Question

A patient has been diagnosed with high blood pressure. With your knowledge of renin and its action on the body, explain how lowering the levels of renin release may help to lower blood pressure in the patient?

To obtain full marks, you would need to explain 5 different details about how renin might act to control blood pressure in the patient.

Answer 1

If a patient has high blood pressure then there will be high blood volume and blood flow to kidney increases then following event takes place:-

-- Due to high pressure of blood in nephron there will be low reabsorption of sodium at PCT but at DCT sodium reabsorption will be high which leads to less release of Renin.

-- As blood pressure increases it is sensed by carotid sinus and there will be less stimulation of sympathetic outflow which acts on adrenergic receptor to decrease level of Renin.

In this way due to high blood pressure renin level decrease.

Renin converts Angiotensinogen to angiotensin I so due to low level of Renin there will be less angiotensin I .Now an enzyme convert less angiotensin I to less angiotensin II. Due to low level of angiotensin II ,there will

1. Less contraction of smooth muscle leads to low cardiac output .

2. Less release of aldosterone as aldosterone is released by action of angiotensin II on kidney.aldosterone low level causes less absorption of sodium and water which decreases blood volume.

3. Less stimulation of hypothalamus to release ADH which leads to low absorption of sodium and water which leads to low blood volume.

4. Less stimulation of sympathetic system which leads to low blood volume.

5. Less stimulation of thirst centre .

Conclusion is that due to low level of Renin above 5 condition occurs which leads to low blood pressure and blood volume.

In this way Renin regulates blood pressure in body together with angiotensin.