Question

1) What will happen if Angiotensin Converting Enzyme production is increased?

Choose whether they increase or decrease:

a) Blood Volume

b) MAP

c) GFR

d) Vasopressin release

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2) Will this cause a positive or negative sodium balance?

Answer 1

Answer 1) angiotensin Converting Enzyme( ACE) is an enzyme that converts angiotensin 1 into angiotensin 2.If production of this enzyme is increased, it will lead to an increase in angiotensin 2. Angiotensin has is a potent vasoconstrictor and also has central effects.It also increases aldosterone release from adrenal cortex. Thus the answers are following:

a) Blood volume- angiotensin 2 will cause more release of aldosterone and aldosterone will cause sodium and water reabsorption from renal tubules. Thus blood volume will increase.

b) MAP- mean arterial pressure will increase because arteries will undergo vasoconstriction under the effect of angiotensin 2.Also increased blood volume will increase blood pressure.

c)GFR- angiotensin 2 constricts the efferent arteriole.This will increase the hydrostatic pressure in the glomerulus. Thus glomerular filtration rate will increase.

d) vasopressin release- angiotensin 2 also has central effects.It increases vasopressin release from the posterior pituitary.

Answer 2) Sodium balance is measured by the difference in the amount of sodium intake and sodium excreted. Thus, increased angiotensin will increase aldosterone release. This will increase sodium reabsorption. Thus there is a positive sodium balance. Also increased arterial pressure is associated with positive sodium balance and decreased arterial pressure is associated with negative sodium balance.