Physiology Of The Adrenal Gland(Physiology)

Question 1

The steroid hormones secreted by the adrenal gland are synthesized from what?

Answer 1

Cholesterol

Question 2

What is the function of aldosterone?(3)

Answer 2

•Regulates electrolyte and water balance.
•Increases reabsorption of 3Na in the kidney tubules.
•Cl follows passively, followed by bicarbonate and water.
•Increases the excretion of 2K by renal tubules.

Question 3

From anterior to posterior name the structures of the nephron

Answer 3

-Afferent arteriole
-Glomerulus
-bowman’s capsule)
-Efferent arteriole
- Proximal convoluted tubule
- Descending limb of the loop of henle
- Thin ascending limb of the loop of henle
- Thick ascending limb of the loop of henle
-Collecting ducts
-Papillary ducts

Question 4

What happens in the loop of henle?

Answer 4

Reabsorption of water(descending limb) and sodium and chloride ions(ascending limb).

Question 5

What happens in the distal convoluted tubules?(2)

Answer 5

•Secretion of ions, acids, toxins, drugs.
•Variable reabsorption of water, sodium and calcium ions.

Question 6

What happens in the collecting duct?

Answer 6

Variable reabsorption of water and reabsorption or secretion of hydrogen, potassium, bicarbonate ions and sodium.

Question 7

What happens in the papillary duct?

Answer 7

Delivery of urine to the minor calyx.

Question 8

Two types of cells found in the collecting duct

Answer 8

Principal cells
Intercalated cells

Question 9

Describe the role of the principal cells in potassium excretion

Answer 9

Aldosterone moves from circulation and combines with a cytoplasmic receptor inside the principal cells.
The aldosterone-receptor complex initiates transcription in the nucleus.
New protein channels and pumps are made.
Aldosterone-induced proteins modifies existing proteins.
Results in increased sodium reabsorption and excretion of potassium.

Question 10

Name 4 functions of cortisol

Answer 10

•Initiates gluconeogenesis in the liver.
•Causes protein catabolism in muscles.
•Causes lipolysis in fat cells.
•Suppresses immune system.

Question 11

What are the functions of androgens?

Answer 11

•Helps in the production of estradiol and testosterone.
• Libido

Question 12

What are the disorders of the adrenal cortex(5)

Answer 12

Addison’s disease( hypoaldosteronism)
Conn’s syndrome(hyperaldosteronism)
Cushing’s disease(increased cortisol)
Congenital adrenal hyperplasia(decreased cortisol)
Adrenogenital syndrome(excess androgens)

Question 13

What are the effects of addison’ disease?(5)

Answer 13

There is a primary hypo-activity of the adrenal glands.
•Low cortisol and aldosterone.
•High levels of potassium and low levels of Na and water.
•Hyperpigmentation due to excess production of melatonin because of high ACTH stimulation.
•Sx: loss of weight, hypoglycaemia, muscle weakness, vomiting, low BP, arrhythmias.
•Ultimate coma and death.

Question 14

What are the effects of hyperaldosteronism? (8)

Answer 14

• Primary-Conn’s syndrome.
  -This is caused by excess production of aldosterone.
  -Suppresses the renin activity.
  -Causes increased reabsorption of sodium and excretion of potassium.
  -This causes hypertension (water follows Sodium).
  -Also causes hypokalaemia.
• Secondary is caused by renin secreting tumors.
  -Or it can be ectopic, causes by ovarian tumors.

Question 15

What are the causes and effects of Cushing’s disease?

Answer 15

-Excess cortisol.
-Primarily caused by adrenal tumor, secondary can be excess ACTH or CRH production, ectopic, exogeneous.
-Clinical presentation involves, Low potassium and high sodium levels.
-Hyperglycaemia and glocosuria.
-Syndrome X.