Hormonal Axis

Question 1

Describe the function of cortisol

Answer 1

Inhibits the immune system
Inhibits bone formation
Raises blood glucose
Increases metabolism
Increases alertness

Question 2

Describe the action of growth hormone

Answer 2

Stimulates muscle growth
Increases bone density and strength
Stimulates cell regeneration and reproduction
Stimulates growth of internal organs

Question 3

Describe the mechanism of PTH release

Answer 3

Released from the four parathyroid glands in response to:
low serum calcium
low magnesium
high serum phosphate

Question 4

Describe the function of parathyroid hormone

Answer 4

Raises serum calcium:
Increases number and activity of osteoclasts
Stimulates calcium reabsorption in kidney
Simulates conversion of vit D3 into calcitriol in the kidneys. The active form of vit D promotes calcium reabsorption in the small intestine.

Question 5

Describe the biochemical response to GHRH

Answer 5

GHRH is released from the hypothalamus
GH is released from the anterior pituitary gland
Insulin like growth hormone factor (IGF-1) is released from the liver

Question 6

Describe how cortisol is released

Answer 6

Corticotrophin release hormone (CRH) is released from hypothalamus
ACTH is released from anterior pituitary
Cortisol is released from adrenal glands

Question 7

Describe how renin is released

Answer 7

Juxtaglomerular cells secrete renin.

In response to low blood pressure.

Question 8

Describe the effects of renin release

Answer 8

Angiotensinogen released by the liver, is converted to angiotensin I.
ACE converts ATI int ATII in the lungs.
ATII causes vasoconstriction in blood vessels, and stimulates aldosterone release from the adrenal glands.
Aldosterone:
Increase Na reabsorption and K secretion in the distal tubule
Increase hydrogen secretion from the collecting ducts.
Intravascular volume is increases, as water follows Na by osmosis.