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Physiology Exam 3 > Lecture 63-Adrenal Medulla And Cortex > Flashcards

Lecture 63-Adrenal Medulla And Cortex Flashcards

1
Q

Where are the adrenal glands located?

A

Retroperitoneal cavity above each kidney

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2
Q

What are the two separate structural/functional glands of the kidney?

A

Medulla and cortex

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3
Q

What does the adrenal cortex produce?

A

Mineralcorticoids, glucocorticoids, androgens

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4
Q

What does the adrenal medulla produce?

A

Epinephrine and norepinephrine

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5
Q

What receptors does epinephrine act on?

A

ALL alpha- and beta- adrenergic receptors

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6
Q

What receptors does noraepinephrine act on?

A

Alpha 1 & 2, beta-1 receptors

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7
Q

What do chromaffin cells secrete?

A

Catecholamines (epinephrine and norepinephrine)

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8
Q

What is the half-life of chromaffin cells?

A

2 minutes

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9
Q

Where is the adrenal medulla located?

A

In the inner zone of the gland and surrounded by the cortex

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10
Q

Where does the adrenal medulla receive input from? What is it considered?

A

Receives input from sympathetic nervous system via preganglionic fibers originating in the thoracic spinal cord

**considered a specialized sympathetic ganglion

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11
Q

Where is epinephrine stored? And when is it released?

A

Stored in granules, and released when activated by SNS

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12
Q

Why does cortisol reach the medulla in such high concentrations?

A

Because it is made in the cortex

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13
Q

What enzyme converted NE -> EPI under the influence of cortisol?

A

Phenylethanolamine-N-methyltransferase (PNMT)

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14
Q

What is the predominant catecholamine synethesized?

A

Epinephrine (80%)

NE (20%)

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15
Q

Where does all EPI originate from?

A

Adrenal medulla

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16
Q

Where does most NE originate from?

A

Sympathetic nerve terminals and brain

(Only small amount from adrenal medulla)

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17
Q

What is the target tissue of catecholamines?

A

Muscle cells and liver

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18
Q

Where does the most metabolism of catecholamines occur in?

A

Liver and kidneys

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19
Q

The regulation of catecholamine secretion is responsible for which response?

A

FIGHT OR FLIGHT

20
Q

What are the effects of catecholamines?

A

-increased heart rate, cardiac output, and blood pressure
-redistribution of blood towards skeletal muscle
-increased respiration
-increased blood glucose
-blood shunted AWAY from GIT
-increase lipolysis and possible gluconeogenesis

21
Q

What are the zones AND major hormones of each zone in the adrenal cortex?

A
  1. Zona glomerulosa
    A.) aldosterone
  2. Zona Fasciculata
    A.) cortisol (in humans, dogs, cats, horses, pigs, sheep, cattle)
    B.) corticosterone (in rat, mouse, rabbit)
  3. Zona reticularis
    A.) androgen precursors-> converted to testerogen and estrogen in peripheral
    B.) DHEA
    C.) Androsterone
22
Q

What is the precursors for all steroids?

A

Cholesterol

23
Q

What is the first step of steroid hormone production? Which enzyme plays a big role? Which zones contain this step?

A

Conversion of cholesterol to pregnenolone

Cholesterol Desmolase is the enzyme that makes this conversion possible !

All layers or zones contain this enzyme !!!!!!!!

24
Q

What does the direction of the hormone pathway depend on?

A

Presence/absence of enzymes to catalyze modifications

25
Q

Where is the main site of production for mineralcorticoids (such as aldosterone)?

A

Adrenal cortex: Zona glomerulosa

26
Q

What does the production of mineralcorticoids REQUIRE?

A

Aldosterone Synthase

ACTH to stimulate cholesterol desmolase

27
Q

Aldosterone is long OR short term regulation of blood pressure?

A

Long-term

28
Q

What type of pattern does aldosterone display?

A

Diurnal pattern

29
Q

What is the half life of aldosterone?

A

20 minutes

30
Q

How does the primary regulation of aldosterone occur? (2)

A

Via changes in ECF volume via renin angiotensin II-aldosterone system AND changes in blood pressure

31
Q

How is aldosterone transported in blood?

A

Aldosterone-binding globulin, transcortin, albumin

32
Q

What stimulates synthesis of aldosterone? WHat is considered the mediator in aldosterone secretion?

A

Angiotensin II

33
Q

What are the two things that the renin-angiotensin II-aldosterone system DECREASES? What is one thing this system INCREASES? What is the ultimate end goal of this system?

A

Decreases = ECF volume, renal blood perfusion pressure

Increases= renin secretion by kidney

End goal = stimulates Na reabsorption by kidney to restore ECF volume

34
Q

When regulating aldosterone secretion there is an increase in blood K+ concentration. This results in deporliazation of adrenal cells to open which channel? The opening of this channel stimulates secretion of what? Which ultimately results in excretion of what?

A

Depolarization adrenal cells = opening Ca channels = stimulate aldosterone secretion = increases K+ excretion in kidneys

35
Q

Where are glucocorticoids (cortisol) produced?

A

Adrenal cortex: Zona fasciculata

36
Q

What is required to produce glucocorticoids?

A

ACTH to stimulate cholesterol desmolase

37
Q

What is the half life of cortisol?

A

60-90 minutes

38
Q

What axis is cortisol regulated by?

A

Hypothalamic-pituitary-adrenal axis

39
Q

How is cortisol transported in blood?

A

By transcortin

40
Q

What is cortisol metabolized by? Where is it excreted?

A

Metabolized by the liver

Excreted in urine using glucuronides

41
Q

What are two factors that influence ACTH secretion?

A

Stimulators and inhibitors

42
Q

What are examples of stimulators?

A

Stress, low cortisol, ADH

43
Q

What are examples of inhibitors?

A

High cortisol, exogenous steroids, somatostatin, dopamine

44
Q

What two things inhibit CRH release?

A

Cortisol and ACTH

45
Q

ACTH has a ___ loop feedback to inhibit CRH release. Cortisol has a ____ loop feedback to block CRH release.

A

ACTH has short loop feedback

Cortisol has long loop feedback

46
Q

What does administration of exogenous corticosteroids create? And then result in?

A

Creates negative feedback

Resulting in adrenal gland atrophy

Physiology Exam 3 (17 decks)

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