Exam 3 Study Guide - EXAM 3 STUDY GUIDE WEEK 12 Water Major...

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EXAM 3 STUDY GUIDE WEEK 12 Water Major Roles of Water o Carries nutrients throughout the body o Serves as the solvent for minerals, vitamins, amino acids, glucose, and other small molecules o Cleanses the tissues and blood of wastes o Actively participates in many chemical reactions o Acts as a lubricant around joints o Serves as a shock absorber inside the eyes, spinal cord, joints, and amniotic sac surrounding a fetus in the womb o Aids in maintaining the body’s temperature What Can Cause Dehydration? o When too much water is lost from the body and is not replaced o First sign of dehydration is thirst o Symptoms: headache, fatigue, confusion or forgetfulness, elevated heart rate How is Water Regulated in the Body? o Water needs depends on the foods a person eats, the environmental temperature and humidity, the altitude, the person’s activity level, and other factors o The water of beverages and foods meets nearly all of the need for water, and a little more is supplied by the water formed during cellular breakdown of energy nutrients o The brain regulates water intake; the brain and kidneys regulate water excretion Sources of Water Input and Output o Water Input (Total = 1450–2800 ml) Foods (700-1000 ml) Liquids (550-1500 ml) Water created by metabolism (200-300 ml) o Water Output (Total = 1450-2800 ml) Kidneys (500-1400 ml) Skin (450-900 ml) Lungs (350 ml) Feces (150 ml) Differences Between Soft and Hard Water o Soft water: water with a high sodium concentration o Hard water: water with high calcium and magnesium concentrations Minerals
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Roles of Water and Minerals in Maintaining Fluid, Electrolyte, and Acid-Base Balance o The major minerals form salts that dissolve in the body fluids; the cells direct where the salts go, and this determines where the fluids flow because water follows salt o Salts dissolve in water Electrically charged particles called ions Electrolytes o To control the flow of water, the body must spend energy moving its electrolytes from one compartment to another o The body’s proteins and some of its mineral salts help prevent changes in the acid-base balance of its fluids by serving as buffers – molecules that gather up or release H ions as needed to maintain the correct pH o The kidneys help to control the pH balance by excreting more or less acid and the lungs help by excreting more or less carbon dioxide (carbonic acid) Iodine o Main functions – A component of the thyroid hormone thyroxine, which helps to regulate growth, development, and metabolic rate o Deficiency symptoms - Goiter (simple or toxic): enlargement of the thyroid gland; cretinism: severe mental and physical retardation of an infant o Toxicity symptoms – Depressed thyroid activity; goiter-like thyroid enlargement o Sources - Iodized salt, seafood, bread, plants grown in most parts of the country and animals fed those plants Zinc o Main functions - Associated with hormones; needed for many enzymes;
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This note was uploaded on 05/27/2008 for the course HNF 150 taught by Professor Thurston during the Winter '07 term at Michigan State University.

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Exam 3 Study Guide - EXAM 3 STUDY GUIDE WEEK 12 Water Major...

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