Which of the following epithelial types is most closely associated with passive protection, without specialization for either secretion or absorption, as in the esophagus and anal canal?

Correct Answer: B

Rationale: The correct answer is B: stratified squamous. The esophagus and anal canal are exposed to mechanical stress and abrasion, requiring a protective epithelium. Stratified squamous epithelium is ideal for this role due to its multiple layers of cells that provide durability and protection against wear and tear. Simple squamous epithelium (choice A) is too thin and fragile for this function. Simple columnar epithelium (choice C) is specialized for secretion and absorption, not for protection. Stratified columnar epithelium (choice D) is relatively rare in the body and not typically found in areas requiring high protection like the esophagus and anal canal.

Correct Answer: D

Rationale: The correct answer is D: pancreas. Pancreatic tissue is often poorly preserved in autopsy specimens due to the post-mortem release of its stored secretory product, which is a highly concentrated mixture of proteolytic enzymes. These enzymes can rapidly degrade the pancreatic tissue itself, leading to self-destruction soon after death. This phenomenon is known as autolysis. Submaxillary and sublingual glands (choice A), esophageal glands (choice B), and duodenal (Brunner's) glands (choice C) do not typically release such high concentrations of proteolytic enzymes upon death, leading to better preservation in autopsy specimens compared to pancreatic tissue.

Correct Answer: A

Rationale: The correct answer is A. The thickness of the stomach wall (all layers) is about 1-2 millimeters. This includes the mucosa, submucosa, muscularis, and serosa layers, which together make up the entire thickness of the stomach wall. The other choices are incorrect because: B. The thickness of the gastric mucosa is much thinner than 1-2 millimeters. C. The height of the stomach's surface epithelial cells is a microscopic measurement, not in the millimeter range. D. The diameter of a parietal cell is also a microscopic measurement, not in the millimeter range. Therefore, the correct answer is A based on the actual dimensions of the structures mentioned in the question.

Correct Answer: D

Rationale: The correct answer is D because epithelial cells lining striated intralobular ducts are usually simple cuboidal or columnar cells (A), have eosinophilic cytoplasm containing numerous mitochondria for energy production (B), and have basal cell membranes extensively folded to increase the surface area for active ion pump molecules (C). Choice A describes the cell morphology, choice B relates to cytoplasm content, and choice C pertains to membrane structure, all of which are characteristics of these cells. Therefore, selecting all three choices (D) accurately describes the features of epithelial cells in striated intralobular ducts.

Correct Answer: D

Rationale: The correct answer is D: absorbing nutrients. Enterocytes in the small intestine are primarily responsible for absorbing nutrients from digested food. They have specialized structures like microvilli to increase surface area for absorption. Choice A is incorrect because enterocytes do not secrete digestive enzymes; that is done by other cells in the small intestine. Choice B is incorrect because hormone secretion is mainly done by endocrine cells in the intestine. Choice C is incorrect because goblet cells are responsible for secreting mucus in the intestine, not enterocytes. In summary, enterocytes' main function is to absorb nutrients, not secrete enzymes, hormones, or mucus.