Question

Which of the following is not true?

• A. Function of the collecting duct is the formation and collection of urine.
• B. If the body is dehydrated, the hormone ADH acts on the collecting duct making it permeable to water.
• C. If the body is well hydrated, very little water is reabsorbed in the collecting duct.
• D. The alpha intercalated cells play a role in base secretion, that is bicarbonate. The beta cells however secrete acidic fluid, that is, H+ secretion.

Answer 1

The correct option is D The alpha intercalated cells play a role in base secretion, that is bicarbonate. The beta cells however secrete acidic fluid, that is, H+ secretion.

The obvious function of the collecting duct is the formation and collection of urine. The amount of water that constitutes the urine is decided here and is under the regulation of a hormone called ADH or the antidiuretic hormone or vasopressin, which as the name suggests, is a hormone that decreases the quantity of urine. It does this according to the hydration levels of the body; if the body is well hydrated, very little water is reabsorbed in the collecting duct. But under dehydrated conditions the hormone ADH acts on the collecting duct making it permeable to water. The water passively moves out of the collecting duct. The alpha intercalated cells play a role in acid secretion, or hydrogen ions secretion. The beta cells however secrete bases, that is, bicarbonate. These cells play a role in the pH balance of blood. Some of these intercalated cells are present in the late DCT too, and are the cells responsible for the hydrogen ions secretion.