Lacking protein in your diet can result in low levels of the protein albumin in your blood. Explain how this could affect the water content and volume of your blood.

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Albumin is the primary protein found in the blood. Produced by the liver, albumin constitutes around 54% of the plasma proteins found in the blood. Because of its abundance, albumin is responsible for maintaining the oncotic (because it is a colloid) blood pressure, meaning that it controls the movement of water in and out of the blood vessels by maintaining a certain concentration gradient. A lower concentration of albumin protein molecules in the plasma would mean that there would emerge a lower overall concentration of molecules in the blood plasma in comparison with the interstitial space. Osmotic pressure, which directs the flow of water from an area of high to low concentration, would thus push water out of the blood vessels and into the surrounding body tissue.

Low protein in the diet would also affect the rate of filtration that happens at the glomerulus of the kidneys. Again, because of the higher osmotic pressure that would exist in the blood vessels as a result of depleted albumin concentration, the blood that passes out from the afferent arteriole and on to the renal glomerulus would have a higher osmotic pressure. Thus, more total blood volume would be absorbed by the renal nephrons during the process of filtration. The heightened rate of filtration would lead to an overall increase in urine output, and a total decrease in the volume of the blood. In both cases, blood volume and water content would decrease, because with a lower albumin concentration, osmotic pressure would force water out of the blood vessels and into either the interstitial space or the renal nephrons.

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