If a person's nephron collecting duct is unable to reabsorb water, what will be the urine output?

The nephron is the functional unit of the kidney, and its collecting duct plays a critical role in the regulation of water reabsorption. When the collecting duct is unable to reabsorb water, it disrupts the kidney's ability to concentrate urine.

In a healthy nephron, the collecting duct normally reabsorbs water based on the body's hydration status, influenced by hormones such as antidiuretic hormone (ADH). If water reabsorption is impaired, less water is reabsorbed back into the bloodstream, resulting in more water being excreted in the urine. Consequently, the urine will contain a higher volume of water and will be less concentrated in terms of solutes.

Therefore, when the collecting duct fails to reabsorb water, the resulting urine will be dilute, reflecting a high water content and lower solute concentration. This phenomenon can lead to increased urine output, as less water is returning to the body. In summary, the inability of the nephron collecting duct to reabsorb water directly leads to the production of dilute urine.