Lesson 4: Control of Urine Production

Question 1

Urine Output

Answer 1

The permeability of the distal tubule and the collecting duct is controlled
by a hormone called anti – diuretic hormone (ADH).

ADH is secreted by the pituitary gland.

ADH increases the permeability of the distal tubule and collecting duct
causing water to be removed from the filtrate when the body needs to
conserve water.

Question 2

Urine

Answer 2

When the body needs to eliminate excess water, ADH is inhibited and more
water remains in the filtrate.

Drugs such as caffeine and alcohol block the release of ADH and increase the
volume of urine output.

Increased urine output can be a symptom of conditions such as diabetes.

The increased level of blood sugar can overload the active transport
systems of the proximal tubule.

This causes glucose to remain in the filtrate as it moves through the loop
of Henle, distal tubule and collecting duct.

The glucose retains water in the filtrate, offsetting the system that is
designed to remove it. The result is a large volume of sugary urine.