Regulation of Water Output (Nursing)

00:01 So obligatory water loss explains why we cannot live without actually ingesting or bringing in more water.

00:11 We are going to lose water through insensible water loss from the lungs, the skin, and the feces, as well as sensible water loss from our urine, where we need to excrete waste from the body.

00:28 This accounts for about a 500 milliliters of water loss minimum in a day.

00:35 The volume of urine excreted, and the solute concentration are also going to depend on fluid intake, diet, and as well as water loss via other avenues.

00:49 Other factors that may trigger antidiuretic hormone release, which is going to decrease water loss in our urine include large changes in our blood volume or blood pressure.

01:02 If we have a decreased blood pressure, this causes an increase antidiuretic hormone release.

01:10 This is going to be due to things like the blood vessel baroreceptors and the renin angiotensin aldosterone mechanism.

01:19 The increase in antidiuretic hormone release is going to lead to more water reabsorption to the extracellular fluid, which will then increase our blood volume, which consequently will increase the blood pressure.

01:36 And decrease in blood volume or blood pressure can be caused by many things.

01:42 This includes intense sweating during exercise, vomiting or diarrhea when one is sick, severe blood loss, traumatic burns, and also prolonged fever.

01:57 So if we look at this or to summarize this, a decreased plasma volume is going to lead to a decreased blood pressure.

02:07 Also, an increased extracellular fluid osmolality, or an increase in the sodium concentration in our plasma is also going to set off the same type of mechanism that's going to lead to the release of antidiuretic hormone.

02:26 Starting with the decrease blood pressure, we find that the baroreceptors, and the atria of the heart and the large vessels are going to stimulate the posterior pituitary to release antidiuretic hormone.

02:41 If we look at the osmolality of our extracellular fluids, we find that this also can stimulate the posterior pituitary to release antidiuretic hormone.

02:54 The release of antidiuretic hormone is then going to trigger the collecting ducts of the kidneys, which are going to lead to more water reabsorption in the kidneys.

03:06 If we are reabsorbing more water, that means we are secreting or excreting less water.

03:12 So this is going to lead to a very low amount of urine.

03:16 But it's also going to lead to an increase in our plasma volume, which is directly related to an increase in our blood pressure.

03:25 And it's also going to lead to a decrease in our extracellular fluid osmolality which is going to lead to our bodies returning back to the homeostasis.

03:37 Once this occurs, negative feedback will feed back to the hypothalamus, which will then stop this process and stop the release of more antidiuretic hormone.