Carbonic anhydrase

Correct Answer: D

Rationale: Carbonic anhydrase catalyzes the reversible reaction between carbon dioxide and water to form carbonic acid, which then dissociates into bicarbonate and hydrogen ions. It is indeed found in red blood cells, aiding in CO2 transport. Therefore, all the statements are true, making option D the correct answer.

Correct Answer: C

Rationale: The correct answer is C: 500 ml. Tidal volume refers to the amount of air inspired or expired during normal breathing. In adult humans, the average tidal volume is around 500 ml. This volume represents the typical amount of air exchanged with each breath. Choices A, B, and D are incorrect because they do not accurately reflect the standard tidal volume in human beings. Option A (1000 ml) and B (1500 ml) are too high for a normal tidal volume, while option D (4.5 ml) is too low. Therefore, the correct answer is C as it aligns with the average tidal volume in human beings.

Correct Answer: D

Rationale: The correct answer is D: Spasm in bronchial muscles. Asthma is a chronic respiratory condition characterized by inflammation and narrowing of the airways, leading to difficulty breathing. Bronchial muscles in the airways undergo spasms, causing constriction and making it hard to breathe. Infection of the trachea (A) or lungs (B) may lead to respiratory symptoms but is not the primary cause of asthma. Bleeding into the pleural cavity (C) is unrelated to the pathophysiology of asthma. Therefore, the correct answer is D as it directly correlates with the underlying mechanism of asthma.

Correct Answer: C

Rationale: The correct answer is C. Tying a square knot at the back of the neck is incorrect because it can be too tight and cause discomfort or restrict airflow. A is correct as holding the device securely is necessary for safety. B is correct as suctioning before changing ties prevents aspiration. D is correct as using half-strength peroxide is appropriate for cleaning. Tying a square knot can lead to complications, making it the action that requires intervention.

Correct Answer: B

Rationale: The correct answer is B, a 36-year-old who fractured his left femur. This client is not at risk for airway loss related to aspirated secretions because a femur fracture does not directly impact the airway or swallowing function. Traumatic brain injury (choice A), radiation therapy (choice C), and quadriplegia (choice D) can all impair the client's ability to protect their airway and increase the risk of aspirating secretions. Therefore, these clients are at higher risk compared to the client with a femur fracture.