Section 2 Workbook (units 4, 5 & 6)

Transcription

1 Section 2 Workbook (units 4, 5 & 6) Name: Key KeyANANSWERAN AN C1. Analyze the functional inter-relationships of the structures of the digestive system. 1. A) Complete the table ANSWERS Digestive System mouth tongue teeth Structure salivary glands pharynx epiglottis esophagus cardiac sphincter stomach p yloric sphincter duodenum gall bladder pancreas small intestine appendix large intestine (colon) rectum anus Ingest food Function Push food between the teeth; form the bolus; speech; taste; and spread saliva Mechanical digestion; break food into smaller pieces for enzymes to act upon Produces salivary amylase to start the digestion of carbohydrates (starch to maltose) Muscular to push the bolus down the esophagus Prevents food and drink from going down the esophagus Directs food from the pharynx to the stomach by peristalsis Controls what enters the stomach and prevents chyme from entering the esophagus Mechanical digestion by churning food. Chemical digestion by pepsin to change proteins into peptides Slowly releases chyme into the duodenum Where the majority of digestion occurs final digestion of all macromolecules into monomers. Receives enzymes from pancreas and wall of duodenum. Stores bile until it is needed to emulsify fats Regulates blood sugar levels with the hormones insulin and glucagon. Neutralizes chyme (sodium bicarbonate) and makes enzymes for digestion SALT + N First part = duodenum where majority of chemical digestion occurs to create monomers. Last part is for absorption of monomers in the villi & microvilli Lymph tissue to fight infection Absorbs mainly water. Also absorbs salts. Has E. coli to make vitamins, growth factors, and folic acid. Stores feces until elimination Sphincter muscle for the release of feces -1-

2 B) Label all structures from the previous table on these diagrams. Salivary glands Liver Small Intestine Large Intestine (colon) Stomach Pancreas Bile duct Small intestine (duodenum) Pancreas Stomach 2. Describe swallowing. A reflex where the pharynx pushes the bolus to the esophagus and then, by peristalsis, the bolus is moved to the stomach 3. Describe peristalsis It is a wave of muscular contraction that moves food along the digestive tract. 4. What is the source gland for insulin? Pancreas 5. How does insulin maintain blood sugar levels? It is a hormone that causes the cells of the body to take up glucose from the blood to decrease the blood glucose levels -2-

3 6. Describe at least six functions of the liver. BBBBBB U 1 Makes bile Breaks down and recycles old red blood cells Makes blood proteins ex) albumin & fibrinogen Monitors the blood nutrient levels Makes urea Regulates blood sugar levels with insulin and glucagon Detoxifies blood ex) turns alcohol into fatty acids 7. Explain the role of bile in the digestion of fats. Emulsifies fats break fats into fat droplets (smaller pieces) 8. How is the small intestine specially designed for each of the following tasks? a. Chemical digestion Mucus to prevent digestion of the small intestine; glands to make intestinal juice with digestive enzymes; and an opening for receiving enzymes from the pancreas b. Physical digestion Opening to receive bile from the gall bladder to emulsify fats c. Absorption It has villi & microvilli to increase the surface area for absorption. It also is very long to allow for time needed for absorption of nutrients to occur 9. Describe and label the structures in this villus. Include the functions of the microvilli, Trace the path way of all digestion products in to the villus. Microvilli increase the surface area for absorption of nutrients and also release enzymes. Lacteal absorbs glycerol and fatty acids Blood capillaries absorb all other monomers -3-

4 10. Describe the functions of anaerobic bacteria in the colon. They make vitamins, growth factors, and break down waste / feces (create the smell) C2. Describe the components, ph, and digestive actions of salivary, gastric, pancreatic, and intestinal juices. 11. A) Complete the table. Enzyme salivary amylase pancreatic amylase Optimal Reaction Catalyzed Source Gland ph substrate + H 2O product 7 Salivary glands Starch + water maltose 8.5 Pancreas Starch + water maltose pepsinogen/pepsin 2.5 Gastric glands in stomach wall Protein + water peptides trypsin lipase 8.5 Pancreas Protein + water peptides 8.5 Pancreas Lipid + water glycerol + fatty acids peptidase maltase 8.5 Intestinal glands in wall of duodenum 8.5 Intestinal glands in wall of duodenum Peptides + water amino acids Maltose + water 2 glucose molecules nuclease 8.5 Pancreas Nucleic acids + water nucleotides nucleosidases 8.5 Intestinal glands in wall of duodenum Nucleotides + water sugar, N-base, phosphate B) Why is the enzyme pepsinogen secreted in an inactive form? What activates it? So the stomach wall is not digested because it is a big protein bag. Pepsinogen is converted into pepsin by hydrochloric acid - HCl -4-

5 12. Draw a graph to show the enzyme activity of pepsin and trypsin at various ph. Explain why the curves are different. Curves are different because the optimal ph for the enzymes is dependent upon where it is released and acts in the body. 13. What is the importance of the ph level in the various regions of the digestive tract? It is the optimal ph for enzymes to work at peak efficiency enzymes have an optimal ph based upon where they act in the body 14. Describe in detail the role of each of these substances. Component water in digestive juices Role Hydrolysis necessary for the hydrolytic enzymes to work. sodium bicarbonate in pancreatic juice 2 functions hydrochloric acid (HCl) in gastric juice 3 functions mucus in gastric juice 2 functions Neutralizes the chyme from the stomach & raises the ph to 8.5 so that the small intestine enzymes will function Kills bacteria and pathogens, activates pepsinogen into pepsin, denatures salivary amylase Protects the lining of the digestive tract from enzymatic reactions and keeps the food moving through the digestive tract -5-

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