BY 32 – SPRING 2000

Section 2412

EXAM 1

NAME ___________________________________

Instructions: Record your answers directly on this sheet by circling the correct response. For each question, choose the single best response.

1. In reference to homeostasis, the internal environment refers to: (C)

a. the internal spaces within organs like the lumen of the GI tract.

b. internal spaces within the body like the peritoneal cavity.

c. extracellular fluids.

d. all of the above.

2. Blood pressure is one example of a physiological variable that is subject to negative feedback control. In this negative feedback loop, the baroreceptors represent which of the following components? (B)

a. The physiological variable

b. The sensor

c. The feedback controller

d. The effector

3. In a positive feedback system, the effectors cause changes in the physiological variable which: (A)

a. reinforce the initial disturbance.

b. oppose the initial disturbance.

c. cause the variable to return to its set-point.

d. both b and c.

4. A general term for a regulatory molecule that once secreted, interacts with a receptor on its own cell surface is: (A)

a. an autocrine substance.

b. a paracrine substance.

c. a hormone.

d. a neuroendocrine substance.

5. Hormone secretion can be regulated by different stimuli. An example of hormones that are controlled by neural stimuli is: (D)

a. the parathyroid hormone.

b. the thyroid hormones.

c. the anterior pituitary hormones.

d. the catecholamines.

6. Besides steroid hormones, which of the following hormones interact with receptors located in the nucleus of target cells? (B)

a. The parathyroid hormone

b. The thyroid hormones

c. The anterior pituitary hormones

d. The catecholamines

7. Following receptor activation by the hormone ADH (antidiuretic hormone), the enzyme that is responsible for cleaving PIP₂ into IP₃ (inositol triphosphate) and DAG (diacylglycerol) is called: (D)

a. protein kinase A.

b. adenylate cyclase.

c. protein kinase C.

d. phospholipase C.

8. The portion of the pituitary gland which releases hormones referred to as “anterior pituitary hormones” is called the: (A)

a. adenohypophysis.

b. neurohypophysis.

c. pars nervosa.

d. infundibulum.

9. The accessory GI organ that stores bile is called: (B)

a. the pancreas.

b. the gallbladder.

c. the parotid.

d. the vermiform appendix.

10. The process by which nutrient molecules are taken up from the GI tract lumen across the epithelium is called: (C)

a. digestion.

b. secretion.

c. absorption.

d. reabsorption.

11. An over-accumulation of peritoneal fluid is a condition referred to as: (D)

a. gingivitis.

b. peritonitis.

c. gastritis.

d. ascites.

12. In addition to the epithelium and muscularis mucosa, the other layer that forms a portion of the mucosa is called the: (C)

a. submucosa.

b. adventitia.

c. lamina propria.

d. serosa.

13. The ileocecal sphincter is formed by a thickening of the: (B)

a. muscularis mucosa.

b. inner circular layer of the muscularis externa.

c. outer longitudinal layer of the muscularis externa.

d. serosa.

14. A speech impediment known as ankyloglossia results from a malformed: (A)

a. lingual frenulum.

b. labial frenulum.

c. uvula.

d. soft palate.

15. The tongue is subdivided into two portions called the anterior 2/3s and posterior 1/3 by a structure called the: (C)

a. lingual frenulum.

b. uvula.

c. sulcus terminalis.

d. vestibule.

16. Which of the following best describes the histology of the upper 1/3 of the esophagus? (C)

a. The epithelium is stratified squamous, and the muscularis externus is exclusively smooth muscle.

b. The epithelium is simple columnar, and the muscularis externus is exclusively skeletal muscle.

c. The epithelium is stratified squamous, and the muscularis externus is exclusively skeletal muscle.

d. The epithelium is simple columnar, and the muscularis externus is exclusively smooth muscle.

17. Which of the following structures disappears upon distension of the stomach? (D)

a. The gastric pits

b. The gastric glands

c. The plicae circulares

d. The rugae

18. Of the various regions of the stomach, the histology of the fundus of the stomach most closely resembles the: (B)

a. cardiac portion of the stomach.

b. body of the stomach.

c. pyloric region of the stomach.

d. esophagus.

19. The cell type responsible for secretion of intrinsic factor is the: (D)

a. enteroendocrine cell.

b. chief cell.

c. Paneth cell.

d. parietal cell.

20. Brunner’s glands are found in the: (C)

a. esophagus.

b. stomach.

c. small intestine.

d. large intestine.

21. Within the small intestine, lymph capillaries called lacteals are found in which of the following layers? (A)

a. The lamina propria

b. The submucosa

c. The muscularis externa

d. The serosa

22. Among the structures within the small intestine, which of the following serve to increase the surface area of contact between the epithelium and the luminal contents? (D)

a. Microvilli

b. Villi

c. Plicae circulares

d. All of the above

23. Within the large intestine, the longitudinal layer of the muscularis externa is organized into three longitudinal bands called: (C)

a. haustra.

b. epiploic appendages.

c. teniae coli.

d. the greater omentum.

24. The histology of the vermiform appendix most closely resembles that of the: (D)

a. esophagus.

b. stomach.

c. small intestine.

d. large intestine.

25. The process of chemical digestion begins in the mouth with the action of: (A)

a. amylase.

b. pepsin.

c. gastrin.

d. mucus.

26. The bicarbonate concentration of saliva is increased by the activity of: (D)

a. serous acinar cells.

b. mucous acinar cells.

c. intercalated duct cells.

d. striated duct cells.

27. Compared to baseline secretion rates, maximum parasympathetic stimulation will cause amylase secretion into saliva to: (A)

a. increase.

b. remain unchanged.

c. decrease.

28. During the oral phase of swallowing, (A)

a. the upper esophageal sphincter is closed.

b. a peristaltic wave is generated in the esophagus.

c. the lower esophageal sphincter is open.

d. all of the above.

29. During the esophageal phase of swallowing, (D)

a. a peristaltic wave conducts along the esophagus.

b. the upper esophageal sphincter is closed.

c. the lower esophageal sphincter opens just before food enters the stomach.

d. all of the above.

30. The vago-vagal reflex affecting gastric secretion is initiated by: (A)

a. distension of the stomach.

b. caffeine.

c. distension of the duodenum.

d. a low stomach pH (that is pH < 2).

31. Gastrin secretion is inhibited by: (D)

a. the presence of partially digested proteins in the stomach lumen.

b. caffeine.

c. a neutral pH (that is a pH = 7).

d. excessive acidity (that is pH < 2).

32. Maximum secretion of stomach acid by parietal cells requires the simultaneous presence of acetylcholine (ACh), gastrin, and (C)

a. cholecystokinin (CCK).

b. secretin.

c. histamine.

d. vasointestinal peptide (VIP).

33. The hormone with the most potent inhibitory effect on gastric emptying is: (B)

a. gastrin.

b. CCK.

c. secretin.

d. gastric inhibitory peptide (GIP).

34. The proteolytic enzymes of the pancreas are released into the duodenum in inactive form. The first step in their activation involves: (C)

a. the formation of chymopepsin in the presence of stomach acid.

b. the formation of chymotrypsin from trypsin.

c. the conversion of trypsinogen to trypsin by an enzyme called enterokinase.

d. interaction with intrinsic factor.

35. Secretin is released from enteroendocrine cells of the small intestine in response to: (B)

a. parasympathetic stimulation.

b. acidic chyme in the duodenum.

c. chyme containing amino acids and fatty acids in the duodenum.

d. bicarbonate in the small intestine.

36. CCK acts on the: (B)

a. gallbladder causing it to relax.

b. sphincter of Oddi causing it to relax.

c. hepatocytes causing them to increase bicarbonate production.

d. the pancreas to increase bicarbonate production.

37. During the defecation reflex, (D)

a. stretch receptors in the rectum activate sympathetic nerves.

b. the internal anal sphincter contracts.

c. the intra-abdominal pressure decreases.

d. the final phase involves conscious relaxation of the external anal sphincter.

38. Bile salts act to: (A)

a. emulsify fats.

b. break down lipids into fatty acids and glycerol.

c. inhibit micelle formation.

d. all of the above.

39. Lactose intolerance involves a lack of: (B)

a. lactose.

b. lactase.

c. glucose.

d. amylase.

40. Most water absorption takes place in the: (C)

a. esophagus.

b. stomach.

c. small intestine.

d. large intestine.