SHolroydAtWeilCornellMedQatar/Endocrinology/VasopressinADH/ControlToWaterIntake

POINT!

Intake of water will decrease plasma osmolarity. This will in turn lead to a decrease in the synthesis, secretion and blood concentration of ADH.

動画と音声での説明

飲水前の動画
Prior to drinking we assume our subject is in homeostasis with normal plasma and urine osmolarities and volumes.

飲水直後、調節前の動画
Steps 1 and 2: Water was taken. Water will enter the plasma and its osmolarity will decrease. Both intake of water and the ADH/water channels/reabsorption of water by the kidney will decrease plasma osmolarity, having the same effect. Thus, in this case with low plasma osmolarity, the effect of ADH/water channels/reabsorption would be too much.

飲水に対してADHが低下した直後の動画
Steps 3 and 4: With too much effect of ADH/water channels/reabsorption, the negative feedback decreases (the synthesis, secretion, and blood concentration of) ADH. The ADH-facilitating effect on the water channels will decrease, decreasing the number of water channels. This decreases the reabsorption of water by the kidney.

飲水に対してADHが低下した後の血漿、尿の2次的変化の動画
Step 5: The ratio of Na+ to water reabsorption by the kidney increases. This means plasma osmolarity increases. The decreased plasma osmolarity from intake of water will increase returning to normal. Because a higher ratio of Na+ is reabsorbed the fluid left in the tubule now has a lower osmolarity. The decrease in the number of water channels decreases water reabsorption so there is more water. So overall the urine becomes dilute and high volume.

Challenge Quiz

<GIFT> //LEVEL:2 //RAND The negative feedback reaction to an increased intake of water is a(n) {increase~=decrease} of ADH secretion. //LEVEL:3 //RAND

The negative feedback reaction to an increased intake of water is a(n) {increase~=decrease} of aquaporin channels in the kidney. 

//LEVEL:2 //RAND The negative feedback reaction to an increased intake of water is a(n) {increase~=decrease} in water reabsorption by the nephron.

//LEVEL:3 //RAND

The negative feedback reaction to an increased intake of water is a(n) {~=increase~decrease} in urine volume. 

//LEVEL:3 //RAND The negative feedback reaction to an increased intake of water is a(n) {increase~=decrease} of urine osmolarity.

//LEVEL:3 //RAND The negative feedback reaction to an increased intake of water is a(n) {~=increase~decrease} of plasma osmolarity.

//LEVEL:3 //RAND When you drink water the plasma osmolarity {~=decreases~increases}. This has the effect of {increasing~=decreasing} the release ADH. This in turn {increases~=decreases} the production of aquaporins by the nephron causing {increased~=decreased} water reabsorption. Urine osmolarity will {increase~=decrease} while volume will {~=increase~decrease}. This will {decreasing~=increasing} plasma osmolarity {~=returning to normal~separationg fromnormal}.