digestive+system+review+DW

Digestive System Review 1. Argue that absorption is the most important of the five processes of digestion over the other four processes. (144-45) Absorption is the most important part of the five processes of digestion. Simply because it is the only part that brings molecules and nutrients into the body. It is the process that bring nutrients into the cells lining the GI tract. Those cells then go throughout the body and go where they are needed. 2. List the main organs of the digestive tract and state the contribution of each to the digestive process. (146-54) The Mouth- Mechanically breaks down the food with teeth, but the enzymes in the saliva also break food down but chemically. The Esophagus- Does not contribute to the chemical break down of food. It is simply responsible for bringing the bolus to the stomach, which is called peristalsis. The Stomach- the stomach is connected to the esophagus and the small intestine. "The stomach stores food, initiates the digestion process of protein, and controls the movement of chyme into the small intestine." Absorb alcohol not nutrients The Liver- the liver acts as a sewage plants and detoxifies the blood that comes from the GI tract. Gallbladder- The gallbladder stores bile, and is connected to the liver The Pancreas- the pancreas produces pancreatic juice which contains sodium bicarbonate and digestive enzymes. the sodium bicarbonate is a base so in neutralizes acid from the stomach. Small Intestine- it accepts bile and enzymes from pancreatic juice. The small intestine also absorbs nutrients, "molecules namely sugars, amino acids, fatty acids, and glycerol. The Appendix- in humans the appendix plays a role in fighting infections, and it is connected to the large intestine. Large Intestine- the large intestine absorbs water to prevent dehydration, but does not produce digestive enzymes or absorbs nutrients from food. It absorbs vitamins from bacteria called intestinal flora. The large intestine also forms feces which is a key part of defecation.

3. Name the enzymes involved in the digestion of starch, protein, and fat, and tell where these enzymes are active and what they do. (151) Carbohydrates (starch) Salivary Amylase-Mouth Pancreatic Amylase- Small Intestine Maltase- Small Intestine Starch is digested into glucose the glucose goes into the cells which them move about the body. Protein Pepsin-Stomach Trypsin-Small Intestine Peptidases-Small Intestine Proteins are digested into amino acids. Those amino acids are sent into intestinal villi cells and transported around the body Fat Lipase-Small intestine Fats are emulsified by the bile and turned into fatty acids. 4. Why are the pancreas, liver, and gall bladder considered accessory organs of digestion and not an organ of digestion? (152) Because they are three separate organs they need one another. they are very closely connected and they send secretions to the duodenum via ducts. 5. What is the chief contribution of each of these in the body--carbohydrates, proteins, and lipids (fats)? (158-59) Carbohydrates- They are used as an energy source Proteins-"Sufficent proteins are needed to supply the essential amino acids. Lipids- there are essential fatty acids that are necessary for life, and they come through diet.

Do the multiple choice on page 167-68. Just write the number and your answer. 9) Switch E and D 10) A 11) B 12) E 13) C 14) A 15) B 16) E 17) D 18) D 19) D 20) E 21) C 22) E 23) B 24) C 25) D 26) A 27) A 28) B 29) C
 * 1) 9 to 29.