Adrenal Physiology Flashcards Preview

Endocrinology > Adrenal Physiology > Flashcards

Flashcards in Adrenal Physiology Deck (24)
Loading flashcards...
1
Q

What does each section of adrenal secrete?

A

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

2
Q

Adrenocorticoids are synthesized from ____ by _____

A

Adrenocorticoids are synthesized from cholesterol by cytochrome P450

3
Q

What are steps

A

asdf

4
Q

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

A

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

5
Q

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

A

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

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

6
Q

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

A

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

7
Q

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

A

Function: Regulate pubarche
Stimulator: ACTH

8
Q

What are functions of NE/epinephrine (2)

A

Regulate CV effects

Regulate bronchial dilation

9
Q

What is mechanism of Aldosterone?

A

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
Q

What are stimulants of CRH? (2)

A

Circadian rhythm, physical stressors

11
Q

What are stimulants of ACTH (3)?

A

CRH, inflammation, arginine vasopressin

12
Q

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

A

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
Q

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

A

Circadian rhythm with pulsatility.

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

14
Q

What are cortisol actions?

Liver, skeletal muscle, adipose, Heart, vascular smooth muscle, immune, bone, medulla

A

Lots and lots…know list

15
Q

Explain cortisol-cortisone shunt

A
Mineralocorticoid receptor has higher affinity for cortisol than aldosterone
In kidney (aldosterone sensitive tissue), shunt cortisol to cortison
16
Q

Explain how cortisone is converted back to cortisol

A

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

17
Q

Explain pseudohyperaldosteronism and licorice

A

Licorice prevents inactivation of cortisol in kidney

Cortisol activates MCR–>hypertension and hypokalemia

18
Q

What are functions of DHEA and androstenedione?

A

DHEA: stimulates pubarche

Androstenedione: converted to testosterone and estrone in peripheral tissues

19
Q

Explain catecholamine synthesis

A

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

20
Q

What is rate limiting step of catecholamine synthesis?

A

Tyrosin to DOPA via tyrosine hydroxylation

21
Q

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

A

Cortisol upregulates PNMT enzyme which converts NE–>Epinephrine

22
Q

How much of catecholamines does medulla secrete?

A

20% NE

80%epinephrine

23
Q

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

A

Bind adrenergic receptors (a1/a2/ß1/ß2)

Too many locations and effects to list

24
Q

Describe fight or flight response (7)

A

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