Related Experiment Video

Updated: Aug 18, 2026

A Decentralized (Ex Vivo) Murine Bladder Model with the Detrusor Muscle Removed for Direct Access to the Suburothelium during Bladder Filling
06:36

A Decentralized (Ex Vivo) Murine Bladder Model with the Detrusor Muscle Removed for Direct Access to the Suburothelium during Bladder Filling

Published on: November 28, 2019

Experimental validation of the countercurrent model of urinary concentration

James A Schafer1

  • 1Dept. of Physiology and Biophysics, University of Alabama at Birmingham, 1918 University Blvd., Rm. 834 MCLM, Birmingham, AL 35294-0005, USA. jschafer@uab.edu

American Journal of Physiology. Renal Physiology
|October 12, 2004
PubMed

More Related Videos

Detrusor Underactivity Model in Rats by Conus Medullaris Transection03:26

Detrusor Underactivity Model in Rats by Conus Medullaris Transection

Published on: August 28, 2020

An In Vitro Bladder Model of Catheter-Associated Urinary Tract Infection07:57

An In Vitro Bladder Model of Catheter-Associated Urinary Tract Infection

Published on: June 24, 2025

Related Concept Videos

Formation of Dilute Urine01:20

Formation of Dilute Urine

The formation of dilute urine is a critical renal adaptation that maintains fluid balance, particularly during periods of high fluid intake. This process primarily involves the juxtamedullary nephrons. By adjusting the permeability of water and ions in response to physiological conditions, the kidneys can either conserve or excrete water, resulting in concentrated or dilute urine.
Filtrate Osmolarity in the PCT
Initially, as the filtrate passes through the proximal convoluted tubule (PCT), its...
Formation of Concentrated Urine01:23

Formation of Concentrated Urine

There is a gradient of solutes in the interstitial fluid from the renal cortex through the medulla, known as the medullary osmotic gradient. The juxtamedullary nephrons establish and maintain this gradient using countercurrent mechanisms with loops extending deep into the medulla. These nephrons also use countercurrent mechanisms to regulate urine volume and concentration. The interaction between the descending and ascending limbs of the nephron loop creates an osmotic gradient through...
One-Compartment Open Model: Urinary Excretion Data and Determination of k01:11

One-Compartment Open Model: Urinary Excretion Data and Determination of k

The one-compartment open model leverages urinary excretion data to estimate renal clearance, which gauges the kidney's capacity to expel a drug. This method offers several benefits, including directly measuring drug elimination and assessing the kidney's contribution to overall drug clearance. However, this approach has limitations. It assumes sole renal excretion of the drug, which is not true for all drugs. Accurate urinary excretion and plasma drug concentration measurement can also be...
Physiology of the Genitourinary System I: Renal Blood Flow and Glomerular Filtration01:29

Physiology of the Genitourinary System I: Renal Blood Flow and Glomerular Filtration

The kidneys are vital organs responsible for regulating blood filtration, waste excretion, and fluid balance, all of which are crucial for maintaining homeostasis. Renal physiology examines renal blood flow, glomerular filtration, and urine formation, ensuring the body’s internal environment remains stable.Renal Blood FlowThe kidneys receive about 20-25% of the cardiac output, typically around 1200 mL of blood per minute in an average adult. Blood flows into the kidneys through the renal...
Physiology of the Genitourinary System II: Tubular Reabsorption and Secretion01:22

Physiology of the Genitourinary System II: Tubular Reabsorption and Secretion

The kidneys maintain homeostasis through filtration, reabsorption, and secretion. Tubular reabsorption and secretion are crucial in forming urine and regulating electrolytes, water balance, and waste elimination.Tubular Reabsorption and Secretion ProcessesTubular reabsorption is the process that reclaims essential substances such as electrolytes, glucose, amino acids, and water from the glomerular filtrate back into the bloodstream. This is achieved through passive and active transport...
Physiology of the Genitourinary System III: Urine Concentration and Dilution01:20

Physiology of the Genitourinary System III: Urine Concentration and Dilution

The kidneys concentrate or dilute urine to maintain water and electrolyte balance. Nephrons, particularly the loop of Henle, play a crucial role in this process through the countercurrent multiplication system. This system establishes a high osmolarity in the renal medulla, which is essential for water reabsorption. In the loop of Henle’s descending limb, water is reabsorbed into the surrounding medulla due to its permeability to water. In contrast, the ascending limb actively transports...