Lymphatic vessels within intestinal villi, which transport lipids to the circulatory system, are called:

Correct Answer: D

Rationale: The correct answer is D: lacteals. Lacteals are lymphatic vessels found within intestinal villi that absorb dietary lipids and transport them to the circulatory system. They play a crucial role in the absorption of fats. Capillaries (A) are small blood vessels, ductules (B) are small ducts, and canaliculi (C) are small channels within tissues. These structures do not specifically transport lipids from the intestines to the circulatory system like lacteals do.

Correct Answer: C

Rationale: The correct answer is C: small intestine. The small intestine is characterized by permanent folds called plicae circulares, which increase the surface area for nutrient absorption. These folds help to slow down the passage of food and increase contact with the intestinal walls. The other choices are incorrect because the esophagus (A) does not have permanent folds, the stomach (B) has rugae (temporary folds), and the large intestine (D) has haustra (pouches), not permanent folds like the small intestine.

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.