Actual exchange of gases in the lungs occurs in the

Correct Answer: B

Rationale: The correct answer is B: alveoli. Alveoli are tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide takes place through diffusion. This process is crucial for oxygenating the blood and removing carbon dioxide. Bronchi (A), bronchioles (C), and trachea (D) are all parts of the respiratory system, but they do not participate directly in gas exchange. Bronchi are the main airways that branch off from the trachea, bronchioles are smaller airways that lead to the alveoli, and the trachea is the main airway that carries air to and from the lungs.

Correct Answer: B

Rationale: The correct answer is B: carbon dioxide in the blood. In the body, carbon dioxide levels are monitored by chemoreceptors in the brainstem. When carbon dioxide levels rise, it triggers an increase in breathing rate to expel excess carbon dioxide and restore the balance of gases in the blood. This process is known as the respiratory drive. Carbon monoxide (A) is a toxic gas that interferes with oxygen transport but does not directly affect breathing stimulus. Oxygen (C) levels in the blood are important for maintaining tissue oxygenation but do not directly regulate breathing. Carbonic acid (D) is a product of carbon dioxide and water, and its levels do not directly stimulate breathing.

Correct Answer: D

Rationale: The correct answer is D (1500 ml) because residual volume refers to the amount of air left in the lungs after maximal exhalation, which is around 1200-1500 ml in an average human. This volume is necessary to keep the alveoli inflated and prevent lung collapse. Choices A (500 ml), B (3-4.5 ml), and C (1000 ml) are incorrect because they do not accurately represent the typical residual volume in the lungs of an average human. Choice A is too low, choices B and C are significantly below the actual range of residual volume.

Correct Answer: C

Rationale: The diaphragm in mammals is a muscular structure that separates the thoracic and abdominal cavities. This is essential for breathing as it contracts and relaxes to facilitate the movement of air into and out of the lungs. Therefore, the correct answer is C. Choice A is incorrect because the membrane between the external and middle ear is called the eardrum or tympanic membrane. Choice B is incorrect as the membrane around the brain is the meninges. Choice D is incorrect as the membrane around the lungs is the pleura.

Correct Answer: A

Rationale: The correct answer is A because applying suction while inserting the catheter can cause damage to the tracheal mucosa and lead to bleeding or injury. The correct technique is to insert the catheter without applying suction, then apply suction while withdrawing it. Preoxygenating the client (B) is a recommended practice to prevent hypoxia. Suctioning for a total of three times if needed (C) and suctioning for only 10 to 15 seconds each time (D) are both appropriate and safe suctioning practices.