Why is water balance by ADH an example of negative feedback?
Negative feedback is when a change in the internal environment triggers a hormonal response, in this case, to counteract that change. ADH, which is antidiuretic hormone, controls water balance by controlling the osmolarity of the blood. For example, when you suffer diarrhea or you’re sweating a lot, you lose a significant amount of water, affecting the ratio of salts to water in your body. ADH is stimulated then, and is discharged from the brain into the bloodstream where it reaches the kidneys. ADH causes the kidneys to become more permeable to water (this is positive feedback, in which a change is amplified), and thus the kidneys are more receptive to absorbing water, and maintaining the optimum water balance. After recognising that the water balance has been normalised, release of ADH is reduced. That is negative feedback. On the other hand if you consume a lot of water, your balance is also changed. in this case, little ADH would be released and you would release your water through
