SHolroydAtWeilCornellMedQatar/Endocrinology/VasopressinADH/ControlToSweating
| With sweating the plasma osmolarity increases, and negative feedback increases the synthesis, secretion, and blood concentration of vasopressin (anti-diuretic hormone, ADH). |
video before sweating
Before sweating (at baseline), we will make the assumption that the subject is in homeostasis with adequate strength of the plasma osmolarity-decreasing effect of reabsorption (through the water channels, which are increased by vasopressin, ADH) as well as normal plasma and urine osmolarities (isotonic) and urine volume.
video just after sweating
Step 1: With sweating, water leaves the plasma and osmolarity increases (becomes hypertonic).
Step 2: This is in the opposite direction to the plasma osmolarity-decreasing effect of the reabsorption (through the water channels, which are increased by vasopressin, ADH). Thus, although the strength of the plasma osmolarity-decreasing effect of reabsorption (through the water channels, which are increased by vasopressin, ADH) was adequate before sweating (at baseline), this strength is now too weak (blue) to reverse the high plasma osmolarity (hypertonic plasma) produced by sweating. Control by negative feedback is needed.
video just after the increase in vasopressin (ADH) caused by sweating
Step 3: With the strength of the plasma osmolarity-decreasing effect of the reabsorption (through the water channels, which are increased by vasopressin, ADH) before sweating (at baseline) being too weak (blue), the negative feedback increases (red) (the synthesis, secretion, and blood concentration of) vasopressin (ADH).
Step 4: The water channel-increasing effect of vasopressin (ADH) becomes stronger, which increases the number of water channels. This increases the reabsorption of water by the kidney.
video showing the changes in plasma and urine after the increase in the reabsorption
Step 5: With the increase in water reabsorption, diluted (hypotonic) solution enters the plasma. This decreases plasma osmolarity. This will lead to a reverse in the increased plasma osmolarity from sweating (hypertonic plasma), decreasing it towards normal (baseline) osmolarity (isotonic plasma). Because diluted (hypotonic) solution leaves the tubule due to reabsorption, the fluid remaining in the tubule has a higher osmolarity (hypertonic). Also, with the increase in water reabsorption, there is less water remaining in the tubule. Overall, the urine becomes more concentrated (hypertonic) and lower in volume.
Challenge Quiz
With sweating, negative feedback increases decreases the synthesis, secretion, and blood concentration of vasopressin (anti-diuretic hormone, ADH).
With sweating, negative feedback increases decreases the number of water channels in the kidney.
With sweating, negative feedback increases decreases water reabsorption by the kidney.
With sweating, negative feedback increases decreases urine volume.
With sweating, negative feedback increases decreases urine osmolarity.
With sweating, negative feedback increases decreases plasma osmolarity.
With sweating, water enters leaves the plasma and osmolarity increases decreases .This is in the same direction as opposite direction to the plasma osmolarity-decreasing effect of the reabsorption (through the water channels, which are increased by vasopressin, ADH). Thus, although the strength of the plasma osmolarity-decreasing effect of reabsorption (through the water channels, which are increased by vasopressin, ADH) was too weak adequate too strong before sweating (at baseline), this strength is now too strong adequate too weak to reverse the high plasma osmolarity produced by sweating. The negative feedback increases decreases (the synthesis, secretion, and blood concentration of) vasopressin (ADH). The water channel-increasing effect of vasopressin (ADH) becomes stronger weaker , which increases decreases the number of water channels. With the increase decrease in water reabsorption by the kidney, concentrated diluted solution enters the plasma. This increases decreases plasma osmolarity. This will lead to the increased decreased plasma osmolarity from sweating, increasing decreasing it towards separate from normal (baseline) osmolarity. Because concentrated diluted solution leaves the tubule due to reabsorption, the fluid remaining in the tubule has a higher lower osmolarity. Also, with the increase decrease in water reabsorption, there is more less water remaining in the tubule. Overall, the urine becomes more concentrated diluted and higher lower in volume.