HSS 2342 Lecture Notes - Lecture 5: Water Intoxication, Hyponatremia, Body Composition
Document Summary
Water and body fluids: water constitutes majority of body weight, 60% Water balance and recommended intake: cellular uids. Intravascular uid - inside blood vessels: water intake. When inadequate, the blood becomes concentrated, the mouth becomes dry, and the hypothalamus initiates drinking behaviour. When excessive, the stomach expands and stretch receptors send signals to stop drinking. Similar signals are sent from receptors in the heart as blood volume increases. Thirst response lags behind the body"s need for water. When too much water is lost from the body and not replaced, dehydration develops. Water, beverages, foods, condensation reactions, oxidation of energy yielding nutrients: water losses must excrete enough water to carry away the waste products generated by a day"s metabolic activities via urine. Needs vary, depending on diet, activity, environmental temperature, and humidity. Ai (average intake) for total water (water in other foods and beverages as well) = 2-3 l: health e ects. Hard water - high concentrations of calcium and magnesium.