Plicae Circularis and intestinal villi

Correct Answer: D

Rationale: The correct answer is D because Plicae Circularis and intestinal villi increase the surface area of the small intestine mucosa, aiding in absorption. Plicae Circularis are circular folds in the mucosa, while intestinal villi are finger-like projections. This increased surface area allows for more efficient absorption of nutrients. A: Incorrect. Plicae Circularis and intestinal villi do not produce new cells for the mucosa. B: Incorrect. These structures do not carry products of digestion that won't pass through blood capillaries. C: Incorrect. They do not produce hormones to aid in digestion. In summary, choice D is correct as Plicae Circularis and intestinal villi primarily function to increase the surface area of the small intestine mucosa, aiding in absorption of nutrients.

Correct Answer: C

Rationale: The correct answer is C: stomach. The stomach has 3 layers of smooth muscle in its muscularis externa, which help in mixing and churning food for digestion. The small intestine (A) has 2 layers of smooth muscle, the esophagus (B) has skeletal and smooth muscle, and the large intestine (D) has outer longitudinal and inner circular layers of smooth muscle, not 3 distinct layers like the stomach.

Correct Answer: C

Rationale: The correct answer is C because most ingested food molecules are large and need to be broken down into smaller molecules for absorption. Digestion involves the breakdown of complex nutrients into simpler forms that can be absorbed by the body. Choice A is incorrect because digestive enzymes can work on a variety of substrates, not necessarily requiring a variety. Choice B is incorrect as digestion is not primarily aimed at balancing the diet but rather extracting nutrients. Choice D is incorrect as digestion primarily occurs in the stomach and small intestine, not specifically to prevent disorders of the intestine.

Correct Answer: C

Rationale: The correct answer is C: an anticholinergic medication. Anticholinergic medications inhibit the action of acetylcholine, a neurotransmitter responsible for stimulating intestinal motility. By blocking acetylcholine, anticholinergics can effectively immobilize the intestines during surgery. Choice A (a cholinergic medication) would have the opposite effect by stimulating intestinal motility. Choice B (an antiadrenergic medication) is not directly related to immobilizing the intestines. Choice D is incorrect as only option C is the most effective at achieving intestinal immobilization.

Correct Answer: A

Rationale: The correct answer is A: esophagus. The esophagus is a muscular tube that carries food from the mouth to the stomach through a process called peristalsis. It is lined with muscles that contract to push food downward. The trachea (B) is responsible for breathing, not digestion. The nasopharynx (C) is part of the respiratory system. The epiglottis (D) is a flap of tissue that prevents food from entering the trachea during swallowing.