The epithelium of the mouth, oropharynx, esophagus and anal canal is

Correct Answer: B

Rationale: The correct answer is B: stratified squamous. The epithelium of the mouth, oropharynx, esophagus, and anal canal is stratified squamous because these areas are subject to mechanical stress and friction. Stratified squamous epithelium provides protection against abrasion and wear. Simple squamous (A) is found in areas involved in filtration like the kidneys. Simple columnar (C) is found in the intestines for absorption. Pseudostratified columnar (D) is typically found in the respiratory tract to help with mucus production and movement.

Correct Answer: C

Rationale: The correct answer is C: mucus. The esophagus secretes mucus to facilitate the passage of food from the mouth to the stomach, providing lubrication and protection to the esophageal lining. Bile (A) is produced by the liver and stored in the gallbladder, amylase (B) is an enzyme produced by the pancreas to break down carbohydrates in the small intestine, and hydrochloric acid (D) is produced by the stomach to aid in digestion. None of these substances are major secretions of the esophagus.

Correct Answer: A

Rationale: Rationale: 1. Gastrin is released by the stomach to stimulate gastric acid secretion. 2. Gastrin is also released by the small intestine to regulate digestive processes. 3. Secretin is released by the small intestine to stimulate bicarbonate secretion. 4. Cholecystokinin is released by the small intestine to stimulate bile release. 5. Gastric inhibitory polypeptide is released by the small intestine to inhibit gastric acid secretion. Summary: A: Gastrin is the correct answer as it is released by both the stomach and small intestine. B: Secretin is only released by the small intestine. C: Cholecystokinin is only released by the small intestine. D: Gastric inhibitory polypeptide is only released by the small intestine.

Correct Answer: C

Rationale: The correct answer is C because cholecystokinin inhibits gastric secretions, stimulates pancreatic secretions high in enzymes, and stimulates contraction of the gall bladder and relaxation of the sphincter of Oddi. This hormone is released in response to the presence of fats and proteins in the small intestine, leading to the digestion and absorption of these nutrients. Choices A and B are incorrect as they do not fully capture the wide range of effects of cholecystokinin. Choice D is also incorrect because it includes the stimulation of bile secretion, which is not a direct effect of cholecystokinin.

Correct Answer: C

Rationale: The correct answer is C: brush border of the small intestine. Disaccharides are broken down into monosaccharides by specific enzymes located in the brush border of the small intestine. These enzymes include sucrase, lactase, and maltase. The breakdown of disaccharides into monosaccharides occurs in the final stage of carbohydrate digestion, allowing for absorption into the bloodstream. Choices A, B, and D are incorrect because disaccharides are not primarily digested in the stomach, the lumen of the small intestine, or the colon. The main site for disaccharide digestion is the brush border of the small intestine where these specific enzymes are located.