Question

_____ stimulates release of aldosterone and antidiuretic hormone, which decrease water excretion

A) Renin

B)angiotensin II

Answer 1

Option B-Angiotensin 2.

When you Have low Plasma Volume (High Osmolarity)or Low BP .It stimulates the release of Renin from the juxtaglomerular cells of Kidneys.

Renin acts on Angiotensiogen Released from the Liver & Converts Angiotensiogen(Inactive)----Angiotensin 1(Active).

Angiotensin Converting Enzyme(ACE) Acts on Angiotensin 1 and converts it into-----------Angiotensin 2.

Angiotensin 2 have the Following Actions.

1.Stimulates CNS to increase ADH( vasopressin) production from the Posterior Pituitary

2.Acts on venous and arterial smooth muscle which cause vasoconstriction.

3.Increases aldosterone secretion .

**ADH Acts on Collecting Duct------to the V2 receptors on the cell surface of tubular cells--- intracellular cascade that results in formation of water channel, aquaporin-2.

Through These water channels,There is Reabsorbtion of Water From The Filtrate(Urine) into the Interstitium then to Blood.

**Aldosterone acts on renal collecting ducts-----stimulate reabsorption of Na+, secretion of K+& H+ .