The salivary gland which is mixed but produces more serous than mucous secretions and whose duct opens inferiorly in the floor of the oral cavity next to the frenulum of the tongue is the ______ salivary gland.

Correct Answer: A

Rationale: The correct answer is A: submandibular gland. This gland is mixed but predominantly serous, with a duct opening in the oral cavity floor near the frenulum of the tongue. The sublingual gland (B) is primarily mucous, not mixed. Palatine glands (C) are located in the roof of the mouth and are minor salivary glands. The parotid gland (D) is serous but opens into the oral cavity through the parotid duct, not near the frenulum.

Correct Answer: A

Rationale: The correct answer is A: Kupffer cells. Kupffer cells are specialized macrophages found in the liver that play a crucial role in immune defense. They are responsible for destroying bacteria and foreign material absorbed by the small intestine as they pass through the hepatic sinusoids. Kupffer cells phagocytize these pathogens, preventing their entry into the bloodstream. The other choices, B: hepatic, C: endothelial, and D: acinar, do not have the specific function of destroying bacteria in the hepatic sinusoids. Hepatic cells are liver cells, endothelial cells line blood vessels, and acinar cells are found in exocrine glands.

Correct Answer: A

Rationale: The correct answer is A: appendicitis. Sudden abdominal pain, fever, loss of appetite, and nausea are classic symptoms of appendicitis. The pain often starts near the belly button and migrates to the lower right abdomen, where the appendix is located. Appendicitis is a medical emergency that requires immediate attention to prevent complications like a burst appendix. Heartburn (B) typically presents with a burning sensation in the chest, and diarrhea (C) presents with loose, watery stools. Hemorrhoids (D) are swollen blood vessels in the rectum that cause discomfort but do not typically present with the symptoms described.

Correct Answer: D

Rationale: The correct answer is D because pepsinogen and gastric lipase are indeed two enzymes secreted into the lumen of the stomach. Pepsinogen is converted to pepsin, an enzyme that breaks down proteins, while gastric lipase helps in the digestion of fats. A is incorrect because carbonic anhydrase is not a hormone but an enzyme involved in acid secretion. B is incorrect because Peyer's patches are actually found in the small intestine, not the stomach, and they are involved in the immune system. C is incorrect because the vagus nerve stimulates, rather than inhibits, acid secretion in response to a meal. In summary, D is correct as it accurately describes enzymes secreted in the stomach, while the other choices contain factual inaccuracies about stomach function.

Correct Answer: A

Rationale: The correct answer is A because pancreatic juice contains Trypsin for protein digestion, Amylopsin for carbohydrate digestion, and Steapsin for fat digestion. Trypsin breaks down proteins into peptides, Amylopsin breaks down carbohydrates into sugars, and Steapsin breaks down fats into fatty acids and glycerol. Pepsin, Rennin, and Gastric Lipase (option B) are enzymes found in the stomach, while Erepsin, Invertase, and Lipase (option C) are enzymes found in the small intestine. Ptyalin, Maltase, and Lactase (option D) are enzymes involved in digestion but are not found in pancreatic juice.