SHolroydAtWeilCornellMedQatar/Urology/Kidney/Tubules/WaterChannels/EffectOfDecrease

POINT!

With a decrease in the number of water channels, water reabsorption from the tubule decreases.

narrated video explanation

Prior to the number of water channels decreasing (at baseline), we will make the assumption that the subject is in homeostasis with normal plasma and urine osmolarities (isotonic) and urine volume.

Step 1: Suppose that the number of water channels decreases. Step 2: With the decrease in the number of water channels, water reabsorption from the tubule decreases.

Step 3:With the decrease in water reabsorption, concentrated (hypertonic) solution enters the plasma. This increases plasma osmolarity (concentrated, hypertonic). Because concentrated (hypertonic) solution leaves the tubule due to reabsorption, the fluid remaining in the tubule has decreased osmolarity (diluted, hypotonic). Also, with the decrease in water reabsorption, there is more water remaining in the tubule. Overall, the urine becomes diluted and increases in volume.

Challenge Quiz

1.

With a decrease in the number of water channels, water reabsorption from the tubule increases decreases  正解!.

2.

With a decrease in the number of water channels, urine volume increases decreases  正解!.

3.

With a decrease in the number of water channels, urine osmolarity increases decreases  正解!.

4.

With a decrease in the number of water channels, plasma osmolarity increases decreases  正解!.