Renal System

Urea (a waste product) is lipid soluble, so it can passively move out of the filtrate into the tubule cells. It is secreted back into the filtrate to effect its excretion.

Carbon dioxide and water react to form carbonic acid which dissociates into hydronium ions and bicarbonate ions. The bicarbonate ions are transported to the blood, while the hydronium is excreted in acidic urine.

A diuretic causes a greater volume of urine to be produced. ADH promotes the reabsorption of water, so a lack of it will mean less water is reabsorbed from the filtrate, and a greater volume of urine will be produced. The other three choices will cause a decrease in urine volume.

The granular cells of the afferent arteriole respond to low blood pressure by releasing renin. As a result, angiotensin II would form which causes systemic vasoconstriction, which increases blood pressure, which dilates the afferent arteriole and increases glomerular filtration rate.

About 2/3 of water in the filtrate is absorbed from the PCT.

Angiotensin II promotes general vasoconstriction (which raises blood pressure) and stimulates the adrenal cortex to release aldosterone.

the renal cortex is before the papilla; the efferent arteriole is not part of flow of the filtrate; Bowman’s capsule comes before the loop of Henle.