「SHolroydAtWeilCornellMedQatar/Endocrinology/VasopressinADH/ControlToWaterIntake」の版間の差分
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//LEVEL:3 | //LEVEL:3 | ||
//RAND | //RAND | ||
With water intake, the plasma osmolarity {~=decreases~increases}. The effect would be the {=same as~opposite to} that of reabsorption of water by the kidney, which {=decreases~increases} plasma osmolarity. The effect of reabsorption would be {too weak~=too strong} prior to control by negative feedback. Negative feedback {~increases~=decreases} the synthesis, secretion, and blood concentration of vasopressin (anti-diuretic hormone, ADH). This in turn {increases~=decreases} the number of water channels in the kidney causing {increased~=decreased} water reabsorption. Urine osmolarity {increases~=decreases} while volume {~=increases~decreases}. This {decreases~=increases} plasma osmolarity, {~=returning to normal~separating from normal}. | With water intake, the plasma osmolarity {~=decreases~increases}. The effect would be the {=same as~opposite to} that of reabsorption of water by the kidney, which {=decreases~increases} plasma osmolarity. The effect of the reabsorption would be {too weak~=too strong} prior to control by negative feedback. Negative feedback {~increases~=decreases} the synthesis, secretion, and blood concentration of vasopressin (anti-diuretic hormone, ADH). This in turn {increases~=decreases} the number of water channels in the kidney causing {increased~=decreased} water reabsorption. Urine osmolarity {increases~=decreases} while volume {~=increases~decreases}. This {decreases~=increases} plasma osmolarity, {~=returning to normal~separating from normal}. | ||
</GIFT> | </GIFT> | ||
2019年9月1日 (日) 14:38時点における版
| With water intake the plasma osmolarity decreases, and negative feedback decreases the synthesis, secretion, and blood concentration of vasopressin (anti-diuretic hormone, ADH). |
video prior to water intake
Prior to water intake (at baseline), we will make the assumption that the subject is in homeostasis with normal plasma and urine osmolarities (isotonic) and urine volume.
video just after water intake
Step 1: With water intake, water enters the plasma and osmolarity decreases (the plasma becomes hypotonic).
Step 2: With reabsorption (through the water channels, which are increased by vasopressin, ADH, water enters the plasma and osmolarity decreases. This is the same effect as water intake. Thus, with the low plasma osmolarity produced by water intake (hypotonic plasma), the baseline strength of the plasma osmolarity-decreasing effect of reabsorption would be too strong. Control by negative feedback is needed.
video just after the decrease in vasopressin (ADH) caused by water intake
Step 3: With the baseline effect of the reabsorption (through the water channels, which are increased by vasopressin, ADH) being too strong, the negative feedback decreases the synthesis, secretion, and blood concentration of vasopressin (ADH).
Step 4: The water channel-increasing effect of vasopressin (ADH) becomes weaker, which decreases the number of water channels. This decreases the reabsorption of water by the kidney.
video showing the changes in plasma and urine after the decrease in vasopressin (ADH) caused by water intake
Step 5: The ratio of Na+ to water entering the plasma due to reabsorption increases. This increases plasma osmolarity. This will lead to an increase in the decreased plasma osmolarity from water intake (hypotonic plasma), returning it towards normal (baseline) osmolarity (isotonic plasma). Because a higher ratio of Na+ to water leaves the tubule due to reabsorption, the fluid remaining in the tubule has a lower osmolarity (hypotonic). Also, with the decrease in water reabsorption, there is more water remaining in the tubule. Overall, the urine becomes less concentrated (hypotonic) and higher in volume.
Challenge Quiz
With water intake, negative feedback increases decreases the synthesis, secretion, and blood concentration of vasopressin (anti-diuretic hormone, ADH).
With water intake, negative feedback increases decreases the number of water channels in the kidney.
With water intake, negative feedback increases decreases water reabsorption by the kidney.
With water intake, negative feedback increases decreases urine volume.
With water intake, negative feedback increases decreases urine osmolarity.
With water intake, negative feedback increases decreases plasma osmolarity.
With water intake, the plasma osmolarity decreases increases . The effect would be the same as opposite to that of reabsorption of water by the kidney, which decreases increases plasma osmolarity. The effect of the reabsorption would be too weak too strong prior to control by negative feedback. Negative feedback increases decreases the synthesis, secretion, and blood concentration of vasopressin (anti-diuretic hormone, ADH). This in turn increases decreases the number of water channels in the kidney causing increased decreased water reabsorption. Urine osmolarity increases decreases while volume increases decreases . This decreases increases plasma osmolarity, returning to normal separating from normal .