Pneumotaxic center is

Correct Answer: A

Rationale: The correct answer is A: Inhibitory. The pneumotaxic center is located in the upper pons and functions to inhibit inspiration, preventing overinflation of the lungs. This helps regulate the respiratory rate and depth. The other choices are incorrect because the pneumotaxic center does not accelerate or activate breathing directly. It exerts its influence by inhibiting the inspiratory neurons in the medulla, thereby controlling the duration and frequency of inspiration. Choice D is incorrect as the pneumotaxic center does have a specific inhibitory function in the respiratory control system.

Correct Answer: A

Rationale: The correct answer is A, presence of a cough and gag reflex. After a bronchoscopy, it is crucial for the nurse to ensure the patient has a cough and gag reflex before allowing them to drink fluids to prevent aspiration. Cough reflex helps clear secretions, and gag reflex prevents fluids from entering the airway. Choices B, C, and D are incorrect as they do not directly relate to the safety of the patient's ability to swallow post-bronchoscopy.

Correct Answer: B

Rationale: The correct answer is B: Decreased diffusion capacity for oxygen. With age, respiratory dead space increases, leading to a mismatch between ventilation and perfusion in the lungs. This results in a decrease in the ability of the lungs to effectively transfer oxygen into the bloodstream, reducing the diffusion capacity for oxygen. This physiological change can lead to decreased oxygenation of tissues and organs. Summary: A: Increased diffusion of gases - Incorrect. Increased dead space does not enhance gas diffusion; instead, it impairs gas exchange. C: Decreased shunting of blood - Incorrect. Shunting refers to blood bypassing oxygenation in the lungs, which is not directly affected by dead space. D: Increased ventilation - Incorrect. While dead space may lead to increased ventilation efforts, it does not directly improve oxygen diffusion capacity.

Correct Answer: D

Rationale: The correct answer is D: Bronchioles. Bronchioles are the smallest airways in the lungs and play a crucial role in determining pulmonary resistance. They have smooth muscle surrounding them, which can contract or relax to regulate airflow and resistance. Constriction of bronchioles increases resistance, while dilation decreases it. Visceral and parietal pleura (A) are membranes that cover the lungs and chest wall, not directly involved in determining pulmonary resistance. The trachea (B) and bronchi (C) are larger airways that mainly serve as conduits for air passage and do not have as significant an impact on resistance as the bronchioles do.

Correct Answer: C

Rationale: The correct answer is C because as the SCUBA diver rises too fast, the pressure decreases rapidly. This causes the nitrogen gas that was dissolved in the blood at high pressure to form bubbles, leading to decompression sickness. Choice A is incorrect because carbon dioxide rushing into cells is not the cause of decompression sickness. Choice B is incorrect because it refers to carbon dioxide forming bubbles in the blood, which is not the mechanism of decompression sickness. Choice D is incorrect because it focuses on excess air from the SCUBA tank entering the blood, which is not the primary reason for decompression sickness.