Which of the following is FALSE about the enteric nervous system?

Correct Answer: D

Rationale: Correct Answer: D Rationale: 1. The enteric nervous system can autonomously regulate digestive functions locally without input from the central nervous system. 2. Enteric sensory and motor neurons are key components of the enteric nervous system, responsible for detecting stimuli and coordinating gut movements. 3. Enteric interneurons play a crucial role in connecting sensory and motor neurons within the enteric nervous system. 4. Choice D is false because the enteric neurons are capable of controlling digestive tract functions independently from the central nervous system.

Correct Answer: B

Rationale: The correct answer is B: pulp cavity; root canal. The pulp cavity is the center of the tooth filled with blood vessels and nerves, while the root canal is the cavity within the root of the tooth. This is because the pulp cavity contains the pulp tissue, which includes blood vessels and nerves, providing nourishment and sensation to the tooth. The root canal, on the other hand, is the space within the root where the pulp tissue extends down into. Choices A, C, and D are incorrect because they do not accurately describe the specific structures mentioned in the question.

Correct Answer: D

Rationale: The correct answer is D: sublingual gland. This gland primarily produces mucus, aiding in lubrication and initial digestion. The sublingual gland is located under the tongue. A: The parotid gland primarily produces serous saliva. B: Labial glands are minor salivary glands located in the lips, producing mixed saliva. C: Submandibular gland produces a mixture of serous and mucous saliva.

Correct Answer: A

Rationale: The correct answer is A: gastric pits. Gastric pits are invaginations in the stomach lining that contain specialized cells for secretion of gastric juices. These pits increase the surface area of the stomach by providing a larger area for nutrient absorption and digestion. Plicae circulares are folds in the small intestine, not the stomach. Villi and microvilli are found in the small intestine and further increase surface area for absorption, not in the stomach.

Correct Answer: B

Rationale: The correct answer is B because the low pH of the stomach activates pepsin, an enzyme that digests proteins, while inactivating salivary amylase, an enzyme that digests starch. Pepsin works optimally in an acidic environment, breaking down proteins into peptides. Salivary amylase, on the other hand, works best at a neutral pH and is denatured in the acidic stomach, leading to its inactivation. Choices A, C, and D are incorrect because lipids are primarily digested in the small intestine, and nucleic acids are not directly affected by the stomach's pH.