The esophagus pierces through an opening in the diaphragm called the

Correct Answer: B

Rationale: The correct answer is B: hiatus. The esophagus pierces through an opening in the diaphragm called the esophageal hiatus. The hiatus allows the esophagus to pass from the thoracic cavity into the abdominal cavity. The other choices are incorrect because: A: Fauces is the opening at the back of the mouth leading to the pharynx. C: Glottis is the part of the larynx consisting of the vocal cords and the opening between them. D: Inguinal canal is a passage in the abdominal wall near the groin.

Correct Answer: B

Rationale: The correct answer is B: calcium. The liver stores copper, iron, vitamins A, B12, D, E, and K, and glycogen. Calcium is primarily stored in bones and teeth, not in the liver. The liver's main functions are to regulate blood sugar levels, detoxify the body, produce bile, and store essential nutrients and energy sources. Calcium is mainly stored in the bones and teeth for structural support and plays a crucial role in muscle function, nerve transmission, and blood clotting. Therefore, the liver does not serve as a major storehouse for calcium.

Correct Answer: B

Rationale: The correct answer is B: inhibit the defecation reflex. Stimulation of the internal anal sphincters by the sympathetic nervous system or stimulation of the external anal sphincter by the somatic motor nervous system leads to constriction of the anal sphincters, preventing the passage of feces. This inhibits the defecation reflex by maintaining continence. The other choices are incorrect because: A: Stimulating the anal sphincters does not promote the defecation reflex; it actually inhibits it. C: Mass movements are related to the movement of feces through the large intestine, not directly influenced by anal sphincter stimulation. D: Inhibiting mass movements is not a direct effect of anal sphincter stimulation.

Correct Answer: A

Rationale: The correct answer is A because it accurately states that the products of protein digestion can be absorbed as free amino acids or as di- or tripeptides. This is true as the final breakdown products of proteins, whether they are individual amino acids or smaller peptide chains, can be absorbed through the intestinal wall into the bloodstream. Choice B is incorrect because not all proteins are digested equally in the stomach, and the efficiency of digestion can vary based on factors like protein structure and presence of inhibitors. Choice C is incorrect because chymotrypsin, elastase, and carboxypeptidase A are actually produced and secreted by the pancreas, not the gastric zymogenic cells. Choice D is incorrect because there are more than 14 different amino acid transporters involved in the absorption of digested protein products, not just one. Therefore, choice A is the most correct statement regarding protein digestion and absorption.

Correct Answer: B

Rationale: Correct Answer: B Rationale: - Brunner's glands secrete an alkaline mucous-rich fluid for protection, not digestive enzymes. - A is correct as Brunner's glands are found in the duodenal wall. - C is correct as they are located in the submucosal layer. - D is correct as they empty secretions into the crypts of Lieberkuhn, aiding in digestion.