Answer
1) Anti-diuretic hormone (ADH)
- ADH is released from posterior pituitary gland.
- Its primary function is to increase water reabsorption in the
collecting duct of the nephron.
- ADH stimulates insertion of aquaporins on the wall of
collecting ducts.
- As water reasborption increases, the urine output is
decreased.
- As a result, small amount of more concentrated urine is
produced.
2) Aldosterone
- It is released by zona glomerulosa layer of adrenal
cortex.
- Aldosterone functions to increase sodium reabsorption at distal
convoluted tubules.
- Water also follows sodium and is reabsorbed in high
amount.
- As there is low water content in filtrate, urine output
is decreased.
3) Atrial natriuretic peptide (ANP)
- ANP is released from atria of the heart.
- It opposes the effect of aldosterone hormone.
- ANP increases excretion of sodium (prevents reabsorption) from
the distal convoluted tubule.
- As there is more sodium in the filtrate, water cannot leave the
renal tubule and reaborption do not occur.
- As a result, urine output increases.