Sometimes when you are talking and eating you initiate the gagging reflex. The gagging or coughing reflex is stimulated when foreign material enters the larynx. Some of the bolus you are swallowing enters the larynx when you are talking because the

Correct Answer: A

Rationale: The correct answer is A: epiglottis is not closed over the glottis. When talking and eating simultaneously, the epiglottis fails to close over the glottis, leading to some of the food or liquid entering the larynx instead of being directed towards the esophagus. The epiglottis normally acts as a lid to cover the larynx during swallowing, preventing food or liquid from entering the airway. Therefore, failure of the epiglottis to close properly during talking and eating can trigger the gagging reflex. Summary of why the other choices are incorrect: B: Soft palate moving inferiorly is associated with the process of swallowing and closing off the nasopharynx, not the larynx. C: Pharyngeal constrictor muscles relax would not lead to food entering the larynx during talking and eating; in fact, they contract to propel food downwards. D: Esophageal sphinct

Correct Answer: A

Rationale: The correct answer is A: cholesterol. Gallstones are primarily formed from the precipitation of cholesterol in the gallbladder due to imbalances in bile components. Cholesterol stones are the most common type of gallstones. Calcium salts (B) can contribute to gallstone formation but are not the primary component. Uric acid salts (C) are associated with kidney stones, not gallstones. Urea (D) is a waste product excreted in urine and is not involved in gallstone formation.

Correct Answer: C

Rationale: The correct answer is C: bile salts; lipase. Bile salts emulsify lipids by breaking them down into smaller droplets to increase the surface area for digestion by lipase. Lipase is the enzyme responsible for digesting lipids into fatty acids and glycerol. Option A is incorrect because lipase digests lipids, not bile salts. Option B is incorrect because amylase digests carbohydrates, not lipids. Option D is incorrect because pepsin is an enzyme that digests proteins, not lipids.

Correct Answer: A

Rationale: The correct answer is A because mucous cells in the stomach lining secrete the glycoprotein mucin, which helps protect the stomach lining from the acidic environment and digestive enzymes. This is crucial for maintaining the integrity of the stomach wall and preventing damage. Chief cells (option B) secrete pepsinogen, not gastrin. Parietal cells (option C) secrete hydrochloric acid and intrinsic factor, not pepsinogen. G cells (option D) secrete gastrin, a hormone that stimulates acid secretion but do not secrete hydrochloric acid directly. Therefore, option A is correct as it accurately describes the function of mucous cells in the stomach lining.

Correct Answer: B

Rationale: The correct answer is B because during the teen years, the brain undergoes significant changes in neural connections. New connections are formed through processes like synaptic pruning, which strengthens important connections and eliminates unnecessary ones. This dynamic phase is crucial for learning and adapting to new experiences. Choices A, C, and D are incorrect because neural networks in the brain are not static and unchanging. The brain continues to reorganize and adapt throughout life, with myelination increasing to improve signal transmission efficiency, not decreasing as in choice D. Choice C is also incorrect as brain size does not significantly increase during the teen years, but rather the focus is on optimizing existing neural connections.