Antidiuretic hormone (ADH) targets the __________.

• A. pancreas
• B. liver
• C. kidneys
• D. thyroid gland

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the role of antidiuretic hormone (ADH). ADH is a hormone produced by the hypothalamus and stored in the posterior pituitary gland. Its primary function is to regulate water balance in the body by controlling the amount of water reabsorbed by the kidneys.
2. Step 2: Identify the target organ of ADH. ADH specifically acts on the kidneys, targeting structures called nephrons, which are the functional units of the kidneys. It increases the permeability of the collecting ducts to water, allowing more water to be reabsorbed into the bloodstream.
3. Step 3: Eliminate incorrect options. The pancreas is involved in insulin and glucagon secretion for blood sugar regulation, the liver is responsible for metabolic processes and detoxification, and the thyroid gland regulates metabolism through thyroid hormones. None of these organs are directly involved in water reabsorption.
4. Step 4: Confirm the correct answer. The kidneys are the organ responsible for filtering blood and maintaining fluid balance, making them the correct target for ADH.
5. Step 5: Relate this concept to physiology. The action of ADH on the kidneys helps prevent dehydration by conserving water, which is crucial for maintaining homeostasis in the body.