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Anatomy Chapter 2 Vocab

Terms in this set (114)

is the most abundant inorganic compound in the body. It accounts for about two-thirds of body weight. Body tissues are 60 to 80 percent water. Among the properties that make water so vital are the following:
1. High heat capacity. Water has a high heat capacity; that is, it absorbs and releases large amounts of heat before its temperature changes appreciably. Thus, it prevents the sudden changes in body temperature that might otherwise result from intense sun expo- sure, chilling winter winds, or internal events (such as vigorous muscle activity) that liberate large amounts of heat.
2. Polarity/ solvent properties. Because of its polarity, water is an excellent solvent; indeed, it is often called the "universal solvent." A solvent is a liquid or gas in which smaller amounts of other substances, called solutes (which may be gases, liquids, or solids), can be dissolved or suspended. The resulting mixture is called a solution when the solute particles are exceedingly tiny, and a suspension when the solute particles are fairly large. Translucent mixtures with solute particles of intermediate size are called colloids.
3. Chemical reactivity. Water is an important reactant in some types of chemical reactions. For example, to digest foods or break down biological molecules, water molecules are added to the bonds of the larger molecules. Such reactions are called hydrolysis reactions, a term that specifically recognizes this role of water (hydro= water; lys = splitting).
4. Cushioning. Water also serves a protective function. In the form of cerebrospinal fluid, water forms a cushion around the brain that helps to protect it from physical trauma. Amniotic fluid, which surrounds a developing fetus within the mother's body, plays a similar role in protecting the fetus.