Wk 9

Question 1

What are the two regions of the adrenal gland?

Answer 1

1. Adrenal cortex - outer region
2. Adrenal medulla - inner region

Question 2

What are the three zones of the adrenal cortex?

Answer 2

1. Zona glomerulosa (outer layer) - mineralocorticoids (salt)
2. Zona fasciculata (middle layer) - glucocorticoids (sweet)
3. Zona reticularis (inner layer) - androgens (sexy)

Question 3

What are the 2 major types of steroid hormones secreted?

Answer 3

C19 and C21

Question 4

What are the types of mineralocorticoids (salt) hormones?

Answer 4

• Aldosterone
• Deoxycorticosterone

Question 5

What are the types of glucocorticoids (sweet) hormones?

Answer 5

• Cortisol
• Corticosterone

Question 6

What are the types of androgen (sexy) hormones?

Answer 6

• DHEA
• Androstenedione

Question 7

Which zone converts corticosterone to aldosterone?

Answer 7

Zona glomerulosa (only zone that contains aldosterone synthase).

Question 8

What is the precursor of adrenal steroid hormones?

Answer 8

Cholesterol

Question 9

What is biosynthesis pathway for zona glomerulosa?

Answer 9

Cholesterol –> Pregnenolone –> Progesterone –> Aldosterone

Question 10

What is biosynthesis pathway for zona fasciculata?

Answer 10

Cholesterol –> Pregnenolone –> Progesterone –> Cortisol

Question 11

What is biosynthesis pathway for zona reticularis?

Answer 11

Cholesterol –> Pregnenolone –> 17(OH) Pregnenolone –> Androstenedione

Question 12

Where does cortisol act on primarily?

Answer 12

• Liver
• Skeletal muscle
• Adipose tissue

Question 13

What are the effects of cortisol on carbohydrate metabolism?

Answer 13

• hyperglycemic hormone
• increases blood glucose via stimulating gluconeogenesis (liver)

Question 14

What are the effects of cortisol on protein metabolism?

Answer 14

• increases proteins in liver ONLY
• reduces protein stores in rest of body
• increases blood AA

Question 15

What are the effects of cortisol on fat metabolism?

Answer 15

• increases lipolysis (fat breakdown)
• utilises glycerol & fatty acids from lipolysis and redistributes when there is excess

Question 16

How is cortisol transported in the blood?

Answer 16

Corticosteroid-binding globulin (CBG)

Question 17

What triggers the secretion of cortisol?

Answer 17

All forms of stress:
- trauma
- infection
- illness
- temperature change
- mental stress

Question 18

How is cortisol regulated?

Answer 18

Hypothalamic-pituitary-adrenal axis
CRH - hypothalamus
ACTH - pituitary

*negative feedback loop

Question 19

What is the effect of aldosterone in the kidney?

Answer 19

Regulation of electrolyte (mineral) conc. in extracellular fluids, especially conc. of sodium and potassium.

Question 20

What are the regulators of aldosterone secretion?

Answer 20

1. Renin-angiotensin system (angiotensin II stimulates)
2. Potassium (increase = stimulates)
3. Sodium (increase = inhibits)
4. ACTH (increase = stimulates)
5. Atrial Natriuretic Peptide (ANP) (blocks/inhibits secretion)

Question 21

What is the adrenal medulla structure?

Answer 21

Modified sympathetic ganglion (preganglionic –> gland)
*Contains chromaffin

Question 22

What are the three catecholamines secreted from the adrenal medulla?

Answer 22

1. Epinephrine
2. Norepinephrine
3. Dopamine

Question 23

What are catecholamines synthesised from?

Answer 23

Amino acid tyrosine

Question 24

What are the actions of the catecholamines secreted on the cardiovascular system?

Answer 24

• increase cardiac output
• increase venous return (blood flow into heart)

Question 25

What are the actions of the catecholamines secreted on blood glucose?

Answer 25

- increase blood flow to skeletal muscle - increase blood glucagon/insulin ratio (alpha increase glucagon, beta decrease insulin) - increase glycogenolysis (breakdown of glycogen) - increase gluconeogenesis (formation of glucose from non-carbohydrates)

Question 26

What is the name of the syndrome with hypercortisolism?

Answer 26

Cushing's syndrome

Question 27

What are the types of Cushing's syndrome?

Answer 27

1. Pituitary 2. Adrenal 3. Ectopic

Question 28

What is Pituitary Cushing's Syndrome?

Answer 28

- Pituitary adenoma - Elevated ACTH levels

Question 29

What is Adrenal Cushing's Syndrome?

Answer 29

- Disease in one/both adrenal glands - Low ACTH levels

Question 30

What is Ectopic Cushing's Syndrome?

Answer 30

- ACTH secretion from anywhere other than the anterior pituitary - Increased plasma ACTH

Question 31

What are symptoms of Cushing's Disease?

Answer 31

- red/moon face - central/truncal obesity - buffalo hump (shoulder)

Question 32

What are the signs of Addison's Disease?

Answer 32

- primary adrenal insufficiency - extremely low mineralocorticoids and glucocorticoids - due to TB or autoimmune chronic destruction of gland

Question 33

What are the symptoms of Addison's Disease?

Answer 33

- hyperpigmentation - hyperkalemia (increase K+) - acidosis (increase blood acid)

Question 34

Why does Addison's Disease cause hyperpigmentation?

Answer 34

Elevated levels of ACTH can compete for binding of MC1R in melanocytes.

Question 35

What is congenital adrenal hyperplasia?

Answer 35

- deficiency of the enzyme 21-hydroxylase - impaired cortisol = increased ACTH - high ACTH = drive adrenal androgen production ( by zona reticularis)

Question 36

What is the dexamethasone suppression test?

Answer 36

Laboratory test used to confirm Cushing's Syndrome. *Used to differentiate Cushing's Disease from Ectopic Cushing's Syndrome.