1. Define the following terms:
a. Mastication - The process of chewing.
b. Digestion - The breakdown of food molecules into their individual components.
c. Deglutition - The act of swallowing.
d. Peristalsis - The process of contraction and relaxation of circular smooth muscles which pushes food through the alimentary canal.
e. Gastric juice - The acidic secretion of the stomach.
f. Adventitia - A thin layer of loose connective tissue that binds an organ to surrounding tissues or organs.
g. Lumen - The hole in the center of a tube.
h. Macronutrients - The nutrients the body needs in large amounts: carbohydrates, fats, and proteins.
i. Micronutrients - The nutrients the body needs in small amounts, such as vitamins and minerals.
2. Label the following organs:
a. tongue
b. larynx
c. trachea
d. apncreas
e. stomach
f. small intestine
g. anus
h. salivary glands
i. salivary glands
j. salivary glands
k. pharynx
l. esophagus
m. lungs
n. liver
o. gallbladder
3. a. The tongue is part of the digestive system and part of the alimentary canal. It moves food around in the mouth.
b. The larynx is not a part of the digestive system.
c. The trachea is not a part of the digestive system.
d. The pancreas is a part of the digestive system, but not the alimentary canal. It produces digestive juices.
e. The stomach is a part of the digestive system and the alimentary canal. It churns and mixes food with gastric juices, which also help get rid of bacteria. It temporarily stores food.
f. The small intestine is a part of the digestive system and alimentary canal. It chemically digests food and allows nutrients to be absorbed through its lining.
g. The anus is a part of the digestive system and alimentary canal. It allows feces to exit the body.
h. The salivary glands are part of the digestive system, but not the alimentary canal. They produce saliva in
the mouth. They break down starch, lubricate the food, and protect the mouth.
k. The pharynx is a part of the digestive system and alimentary canal. It pushes food into the esophagus.
l. The esophagus is a part of the digestive system and alimentary canal. It pushes food to the stomach.
m. The lungs are not a part of the digestive system.
n. The liver is a part of the digestive system, but not the alimentary canal. It picks up nutrients from the blood, cleans the blood, produces bile, makes proteins from amino acids, and stores micro- and macronutrients.
o. The gallbladder is a part of the digestive system, but not the alimentary canal. It stores and concentrates bile, then releases the bile into the small intestine.
v. The large intestine is a part of the digestive system and alimentary canal. It absorbs water from the feces.
4. The epiglottis closes off the larynx when we swallow.
5. Amylase is a digestive enzyme found in saliva. It breaks down starch into maltose.
6. The soft palate closes off the nasal cavity when swallowing.
7. The four tunics of the alimentary canal are the serosa, the longitudinal muscularis, the circular muscularis, the submucosa, and the mucosa. The stomach has an extra tunic called the oblique muscularis.
8. Pepsin is a digestive enzyme secreted by the stomach. It breaks proteins down into peptides.
9. The stomach cells secrete mucus that lines the stomach, protecting it from the acidity of the gastric juice.
10. Intrinsic factor allows vitamin B12 to be absorbed by the small intestine.
11. The stomach can absorb water, alcohol, and aspirin.
12. The affects of the hormone gastrin are:
1. increases lower esophageal sphincter tone
2. decreases pyloric sphincter tone
3. increases the rate of secretion of gastric juice from the gastric pits
4. increases the rate of mixing waves of the stomach.
13. The regions of the small intestine are:
1. the duodenum
2. the jejunum
3. the ileum
The duodenum is the smallest region.
14. Circular folds, intestinal villi, and microvilli increase the rate at which nutrients are absorbed.
15. Three main hormones released by the small intestine:
1. secretin: reduces the secretion of gastric juice and increases secretion of substances which reduce acidity of chyme.
2. Cholecystokinin (CCK): causes gallbladder to contract.
((It also inhibits gastric secretion a bit and increases the secretion of digestive enzymes from the pancreas))
3. Gastric inhibitory peptide (GIP): reduces the rate at which the stomach is emptied.
16. The major enzymes in intestine juice and their functions:
1. maltose: breaks down maltose ((should be: Maltase breaks down maltose))
2. sucrase: breaks down sucrose
3. lactase: breaks down lactose
4. peptidase: breaks down peptides
5. enterokinase: activates trypsinogen into trypsin
17. Producing an active enzyme which breaks down proteins would destroy the cell.
18. Bacteria in the large intestine produce vitamin K, biotin, and folic acid, which are then absorbed by the large intestine. ((They also break down other chemicals that end up in the feces))
19. When the stomach is filled, it triggers mass movements, causing the chyme to move towards the rectum.
20. In a liver lobule, blood travels from the portal triads to the central vein. Bile flows the opposite way.
21. Bile is not a digestive enzyme. It emulsifies fats, aiding in their digestion.
22. Amylase is produced by the salivary glands and the pancreas.
23. Four secretions which reduce he acidity of chyme are alkaline mucus, intestinal juice, bicarbonate, and bile.
((alkaline mucus is from the duodenal glands, intestinal juice is from the intestinal glands, bicarbonate from pancreatic juice, and bile from the gall bladder))
24. The fat-soluble vitamins are vitamin A, vitamin D, vitamin E, and vitamin K.
25. Vitamins are regulators of the chemical processes which occur in the body.
26. The body can absorb vitamins D and K without eating food that contains those vitamins.