NTDT200 Chapter Notes - Chapter 12-13: Broccoli, Spinach, Constipation
6 Sep 2016
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Water constitutes majority of body weight (60% of adult) Body composition influences how much body weight is water. 75% of lean tissue, 25% of fat tissue. Smaller amounts in females, elderly, & obese people due to less lean tissue. Water balance = balance between water intake and output. Influenced by thirst (= conscious desire to drink) and satiety. Thirst response lags behind body"s need for water. Dehydration = condition in which water output exceeds input. More body weight lost from dehydration symptoms more severe. Water intoxication = condition in which body water contents are too high. Rare; 10-20 l within few hours hyponatremia (=diluted sodium concentration) Kidney central to regulation of blood volume and blood pressure. Functions to reabsorb needed substances and excrete wastes. Adjusts volume and concentration of urine according to changes in body. Obligatory water excretion (minimum water excretion) = 2 c/day as urine. Needs vary depending on diet, activity, climate, and humidity.
