Bio 132 Exam 3 Questions With Complete Solutions Rated A+

Bio 132 Exam 3 Questions With Complete Solutions Rated A+ 1. Describe the difference between the alimentary canal (GI tract) and accessory organs. - Answer- Alimentary canal = tube food passes through (mouth, pharynx, esophagus, stomach, small intestine, large intestine) where digestion and absorption occur. Accessory organs = organs/glands that aid digestion (teeth, tongue, salivary glands, pancreas, liver, gallbladder). 2. List the regions of the GI tract and the accessory organs of the digestive system. - Answer- GI tract: mouth, pharynx, esophagus, stomach, small intestine, large intestine. Accessory organs: teeth, tongue, salivary glands, pancreas, liver, gallbladder. 3. Distinguish between mechanical and chemical digestion. - Answer- Mechanical = physical breakdown of food. Chemical = enzymatic breakdown into smaller compounds. 4. Identify the four layers of the wall of the digestive tract and their basic functions. - Answer- Mucosa = epithelial lining Submucosa = connective tissue Muscularis externa = muscle layer Serosa = outer covering 5. Differentiate between peristalsis and segmentation. - Answer- Peristalsis = moves material through gut Segmentation = mixes material with digestive enzymes (mainly in SI) 6. Describe the general neural and hormonal controls over digestive function. - Answer- Neural: parasympathetic ↑ GI activity ("rest & digest"), sympathetic ↓ GI activity ("fight or flight"), enteric reflexes control contractions. Hormonal: gastrin increases activity, somatostatin decreases (inhibits). 7. Describe the gross anatomy of the digestive tract from the mouth through the esophagus. - Answer- Mouth → pharynx → esophagus → stomach; includes tongue, palate, tonsils, and salivary glands. 8. Describe muscular control as food moves from the mouth to the esophagus and towards the stomach. - Answer- Swallowing: voluntary (mouth) → reflex (pharynx) → involuntary (esophagus via smooth muscle/peristalsis). 9. Describe the composition and functions of the components of saliva. - Answer- Mostly water, electrolytes, urea; mucin (lubrication), lysozyme (bacteria control), IgA/defensins (immune), salivary amylase (starch digestion) 10. Describe the neural control of salivation. - Answer- Parasympathetic ↑ salivation, sympathetic ↓ salivation; also stimulated by sight/smell. 11. Explain the extent to which digestion/absorption occurs in the mouth through the esophagus. - Answer- Mechanical digestion (chewing), chemical digestion (amylase on starch); no absorption except some drugs. 12. Contrast the structure of the gastric mucosa with that of the esophagus. - Answer- Stomach: simple columnar epithelium with gastric pits/glands. Esophagus: stratified squamous epithelium. 13. Describe the gross and microscopic anatomy of the stomach. - Answer- Gross: cardiac region, fundus, body, pyloric region. Microscopic: gastric pits/glands, simple columnar mucosa. 14. Describe how the muscularis of the stomach differs from that of the rest of the GI tract. - Answer- Stomach has 3 layers of muscle; rest of GI tract has 2. 15. List the four types of epithelial cells in the pits of the gastric mucosa. Identify the secretions and functions. - Answer- Mucus neck cells → mucus Parietal cells → HCl Chief cells → pepsinogen Enteroendocrine cells → hormones (e.g., gastrin) 16. Explain the extent to which digestion/absorption occurs in the stomach. - Answer- Mechanical mixing; protein digestion begins; limited absorption (lipid-soluble substances like alcohol, aspirin). 17. Describe the three modes by which gastric activity is regulated. Contrast cephalic, gastric, and intestinal regulation. - Answer- Cephalic: sight/smell/thought of food stimulates stomach Gastric: stomach stretch & pH changes regulate activity Intestinal: duodenum signals (chyme) inhibit or stimulate stomach 18. Differentiate among gastritis and gastric ulcers. - Answer- Gastritis = inflammation Ulcers = erosion of stomach wall (often H. pylori) 19. Describe emesis. - Answer- Vomiting caused by irritation/stretch; involves increased abdominal pressure, relaxation of cardiac sphincter. 20. Describe the gross and microscopic anatomy of the small intestine. State how mucosa differs from stomach. - Answer- Gross: duodenum, jejunum, ileum Microscopic: villi, microvilli, circular folds Difference: SI has villi for absorption; stomach does not. 21. Describe how each major class of nutrients is chemically digested. - Answer- Carbs → amylase → monosaccharides Proteins → proteases → amino acids Lipids → lipase + bile → fatty acids Nucleic acids → nucleases → bases, sugars, phosphates 22. Describe how each type of nutrient is absorbed by the small intestine. - Answer- Carbs & proteins → blood Lipids → lymph Nucleic acids → blood Vitamins: fat-soluble → lymph; water-soluble → blood 23. Describe the hormonal/neural control of the small intestine. - Answer- Hormones: gastrin, VIP Neural: parasympathetic ↑ activity, sympathetic ↓ 24. Describe the condition known as Celiac disease. - Answer- Immune reaction to gluten damaging intestinal villi → decreased absorption. 25. Describe the digestive secretions and functions of the pancreas, liver, and gallbladder. - Answer- Pancreas: enzymes + bicarbonate Liver: bile production Gallbladder: stores bile 26. Explain how hormones regulate secretions of the pancreas, the liver, and the gall bladder. - Answer- Secretin → bile production & bicarbonate CCK → gallbladder contraction ACh → pancreatic enzyme secretion 27. Differentiate among hepatitis, cirrhosis, jaundice, and gallstones. - Answer- Hepatitis = liver inflammation Cirrhosis = scar tissue Jaundice = yellowing from bilirubin Gallstones = cholesterol crystallization 28. Describe the gross and microscopic anatomy of the large intestine. Contrast the mucosa of the colon with that of the small intestine. - Answer- Gross: cecum, colon, rectum, anal canal Microscopic: simple columnar with goblet cells Difference: no villi (unlike SI) 29. State the physiological significance of intestinal bacteria. - Answer- Ferment carbs, produce gases, synthesize vitamins B & K. 30. Explain the neurological control of defecation. - Answer- Parasympathetic reflex relaxes internal sphincter; external sphincter is voluntary. 31. Differentiate among diarrhea, constipation, hemorrhoids, and appendicitis. - Answer- Diarrhea = fast movement, watery stool Constipation = slow movement, hard stool Hemorrhoids = inflamed veins Appendicitis = appendix infection