A drawing of the renal system before and after fasting.
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Burkeen’s project illustrates the effects of fasting on urine concentration as a result of hormonal regulation and renal action to counter the effects of fasting. This is based off of the course objective to describe kidney function.
As explained in this picture, the kidneys are moderated by ADH, or anti-diuretic hormone. This hormone is released when body water levels get too low: in order to retain more water, ADH is sent out to the kidneys, where the epithelial linings of the loop of Henle respond to ADH by developing more aquaporins, which are gate proteins that facilitate the re-uptake of water. After a period of time with no ADH signals, these epithelial linings will stop producing additional aquaporins, allowing the urine to be more dilute.
In fasting, there is minimal water or food being taken in. Because of this, our body is receiving far less water than normal, and will quickly dehydrate if we excrete the normal amount of water through urine. So, once the brain can pick up on those low water levels, it releases ADH to facilitate water retention.
Additionally, in periods of fasting, we may not be maintaining adequate levels of electrolytes, because we aren’t taking in the food that would be replacing the extra that we excrete in urine. So, the body also facilitates the further re-uptake of electrolytes to prevent the body from running out of these vital salts.
Overall, in fasting for significant periods of time, the body is going to greatly increase water retention through ADH regulation, and electrolytes will also be more fully retained. This leads to far less urine being produced, and that which is released is very concentrated due to the efficient re-absorption of water and electrolytes in the kidneys.
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Burkeen’s project illustrates the effects of fasting on urine concentration as a result of hormonal regulation and renal action to counter the effects of fasting. This is based off of the course objective to describe kidney function.
As explained in this picture, the kidneys are moderated by ADH, or anti-diuretic hormone. This hormone is released when body water levels get too low: in order to retain more water, ADH is sent out to the kidneys, where the epithelial linings of the loop of Henle respond to ADH by developing more aquaporins, which are gate proteins that facilitate the re-uptake of water. After a period of time with no ADH signals, these epithelial linings will stop producing additional aquaporins, allowing the urine to be more dilute.
In fasting, there is minimal water or food being taken in. Because of this, our body is receiving far less water than normal, and will quickly dehydrate if we excrete the normal amount of water through urine. So, once the brain can pick up on those low water levels, it releases ADH to facilitate water retention.
Additionally, in periods of fasting, we may not be maintaining adequate levels of electrolytes, because we aren’t taking in the food that would be replacing the extra that we excrete in urine. So, the body also facilitates the further re-uptake of electrolytes to prevent the body from running out of these vital salts.
Overall, in fasting for significant periods of time, the body is going to greatly increase water retention through ADH regulation, and electrolytes will also be more fully retained. This leads to far less urine being produced, and that which is released is very concentrated due to the efficient re-absorption of water and electrolytes in the kidneys.