List some factors that influence plasma cholesterol levels. Also list the sources and fates of cholesterol in the body.
Factors influencing plasma cholesterol levels include diet (through intake of cholesterol and/or saturated fatty acids), smoking, drinking, and stress. Sources of cholesterol in the body include the intake of animal foods and production from acetyl coenzyme A in the liver (and intestinal cells). Cholesterol is lost from the body when it is catabolized and secreted in bile salts that are eventually excreted in feces. It is used by body cells in plasma membranes and in synthesizing vitamin D and steroid hormones. (p. 944)