When plasma volumes are maintained at or near normal levels, turgidity of the blood does not occur and the heart can continue to pump blood to the body surface and extremities, thus assisting heat dissipation and avoiding potential ‘explosive heat death’. Other factors, which play a role in maintaining plasma volume are connected with the attraction of water. Glucose levels rise on dehydration, resulting in hyperglycaemia; the hygroscopic glucose then attracts water to the blood. Like glucose, urea is also hygroscopic and its reabsorption into the blood acts as an additional water transfer agent. Prolactin and oxytocin, normally associated with.
