Skip to main content
Ch. 26 The Urinary System
Martini - Fundamentals of Anatomy and Physiology 12th Edition
Martini, Nath, Bartholomew12th EditionFundamentals of Anatomy and PhysiologyISBN: 9780137854011Not the one you use?Change textbook
All textbooksMartini, Nath, Bartholomew 12th EditionCh. 26 The Urinary SystemProblem 19
Chapter 25, Problem 19

When ADH levels rise, 
(a) The amount of water reabsorbed increases.
(b) The DCT becomes impermeable to water.
(c) The amount of water reabsorbed decreases.
(d) Sodium ions are exchanged for potassium ions.

Verified step by step guidance
1
Understand the role of Antidiuretic Hormone (ADH) in the kidney's function, specifically how it affects water reabsorption in the nephron.
Recall that ADH primarily acts on the distal convoluted tubule (DCT) and collecting ducts to regulate water permeability.
Recognize that when ADH levels rise, it increases the permeability of the DCT and collecting ducts to water by promoting the insertion of aquaporin channels into the membranes.
This increased permeability allows more water to be reabsorbed from the filtrate back into the bloodstream, concentrating the urine and conserving body water.
Based on this understanding, identify which option correctly describes the effect of increased ADH levels on water reabsorption.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Antidiuretic Hormone (ADH) Function

ADH, also known as vasopressin, regulates water balance by increasing water reabsorption in the kidneys. It acts primarily on the collecting ducts, making them more permeable to water, which helps concentrate urine and reduce water loss.
Recommended video:
Guided course
13:06
Review of Major Hormones

Water Reabsorption in the Nephron

Water reabsorption occurs mainly in the proximal tubule, loop of Henle, distal convoluted tubule (DCT), and collecting ducts. ADH specifically increases permeability in the collecting ducts, allowing more water to be reabsorbed back into the bloodstream.
Recommended video:
3:25
2) Reabsorption in the Nephron Loop

Distal Convoluted Tubule (DCT) Permeability

The DCT is involved in selective reabsorption and secretion but is generally impermeable to water unless influenced by hormones. ADH primarily affects the collecting ducts rather than the DCT, so the DCT does not become impermeable to water when ADH levels rise.
Recommended video:
4:24
3) Reabsorption in the Distal Tubule and Collecting Duct
Related Practice
Textbook Question

What interacting controls stabilize the glomerular filtration rate (GFR)?

1
views
Textbook Question

When the renal threshold for a substance exceeds its tubular maximum:

(a) More of the substance will be filtered

(b) More of the substance will be reabsorbed

(c) More of the substance will be secreted

(d) The amount of the substance that exceeds the tubular maximum will be found in the urine

(e) Both a and d occur

2
views
Textbook Question

The control of blood pH by the kidneys during acidosis involves 

(a) The secretion of hydrogen ions and reabsorption of bicarbonate ions from the tubular fluid

(b) A decrease in the amount of water reabsorbed

(c) Hydrogen ion reabsorption and bicarbonate ion loss

(d) Potassium ion secretion

1
views
Textbook Question

How are proteins excluded from filtrate? Why is this important?

2
views
Textbook Question

Sympathetic activation of nerve fibers in the nephron causes 

(a) the regulation of glomerular blood flow and pressure, 

(b) the stimulation of renin release from the juxtaglomerular complex, 

(c) the direct stimulation of water and Na+ reabsorption, 

(d) all of these.

1
views
Textbook Question

Sodium reabsorption in the DCT and in the cortical portion of the collecting system is accelerated by the secretion of 

(a) ADH

(b) Renin

(c) Aldosterone

(d) Erythropoietin

1
views