Regulation of fluid that bathes our cells homeostasis. Ingestive behavior: intake of food, water and minerals such as sodium. When a sufficient amount of drinking occurs, the satiety mechs stop further drinking in anticipation of the replenishment that will occur later. Thirst osmometric and volumetric moisture lost through evaporation is pure distilled water. Osmometric thirst is when solute concentration of interstitial fluid increases. Detectors = osmoreceptors and firing rate affected by level of hydration located in lamina terminalis which has two circumventricular organs ovlt and sfo and are located outside. Volumetric thirst kidneys detect decreases in flow of blood to them when decreased, cells in there secrete renin which enters blood and catalyzes conversion of angiotensinogen into angiotensin. When the volume of the blood plasma falls, the atria become less full and the stretch receptors within them will detect this change. Short term carbohydrates liver - glycogen; long term reservoir - fats (triglycerides) beneath skin in adipose tissue.