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Flashcards in Adrenal Physiology Deck (24):
1

What does each section of adrenal secrete?

G: Aldosterone
F: Glucocorticoids (cortisol)
R: DHEA
Medulla: NE/Epinephrine

2

Adrenocorticoids are synthesized from ____ by _____

Adrenocorticoids are synthesized from cholesterol by cytochrome P450

3

What are steps

asdf

4

Which hormone can only be made in one area of adrenal gland? Why?

Aldosterone can only be made in zona glomerulosa because only those cells have aldosterone synthetase

5

What is the function of Aldosterone? (2) What are stimulants for Aldosterone release? (3)

Function of aldosterone: regulate blood volume, salt/water homeostasis

Stimulators: Angiotensin II, [K], ACTH (to lesser degree)

6

What is the function of cortisol? (2) What are stimulants for cortisol release? (2)

Functions of cortisol: energy balance, CV/metabolic/immune homeostasis
Stimulators: ACTH, Arginine vasopressin (lesser stimulus)

7

What is function of androgens? (1) What is stimulant for androgen release? (1)

Function: Regulate pubarche
Stimulator: ACTH

8

What are functions of NE/epinephrine (2)

Regulate CV effects
Regulate bronchial dilation

9

What is mechanism of Aldosterone?

Aldosterone binds mineralocorticoid receptor in distal collecting duct of principal cell
Moves to nucleus to stimulate transcription of Na/K channels-->More Na reabsorption, K/H+ secretion

10

What are stimulants of CRH? (2)

Circadian rhythm, physical stressors

11

What are stimulants of ACTH (3)?

CRH, inflammation, arginine vasopressin

12

What are functions of ACTH? (2) Explain its melanogenic properties

Functions: Increase LDL receptors to bring in more cholesterol as precursor for steroidogenesis
Activate CYP11A1 enzyme for steroid cleavage

Functions as melanocortin by activating melanocortin 1 receptor on melanocyte (leads to skin pigmentation)

13

Explain cortisol secretion pattern. When is it highest/lowest?

Circadian rhythm with pulsatility.

Highest 6-8 hours after sleeping and declines after awakening
Lowest at midnight

14

What are cortisol actions?
Liver, skeletal muscle, adipose, Heart, vascular smooth muscle, immune, bone, medulla

Lots and lots...know list

15

Explain cortisol-cortisone shunt

Mineralocorticoid receptor has higher affinity for cortisol than aldosterone
In kidney (aldosterone sensitive tissue), shunt cortisol to cortison

16

Explain how cortisone is converted back to cortisol

Cortisone in liver (GCR rich tissue) is converted back to cortisol

17

Explain pseudohyperaldosteronism and licorice

Licorice prevents inactivation of cortisol in kidney
Cortisol activates MCR-->hypertension and hypokalemia

18

What are functions of DHEA and androstenedione?

DHEA: stimulates pubarche

Androstenedione: converted to testosterone and estrone in peripheral tissues

19

Explain catecholamine synthesis

Tyrosine enters chromatin cells and is converted by TH to dopa. Dopa then converted to NE/epinephrine

20

What is rate limiting step of catecholamine synthesis?

Tyrosin to DOPA via tyrosine hydroxylation

21

What promotes NE to epinephrine conversion? How does it work?

Cortisol upregulates PNMT enzyme which converts NE-->Epinephrine

22

How much of catecholamines does medulla secrete?

20% NE
80%epinephrine

23

What do catecholamines bind? What are the locations and effects?

Bind adrenergic receptors (a1/a2/ß1/ß2)
Too many locations and effects to list

24

Describe fight or flight response (7)

Mobilize fuels, redistribute blood flow, decrease urinary output/GI, increase HR/BP, increase activity of sweat glands, increase ventilation, dilation of pupils