What is the relationship between the pressures at label '8'?

Correct Answer: C

Rationale: The correct answer is C: P outside < P inside. This is because pressure decreases as altitude increases. At label '8', the pressure outside the object (presumably at a higher altitude) is lower than the pressure inside the object. This is due to the decrease in air pressure with increasing altitude. Choice A is incorrect because at higher altitudes, the pressure outside is lower than inside. Choice B is incorrect as it suggests the opposite relationship. Choice D is incorrect as it does not accurately describe the relationship between the pressures at label '8'.

Correct Answer: B

Rationale: The correct answer is B: a drop in tidal volume. Severing sensory fibers from the lungs would lead to decreased feedback to the brain, resulting in less inhibition of the inspiratory center and potentially overinflation of the lungs (choice C). The Hering-Breuer reflexes, responsible for preventing lung over-inflation, would disappear (choice D). However, tidal volume is primarily controlled by the respiratory muscles and respiratory center in the brain, not solely by sensory input from the lungs. Hence, severing sensory fibers would not directly lead to a drop in tidal volume.

Correct Answer: A

Rationale: The correct answer is A: pulmonary. The pulmonary circulation involves the flow of blood between the heart and the lungs. In this circulation, deoxygenated blood from the body is pumped to the lungs to pick up oxygen and release carbon dioxide. The oxygenated blood is then returned to the heart to be pumped to the rest of the body. The other choices (B: interlobular, C: respiratory, D: bronchial) are incorrect because they do not specifically refer to the circulation responsible for oxygenating blood and removing carbon dioxide in the lungs. Instead, they relate to other structures or functions within the respiratory system.

Correct Answer: B

Rationale: Emphysema is the correct answer because it is a chronic respiratory disorder specifically caused by smoking. Smoking damages the air sacs in the lungs, leading to shortness of breath and difficulty breathing. Asthma is a separate condition involving airway inflammation. Respiratory alkalosis and acidosis refer to imbalances in blood pH levels, not directly caused by smoking.

Correct Answer: A

Rationale: The correct answer is A: 80 m2. The alveoli are tiny air sacs in the lungs where gas exchange occurs. The surface area of the alveoli is crucial for efficient gas exchange. The average adult human has around 300 million alveoli with a total surface area of about 70-100 m2, making option A the most accurate. Option B, C, and D are incorrect as they do not fall within the typical range of alveolar surface area. It is important to remember the importance of the large surface area of the alveoli in facilitating the exchange of oxygen and carbon dioxide during respiration.