all nucleated cells have glucocorticoid receptors

Answer 17

true

Question 18

how do glucocorticoids affect carbohydrate, lipid, and protein metabolism?

Answer 18

increases carbohydrate metabolism
mobilizes protein from tissues- not liver
mobilizes fatty acids

Question 19

are glucocorticoids immunosuppressive?

Answer 19

yes

Question 20

how is cortisol immunosuppressive?

Answer 20

induces synthesis lipocortin, which inhibits phospholipase A2: prostaglandin and leukotriene synthesis suppressed
inhibits production interleukin-2 and proliferation T cells
inhibits release histamine and serotonin from mast cells and platelets
overall suppression adaptive and innate immune responses

Question 21

do some other hormones need glucocorticoids to be effective themselves?

Answer 21

yes

Question 22

from what are catecholamines synthesized?

Answer 22

tyrosine

Question 23

what are the physiological effects of catecholamines?

Answer 23

elevated plasma glucose
mobilization fatty acids as source of energy
increased cardiac output
redistribution of blood supply

Question 24

where are the adrenal glands located?

Answer 24

retroperitoneal
craniomedial to corresponding kidney
against roof of abdomen

Question 25

what part of the adrenal gland functions as part of the autonomic nervous system?

Answer 25

medulla

Question 26

what is the basis of specialization in each zone of the adrenal cortex?

Answer 26

presence/absence of enzymes that catalyze various modifications of the steroid nucleus

Question 27

true/false: cholesterol is not stored inside the cell

Answer 27

false: is stored until it is required

Question 28

what is the common precursor for all adrenocortical hormones?

Answer 28

pregnenolone

Question 29

how is pregnenolone formed?

Answer 29

cholesterol desmolase converts cholesterol into it

Question 30

what is a mineralocorticoid?

Answer 30

aldosterone

Question 31

what are some glucocorticoids?

Answer 31

cortisol corticosterone

Question 32

What does corticotropin releasing hormone stimulate?

Answer 32

ACTH

Question 33

how do adrenocortical hormones act?

Answer 33

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

Question 34

what are two specific transport proteins for adrenocortical hormones?

Answer 34

corticosteroid-binding globulin (CBG) sex hormone-binding globulin (SHBG)

Question 35

what are two non-specific transport proteins for adrenocortical hormones?

Answer 35

albumin and prealbumin transport steroid hormones

Question 36

how does angiotensin II stimulate aldosterone synthesis?

Answer 36

AT1 receptors on zona glomerulosa cells Ca++ influx stimulation cholesterol desmolase and aldosterone synthase

Question 37

what stimulates the renin-angiotensin-aldosterone pathway and what does it do?

Answer 37

decrease in perfusion pressure to kidney sodium retention at expense of potassium loss

Question 38

does an increase or decrease in potassium stimulate aldosterone secretion?

Answer 38

increase

Question 39

how is aldosterone metabolized and excreted?

Answer 39

conjugated to glucuronide in liver excreted in urine and bile

Question 40

what can prolonged stress result in in the adrenal cortex?

Answer 40

chronically elevated ACTH and tropic effect on adrenal cortex

Question 41

what types of stress can lead to glucocorticoids being released?

Answer 41

trauma infection environmental temperature variations psychological stress

Question 42

how do glucocorticoids raise blood glucose levels?

Answer 42

stimulate hepatic gluconeogenesis decrease glucose utilization and insulin sensitivity of tissues mobilize amino acids from muscle for hepatic gluconeogenesis

Question 43

true/false: glucocorticoids have a permissive role with keeping tissues responsive to other hormones

Answer 43

true: alpha 1 adrenergic receptors upregulated insulin, glucagon, growth hormone, angiotensin II need cortisol

Question 44

what catecholamine is secreted at the highest rate from the adrenal medulla?

Answer 44

epinephrine

Question 45

what do the effects of epinephrine and norepinephrine depend on?

Answer 45

density of receptor subtypes and concentration of hormones

Question 46

what stimulates the adrenal medulla to release catecholamines?

Answer 46

acetylcholine from sympathetic preganglionic nerve endings

Question 47

what is the primary benefit of glucocorticoids?

Answer 47

ability to increase blood glucose