What effect does antidiuretic hormone (ADH) have on the nephron? a. It increases water permeability of the descending limb of the loop of Henle. b. It decreases water permeability of the descending limb of the loop of Henle. c. It increases water permeability of the collecting duct. d. It decreases water permeability of the collecting duct.

Verified step by step guidance

1. Understand the role of antidiuretic hormone (ADH): ADH is a hormone that helps regulate water balance in the body by controlling the amount of water reabsorbed by the kidneys.
2. Identify the location of ADH action: ADH primarily acts on the collecting ducts of the nephrons in the kidneys.
3. Recognize the effect of ADH on water permeability: When ADH is present, it makes the cell membranes of the collecting ducts more permeable to water.
4. Analyze the options given in the question: Option c states that ADH increases water permeability of the collecting duct, which aligns with the action of ADH as described.
5. Conclude the correct answer: Based on the understanding of ADH's role and action, the correct answer is c. It increases water permeability of the collecting duct.

Key Concepts

Antidiuretic Hormone (ADH)

Antidiuretic hormone, also known as vasopressin, is a peptide hormone produced by the hypothalamus and released by the posterior pituitary gland. Its primary function is to regulate water balance in the body by promoting water reabsorption in the kidneys, particularly in the collecting ducts of the nephron. This hormone plays a crucial role in maintaining blood pressure and osmolarity.

Nephron Structure and Function

The nephron is the functional unit of the kidney, responsible for filtering blood and forming urine. It consists of several parts, including the glomerulus, proximal tubule, loop of Henle, distal tubule, and collecting duct. Each segment has specific roles in reabsorption and secretion, with the collecting duct being particularly influenced by ADH to control water reabsorption.

Water Permeability in the Nephron

Water permeability in the nephron refers to the ability of the nephron segments to allow water to pass through their membranes. In the presence of ADH, the collecting duct becomes more permeable to water due to the insertion of aquaporin channels, facilitating increased water reabsorption. This process is essential for concentrating urine and conserving water in the body.