A 17-year-old male is admitted following an automobile accident. He is very anxious, dyspneic, and in severe pain. The left chest wall moves in during inspiration and balloons out when he exhales. The nurse understands these symptoms are most suggestive of?

Correct Answer: B

Rationale: The correct answer is B: Flail chest. Flail chest is characterized by paradoxical movement of a segment of the chest wall due to multiple rib fractures. In this case, the left chest wall moving in during inspiration and out during expiration indicates this paradoxical movement. This leads to ineffective breathing, causing dyspnea and anxiety. Hemothorax (A) is accumulation of blood in the pleural cavity, not associated with chest wall movement. Atelectasis (C) is collapse of lung tissue, not associated with chest wall movement. Pleural effusion (D) is accumulation of fluid in the pleural space, also not associated with paradoxical chest wall movement.

Correct Answer: D

Rationale: The correct answer is D: diffusion. Oxygen and carbon dioxide move in and out of cells through simple diffusion, which is the passive movement of molecules from an area of high concentration to an area of low concentration. This process occurs due to the concentration gradient of these gases. Osmosis (Choice C) is the movement of water across a selectively permeable membrane, not gases like oxygen and carbon dioxide. Exocytosis and endocytosis (Choice A) involve the transport of larger molecules and particles in and out of cells, not gases. Bulk flow (Choice B) involves the movement of fluids in response to pressure differences, not the specific movement of oxygen and carbon dioxide molecules. Therefore, diffusion is the correct mechanism for the movement of oxygen and carbon dioxide in the body due to their small molecular size and the concentration gradient present.

Correct Answer: D

Rationale: The correct answer is D because hypoxia, which is a condition of low oxygen levels in the body, can indeed lead to hyperventilation, as the body tries to compensate. It can also cause symptoms like headaches, nausea, and lethargy due to the lack of oxygen reaching the brain and other organs. Severe hypoxia can lead to loss of consciousness and even death if oxygen levels are not restored promptly. Therefore, all the statements in choices A, B, and C are true in relation to hypoxia, making option D the correct choice.

Correct Answer: A

Rationale: The correct answer is A because in frogs, respiration is mainly driven by buccal pumping using their mouth cavity and floor of the mouth, while in humans, diaphragm and ribs play a crucial role in expanding and contracting the chest cavity for breathing. Choices B and C are incorrect as both frogs and humans have lungs as respiratory organs and respiration occurs due to a pressure gradient in both species. Choice D is incorrect as the difference lies in the involvement of the diaphragm and ribs in respiration.

Correct Answer: B

Rationale: The correct answer is B: Hyperbolic. Myoglobin exhibits a hyperbolic oxygen dissociation curve due to its high affinity for oxygen, allowing it to bind oxygen quickly and efficiently at low partial pressures. This curve represents a simple one-to-one binding relationship between myoglobin and oxygen. The other choices are incorrect because A (Hypobolic) does not accurately describe myoglobin's binding characteristics, C (Linear) is not representative of the typical oxygen binding behavior of myoglobin, and D (Sigmoid) is more characteristic of hemoglobin, which exhibits cooperative binding of oxygen.