insensible water loss
26.2 | Water Balance By the end of this section, you will be able to: Explain how water levels in the body influence the thirst cycle Identify the main route by which water leaves the body Describe the role of ADH and its effect on body water levels Define dehydration and identify common causes of dehydration On a typical day, the average adult will take in about 2500 mL almost 3 quarts of aqueous fluids. Although most of the intake comes through the digestive tract, about 230 mL 8 ounces per day is generated metabolically, in the last steps of aerobic respiration. Additionally, each day about the same volume 2500 mL of water leaves the body by different routes; most of this lost water is removed as urine. The kidneys also can adjust blood volume though mechanisms that draw water out of the filtrate and urine. The kidneys can regulate water levels in the body; they conserve water if you are dehydrated, and they can make urine more dilute to expel excess water if necessary. Water is lost through the skin through evaporation from the skin surface without overt sweating and from air expelled from the lungs. This type of water loss is called insensible water loss because a person is usually unaware of it.