Exam 5: Adrenal Physiology

Question 1

What hormone comes from zona fasciculata?

Answer 1

Cortisol

Question 2

What hormone comes from zona glomerulosa?

Answer 2

Aldosterone

Question 3

What hormone comes from zona reticularis?

Answer 3

Androstenedione

Question 4

What are examples of adrenocortical steroids/corticosteroids?

Answer 4

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

Question 5

Which corticosteroid has the biggest physiologic effect?

Answer 5

Aldosterone

Question 6

What is the adrenal gland composed of?

Answer 6

Adrenal cortex

Adrenal medulla

Question 7

What comes from the adrenal cortex?

Answer 7

Steroid hormones

Question 8

What occurs in the adrenal medulla?

Answer 8

Catecholamine synthesis

Question 9

What is catecholamine released into?

Answer 9

Blood

Question 10

What is catecholamine responsible for?

Answer 10

Fight or flight

Question 11

What is the catecholamine in cats?

Answer 11

Norepinephrine

Question 12

What is the catecholamine in digs and humans?

Answer 12

Epinephrine

Question 13

What does catecholamine cause?

Answer 13

Increase in metabolic rate

Increase in BP, cardiac contractility, and myocardial excitability

Question 14

What kind of regulation is the adrenal medulla under?

Answer 14

SNS

Question 15

What are the layers of the adrenal cortex?

Answer 15

Glomerulosa
Fasciculata
Reticularis

Question 16

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

Answer 16

Aldosterone synthase

Mineralocorticoids

Question 17

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

Answer 17

17α-hydroxylase/P450c17

Glucocorticoids, sex hormones

Question 18

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

Answer 18

17α-hydroxylase/P450c17

Glucocorticoids, sex hormones

Question 19

What is the half-life of cortisol?

Answer 19

Less than 2 hours

Question 20

What is the half-life of aldosterone?

Answer 20

About 20 minutes

Question 21

Which steroids are active?

Answer 21

Those that are free/unbound

Question 22

Where does cortisol have receptors?

Answer 22

In most cells

Question 23

What are the cellular functions of cortisol?

Answer 23

Catabolic
Anti-inflammatory
Immunosuppressive
Anti-stress

Question 24

What are the catabolic actions of cortisol?

Answer 24

Stimulate gluconeogenesis
Anti-insulin
Breaks down protein

Question 25

Describe the catabolic effects of cortisol on carbohydrates

Answer 25

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

Question 26

Describe the catabolic effects of cortisol on lipids

Answer 26

Mobilizes fatty acids | Redistribution

Question 27

Describe the catabolic effects of cortisol on proteins

Answer 27

Inhibits cellular uptake of amino acids Stimulates gluconeogenesis Muscle breakdown*

Question 28

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

Answer 28

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

Question 29

What happens to CRH when ACTH increases?

Answer 29

Decreases

Question 30

What happens to CRH when cortisol increases?

Answer 30

Descreases

Question 31

What happens to ACTH when cortisol increases?

Answer 31

Decreases

Question 32

What is the release of aldosterone stimulated by?

Answer 32

Deceased blood volume Decreased Na Increased K

Question 33

What is the primary function of aldosterone?

Answer 33

Increase Na, Cl, and water resorption | Increase K and H excretion

Question 34

What is the site of action of aldosterone?

Answer 34

Principal cells of distal tubules and collecting ducts

Question 35

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

Answer 35

Increase activity of basolateral Na/K ATPse | Increase transcription of luminal Na channels

Question 36

What regulates aldosterone?

Answer 36

Renin-angiotensin-aldosterone system (RAAS)

Question 37

Describe renin

Answer 37

Released from afferent arteriole | Response to hypovolemia

Question 38

Describe angiotensin

Answer 38

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

Question 39

What is the RAAS system directly stimualted by?

Answer 39

Increased K+