12.1 The Digestive System
The human digestive system is an extended tube with specialized parts between two openings, the mouth and the anus.
Food is ingested and then digested to small molecules that are absorbed. Indigestible materials are eliminated.
1. What stimulates the gallbladder to release bile to the small intestine? Answer2. What are some of the ways the small intestine is adapted for increased absorption? Answer
12.2 Three Accessory Organs
The pancreas, the liver, and the gallbladder are accessory organs of digestion because their activities assist the digestive process.
3. How does the pancreas assist digestion? Answer
4. How does the liver act as "gatekeeper" to the blood? Answer
12.3 Digestive Enzymes
The products of digestion are small molecules, such as amino acids, fatty acids, and glucose, that can cross plasma membranes.
The digestive enzymes are specific and have an optimum temperature and pH at which they function.
5. Where does the digestion of carbohydrates begin in the body? Answer 6. Why is hydrochloric acid needed for digestion to occur in the stomach? Answer
12.4 Nutrition Proper nutrition supplies the body with energy, nutrients, and all vitamins and minerals.
7. Why are whole grains a healthier dietary choice than refined and milled flours? Answer8. What is the main difference between the modern diet of native Hawaiians compared with the ancient diet of the same people? Answer
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