Adrenal Glands

Question 1

where are adrenal glands located

Answer 1

glands found above each kidney

Question 2

how many glands in the adrenal glands

Answer 2

2, outer cortex and inner medulla

Question 3

what is the outer cortex

Answer 3

secretes corticosteroids

hormones regulate:- electrolyte balance
blood glucose
protein turnover
survival under stress
tissue responses to injury/infection

Question 4

what is the inner medulla

Answer 4

secretes adrenaline

involved in the stress response

Question 5

how is blood supplied to the adrenal gland

Answer 5

via 3 arteries

1. superior superenal arteries: supplied via the inferior phrenic arteries.
2. middle superenal arteries: supplied directly from the abdominal aorta.
3. inferior superenal arteries: supplied via the renal artery.

Question 6

what hormones does the adrenal cortex release

Answer 6

corticosteroids

1. Zona Glomerulosa
2. Zona fasciculata
3. Zona reticularis

Question 7

what is Zona Glomerulosa

Answer 7

mineralocorticoids (aldosterone)

Question 8

what is Zona fasciculata

Answer 8

glucocorticoids (cortisol, cortisone)

Question 9

what is Zona reticularis

Answer 9

gonadocorticoids (androgens)

Question 10

what does Zona Reticularis synthesise

Answer 10

• mainly androgens (testosterone)

- some estrogens (oestradiol)

Question 11

what is adrenal hyperplasia

Answer 11

• androgen secretion in female = virilisation

- oestogen secretion in male = feminisation

Question 12

what is mineralocorticoids (outer layer makes these)

Answer 12

Hormones regulating plasma electrolyte concentrations (& hence blood volume)

e.g. Aldosterone

Question 13

what is aldosterone

Answer 13

acts mainly on convoluted tubules of kidney

maintains Na+ balance by reducing the excretion of sodium

prevents hyperkalaemia (high potassium)

Question 14

Aldosterone acts on sodium reabsorption in the kidney

where does this occur

Answer 14

65% of reabsorption occurs in proximal and distal tubules

25% in loops of Henle

Question 15

when aldosterone levels are high

Answer 15

all remaining Na+ is actively reabsorbed

Question 16

water follows sodium if

Answer 16

tubule permeability has been increased with ADH

Question 17

aldosterone overall movement of ions

Answer 17

Na+ to blood
K+ to urine
H2O, Cl- to tubule cell

Question 18

what are the main regulators of aldosterone secretion

Answer 18

Low plasma sodium and high potassium (directly influences zona glomerulosa cells)

(low Na+ or high K+ stimulates release)

renin-angiotensin system

Question 19

what is the secondary regulation of aldosterone secretion

Answer 19

ACTH causes small increases of aldosterone during stress

Atrial natriuretic peptide (ANP) inhibits secretion from zona glomerulosa

Question 20

other hormones that affect sodium balance

Answer 20

Oestrogens (before ovulation)

• enhance Na reabsorption by renal tubules
• may cause water retention during the menstrual cycle
• responsible for edema during pregnancy

Progesterone (after ovulation)

• decreases sodium reabsorption
• acts as a diuretic, promoting sodium and water loss

Question 21

what can go wrong with aldosterone

Answer 21

hypersecretion and hyposecretion

Question 22

hypersecretion of aldosterone

Answer 22

hypersecretion of aldosterone causes edema (ionic changes), hypertension (Na+ and volume changes), and alkylosis (HCO3- reabsorption)

Question 23

hyposecretion of aldosterone

Answer 23

hypotension (Blood Na+ & volume changes)

Weakness (ion changes)

Question 24

what is the adrenal medulla

Answer 24

Chromaffin cells:
- secrete catecholamines: adrenaline (80%) and noradrenaline (20%)

these hormones:
Increase blood glucose
Increase heart rate and force
Divert blood from GI tract to brain, heart and skeletal muscle
Similar effects to sympathetic nervous system

Are 50% bound to plasma proteins