Residual volume of the lung is

Correct Answer: A

Rationale: The correct answer is A: 1200 ml. Residual volume is the amount of air left in the lungs after maximum expiration. It is around 1200 ml because it cannot be exhaled due to lung elasticity. Choice B (1500 ml) is incorrect as it is higher than the normal range. Choice C (4500 ml) is incorrect as it is too high for residual volume. Choice D (500 ml) is incorrect as it is too low for residual volume.

Correct Answer: B

Rationale: Cloacal respiration is found in turtles and tortoises. These reptiles can absorb oxygen through their cloaca, a multi-functional opening used for excretion and reproduction. Turtles and tortoises lack specialized respiratory organs like lungs, and thus utilize cloacal respiration as an additional means of obtaining oxygen. Snakes (Option A) primarily rely on lung respiration. Crocodiles (Option C) have well-developed lungs for breathing. Frogs (Option D) respire through their skin and lungs but do not utilize cloacal respiration like turtles and tortoises. Therefore, the correct answer is B, as it is the only species listed that exhibits cloacal respiration.

Correct Answer: A

Rationale: The correct answer is A: Emphysema. Emphysema leads to an increase in lung compliance due to the destruction of alveolar walls, resulting in decreased elastic recoil. This decreased recoil makes it easier for the lungs to expand and increases overall lung compliance. Incorrect choices: B: Pulmonary fibrosis - Pulmonary fibrosis causes lung tissue scarring and stiffening, resulting in decreased lung compliance. C: Pleural effusion - Pleural effusion is an accumulation of fluid in the pleural space, which can restrict lung expansion and decrease lung compliance. D: Acute respiratory distress syndrome (ARDS) - ARDS causes inflammation and fluid buildup in the lungs, leading to decreased lung compliance due to increased stiffness and reduced ability to expand.

Correct Answer: C

Rationale: The correct answer is C: "Do you currently smoke, or have you ever smoked?" Smoking is the most significant risk factor for respiratory diseases, including lung cancer, chronic obstructive pulmonary disease, and emphysema. Asking about smoking history is crucial in assessing lung disease risk. Rationale: 1. Smoking is the leading cause of preventable death worldwide. 2. Smoking damages the lungs and increases the risk of developing various respiratory conditions. 3. Current and past smoking status helps determine the level of risk for lung disease. 4. Tobacco smoke contains harmful chemicals that can lead to lung damage over time. Summary: A: Occupational exposure is a risk factor, but smoking has a stronger association with respiratory diseases. B: Family history is relevant but not as directly linked to individual behavior and risk as smoking. D: Air pollution can contribute to lung issues, but personal smoking history has a more direct impact on lung health.

Correct Answer: B

Rationale: The correct answer is B: intrapleural pressure. Intrapleural pressure remains negative throughout the respiratory cycle due to the opposing forces of the elastic recoil of the lungs and the chest wall. This negative pressure keeps the lungs inflated and facilitates breathing. In contrast, intrapulmonary (A) and intra-alveolar (C) pressures fluctuate during inhalation and exhalation, becoming positive and negative, respectively. Atmospheric pressure (D) remains relatively constant and serves as the reference point for pressure changes in the respiratory system.