Exam 5: Adrenal Physiology Flashcards Preview

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Flashcards in Exam 5: Adrenal Physiology Deck (39)
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1
Q

What hormone comes from zona fasciculata?

A

Cortisol

2
Q

What hormone comes from zona glomerulosa?

A

Aldosterone

3
Q

What hormone comes from zona reticularis?

A

Androstenedione

4
Q

What are examples of adrenocortical steroids/corticosteroids?

A
Glucocorticoids (cortisol)
Mineralocorticoids (aldosterone)
Sex steroids (progesterones, androgens, estrogens)
5
Q

Which corticosteroid has the biggest physiologic effect?

A

Aldosterone

6
Q

What is the adrenal gland composed of?

A

Adrenal cortex

Adrenal medulla

7
Q

What comes from the adrenal cortex?

A

Steroid hormones

8
Q

What occurs in the adrenal medulla?

A

Catecholamine synthesis

9
Q

What is catecholamine released into?

A

Blood

10
Q

What is catecholamine responsible for?

A

Fight or flight

11
Q

What is the catecholamine in cats?

A

Norepinephrine

12
Q

What is the catecholamine in digs and humans?

A

Epinephrine

13
Q

What does catecholamine cause?

A

Increase in metabolic rate

Increase in BP, cardiac contractility, and myocardial excitability

14
Q

What kind of regulation is the adrenal medulla under?

A

SNS

15
Q

What are the layers of the adrenal cortex?

A

Glomerulosa
Fasciculata
Reticularis

16
Q

What is the specific enzyme of the glomerulosa? What is the product?

A

Aldosterone synthase

Mineralocorticoids

17
Q

What is the specific enzyme of the faciculata? What is the product?

A

17α-hydroxylase/P450c17

Glucocorticoids, sex hormones

18
Q

What is the specific enzyme of the reticularis? What is the product?

A

17α-hydroxylase/P450c17

Glucocorticoids, sex hormones

19
Q

What is the half-life of cortisol?

A

Less than 2 hours

20
Q

What is the half-life of aldosterone?

A

About 20 minutes

21
Q

Which steroids are active?

A

Those that are free/unbound

22
Q

Where does cortisol have receptors?

A

In most cells

23
Q

What are the cellular functions of cortisol?

A

Catabolic
Anti-inflammatory
Immunosuppressive
Anti-stress

24
Q

What are the catabolic actions of cortisol?

A

Stimulate gluconeogenesis
Anti-insulin
Breaks down protein

25
Q

Describe the catabolic effects of cortisol on carbohydrates

A

Stimulates hepatic gluconeogenesis*
Inhibits effects of insulin
Fight or flight
Protects from hypoglycemia

26
Q

Describe the catabolic effects of cortisol on lipids

A

Mobilizes fatty acids

Redistribution

27
Q

Describe the catabolic effects of cortisol on proteins

A

Inhibits cellular uptake of amino acids
Stimulates gluconeogenesis
Muscle breakdown*

28
Q

Describe what happens with stress in a normal dog to synthesize cortisol

A

An increase in stress causes and increase in CRH from the hypothalamus. This leads to an increase of ACTH from the pituitary, which leads to an increase in cortisol from the adrenal gland

29
Q

What happens to CRH when ACTH increases?

A

Decreases

30
Q

What happens to CRH when cortisol increases?

A

Descreases

31
Q

What happens to ACTH when cortisol increases?

A

Decreases

32
Q

What is the release of aldosterone stimulated by?

A

Deceased blood volume
Decreased Na
Increased K

33
Q

What is the primary function of aldosterone?

A

Increase Na, Cl, and water resorption

Increase K and H excretion

34
Q

What is the site of action of aldosterone?

A

Principal cells of distal tubules and collecting ducts

35
Q

What does aldosterone do to the principal cells of distal tubules and collecting ducts?

A

Increase activity of basolateral Na/K ATPse

Increase transcription of luminal Na channels

36
Q

What regulates aldosterone?

A

Renin-angiotensin-aldosterone system (RAAS)

37
Q

Describe renin

A

Released from afferent arteriole

Response to hypovolemia

38
Q

Describe angiotensin

A

Renin converts angiotensinogen to angiotensin
AT converted to ATII by angiotensin converting enzyme in lungs
ATII stimulates aldosterone synthesis

39
Q

What is the RAAS system directly stimualted by?

A

Increased K+

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