Chapter 23: At a Glance Nutrition The primary sources of energy are carbohydrates and fats. Lipids include fats, phospholipids, and cholesterol. Carbohydrates, including sugars and starches, are a source of quick energy. Proteins, composed of amino acids, perform a wide range of functions within the body. Minerals are elements and small inorganic molecules required by the body. Vitamins are required in small amounts and play many roles in metabolism. Nutritional guidelines help people obtain a balanced diet. The Challenge of Digestion Human Digestion The mechanical and chemical breakdown of food begins in the mouth. The esophagus conducts food to the stomach, where digestion continues. Most digestion occurs in the small intestine. Most absorption occurs in the small intestine. Water is absorbed and feces are formed in the large intestine. Digestion is controlled by the nervous system and hormones. The Functions of the Urinary System The Human Urinary System Urine is formed in the kidneys. Blood is filtered by the glomerulus. The blood filtrate is converted to urine in the nephron. The loop of Henle allows urine to become concentrated. The kidneys are important organs of homeostasis. Designed in cooperation with Andrew Stull and Steven Brunasso. Last Update - July 25, 1997
Designed in cooperation with Andrew Stull and Steven Brunasso. Last Update - July 25, 1997
Last Update - July 25, 1997