Adrenal Physiology

Question 1

Where are minrealocorticoids produced

Answer 1

Zona glmoerulosa of the adrenal gland (cortex)

Question 2

Where are glucocorticoids produced

Answer 2

Zona fasiculata of the adrenal gland (cortex)

Question 3

Where are androgens produced

Answer 3

Zona reticularis of the adrenal gland (cortex)

Question 4

Where in the adrenal gland are catechooamines produced

Answer 4

The medulla

Question 5

Effect of aldosterone (mineralocorticoid) in the body

Answer 5

• retention of Na+ at the DCT
• loss of K+
• loss of H+ in the DCT

Question 6

What is the release of aldosterone (mineralocorticoid) mediated by

Answer 6

1. RAAS system (angiotensin II as a result of the stimulation by juxtaglmoerular cells of the kidneys)
2. ACTH release
3. ↑ in K+ in plasma

Question 7

Glucocorticoids example

Answer 7

Cortisol

Question 8

What is the release of Cortisol (glucocorticoid) mediated by?

Answer 8

ACTH (adrenocorticotrophic hormone) stimulation of the zona fasiculata
ACTH released from the anterior pituitary
It’s release stimulated by CRH (corticotrophin releasing hormone)

Question 9

What is thr effect of Cortisol (glucocorticoid) in the body?
Metabolism
Stress resistance
Suppression of immune system

Answer 9

• gluconeogenesis
• storage of glucose
  -fat metabolism
  -protein breakdown
  BASICALLY INCREASES THE AMOUNT OF GLUCOSE CIRCULATING IN THE BODY

Cardiovascular stimulation (cortisol necessary for catecholamines to work)

Inhibition of inflammation and immunity

Question 10

What events stimulate cortisol (glucocorticoid) release?

Answer 10

Stress

Normal circadian release (diurnal release, greatest in th mornings)

Question 11

Examples of stress events which cause release of cortisol

Answer 11

Blood loss
Infection 
Trauma 
HYPOGLYCAEMIA
Exercise 
Anxiety

Question 12

What stimulates the medulla of the adrenal gland?

Answer 12

Sympathetic nervous stimulation of the preganglionic nerves

Question 13

What cells are responsible for the storage of catecholamines in the adrenal medulla?

Answer 13

Chromaffin cells

Question 14

Effects of catecholamines released from the adrenal medulla on the body

Answer 14

↑ metabolism and heat production 
↑ gluconeogenesis 
↓ uptake of glucose in GI 
↑ fat and protein breakdown 
↑ glycogenolysis 

INCREASE IN BLOOD GLUCOSE

Question 15

What chemicals are secreted by the chromaffin cells of the adrenal medulla

Answer 15

Adrenaline 80%

Noradrenaline 20%

Question 16

How do catecholamines stimulate cell change (simple)

Answer 16

They attach to adrenergic receptors on the surfaces of cells

Releases a second messenger cAMP

cAMP causes the important functional proteins to activate, causing cell change

Question 17

What is the ultimate aim of catecholamines and cortisol when released?

Answer 17

INCREASE GLUCOSE STORES 
Through 
- gluconeogenesis 
- protein and fat breakdown 
- glycogen storage

Question 18

What occurs when there is an pathology in the adrenal medulla causing ↑ release of catecholamines

Answer 18

Phaeochromocytoma

• hypertension
• hyperglycaemia

(Effects of adrenaline)