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OSSF 2 > Exam 3- Adrenal Cortex and HPA Axis Adrenal Medulla > Flashcards

Exam 3- Adrenal Cortex and HPA Axis Adrenal Medulla Flashcards

1
Q

how is the inner portion of the adrenal glands innervated?

A

sympathetic preganglionic efferent nerves from hypothalamus

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2
Q

what does the adrenal cortex produce?

A

steroid hormones

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3
Q

what does the adrenal medulla produce?

A

catecholamines

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4
Q

what does the zona glomerulosa (outermost layer) produce?

A

mineralocorticoids

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5
Q

what does the zona fasciculata (middle layer) produce?

A

glucocorticoids

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6
Q

what does the zona reticularis (innermost layer) produce?

A

androgens

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7
Q

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

A

ACTH

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8
Q

what enzyme is important in adrenocortical hormone synthesis?

A

cholesterol desmolase: common first step in all adrenocortical hormone synthesis

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9
Q

what stimulates cholesterol desmolase?

A

ACTH, also dependent upon

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10
Q

what regulates glucocorticoid and androgen secretion?

A

hypothalamic-pituitary axis; negative feedback

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11
Q

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

A

mineralocorticoid secretion

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12
Q

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

A

false: lipid-soluble so no intracellular stores

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13
Q

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

A

extracellular fluid volume
serum (extracellular) K+ levels

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14
Q

how does potassium affect aldosterone secretion?

A

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

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15
Q

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

A

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

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16
Q

how do glucocorticoids affect glucose levels in blood?

A

increase them: catabolic and diabetogenic

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17
Q

true/false: all nucleated cells have glucocorticoid receptors

A

true

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18
Q

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

A

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

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19
Q

are glucocorticoids immunosuppressive?

A

yes

20
Q

how is cortisol immunosuppressive?

A

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

21
Q

do some other hormones need glucocorticoids to be effective themselves?

A

yes

22
Q

from what are catecholamines synthesized?

A

tyrosine

23
Q

what are the physiological effects of catecholamines?

A

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

24
Q

where are the adrenal glands located?

A

retroperitoneal
craniomedial to corresponding kidney
against roof of abdomen

25
Q

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

A

medulla

26
Q

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

A

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

27
Q

true/false: cholesterol is not stored inside the cell

A

false: is stored until it is required

28
Q

what is the common precursor for all adrenocortical hormones?

A

pregnenolone

29
Q

how is pregnenolone formed?

A

cholesterol desmolase converts cholesterol into it

30
Q

what is a mineralocorticoid?

A

aldosterone

31
Q

what are some glucocorticoids?

A

cortisol
corticosterone

32
Q

What does corticotropin releasing hormone stimulate?

A

ACTH

33
Q

how do adrenocortical hormones act?

A

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

34
Q

what are two specific transport proteins for adrenocortical hormones?

A

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

35
Q

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

A

albumin and prealbumin
transport steroid hormones

36
Q

how does angiotensin II stimulate aldosterone synthesis?

A

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

37
Q

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

A

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

38
Q

does an increase or decrease in potassium stimulate aldosterone secretion?

A

increase

39
Q

how is aldosterone metabolized and excreted?

A

conjugated to glucuronide in liver
excreted in urine and bile

40
Q

what can prolonged stress result in in the adrenal cortex?

A

chronically elevated ACTH and tropic effect on adrenal cortex

41
Q

what types of stress can lead to glucocorticoids being released?

A

trauma
infection
environmental temperature variations
psychological stress

42
Q

how do glucocorticoids raise blood glucose levels?

A

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

43
Q

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

A

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

44
Q

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

A

epinephrine

45
Q

what do the effects of epinephrine and norepinephrine depend on?

A

density of receptor subtypes and concentration of hormones

46
Q

what stimulates the adrenal medulla to release catecholamines?

A

acetylcholine from sympathetic preganglionic nerve endings

47
Q

what is the primary benefit of glucocorticoids?

A

ability to increase blood glucose

OSSF 2 (19 decks)

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