The pneumotaxic center of the pons

Correct Answer: C

Rationale: The correct answer is C because the pneumotaxic center in the pons modifies the rate and depth of breathing by sending inhibitory signals to the dorsal respiratory group in the medulla, which controls inspiration and expiration. It does not set the at-rest respiratory pattern like option A, prolong inspiration like option B, or suppress the expiratory center in the medulla like option D. This center plays a crucial role in fine-tuning breathing patterns to maintain appropriate oxygen levels in the body.

Correct Answer: D

Rationale: The correct answer is D: cuneiform. The cuneiform cartilages are paired cartilages, not unpaired. The epiglottis, cricoid, and thyroid cartilages are unpaired cartilages of the larynx. The epiglottis functions in covering the larynx during swallowing, the cricoid provides support for the larynx, and the thyroid cartilage forms the "Adam's apple." The cuneiform cartilages, on the other hand, are small paired cartilages located within the aryepiglottic folds. They help maintain the shape and stiffness of these folds, assisting in vocal cord function.

Correct Answer: C

Rationale: The correct answer is C: Nasopharynx. The Eustachian tube connects the middle ear to the nasopharynx, allowing for pressure equalization. The oropharynx (A) and laryngopharynx (B) do not directly receive the Eustachian tube. Choice D is incorrect as the Eustachian tube does connect to a specific part of the pharynx.

Correct Answer: C

Rationale: The correct answer is C: When three consecutive sputum cultures are negative. This indicates successful treatment completion and eradication of the tuberculosis infection. A negative sputum culture confirms that the patient is no longer infectious and can safely discontinue the medication. Choice A is incorrect because a single negative sputum culture does not guarantee complete eradication of the infection. Choice B is incorrect as the standard treatment duration for tuberculosis is typically 6-9 months, but discontinuation should be based on sputum culture results. Choice D is incorrect as the TST can remain positive even after successful treatment, as it reflects exposure to the tuberculosis bacteria, not active infection status.

Correct Answer: A

Rationale: Carbonic anhydrase catalyzes the conversion of carbon dioxide and water to bicarbonate and hydrogen ions in the kidney. Inhibiting carbonic anhydrase reduces bicarbonate reabsorption, leading to increased excretion of bicarbonate in the urine. Therefore, the correct answer is A. Incorrect choices: B: Inhibiting carbonic anhydrase would decrease bicarbonate reabsorption, resulting in increased excretion, not decreased. C: Inhibition of carbonic anhydrase does have an effect on bicarbonate excretion. D: Inhibiting carbonic anhydrase would not increase reabsorption but rather decrease it, leading to increased excretion.