Partial pressure of carbon dioxide in the inspired and expired air respectively

Correct Answer: A

Rationale: The partial pressure of carbon dioxide in inspired air is around 0.3 mm Hg as it is very low in atmospheric air. During expiration, the partial pressure of carbon dioxide increases to around 40 mm Hg due to its exchange in the lungs. This makes option A the correct answer. Option B is incorrect because the partial pressure of CO2 in expired air is not 32 mm Hg. Option C is incorrect as 40 mm Hg is the partial pressure in expired air, not inspired air. Option D is incorrect because 0.3 mm Hg is the partial pressure in inspired air, not expired air.

Correct Answer: B

Rationale: The correct answer is B: Increasing O2 concentration. When O2 concentration increases, it promotes the binding of oxygen to hemoglobin in the blood through the process of oxygenation. This results in the formation of oxyhemoglobin, which enhances oxygen transport in the blood. Summary: - A: Decreasing O2 concentration would hinder the binding of oxygen to hemoglobin, reducing oxygen transport efficiency. - C: Increasing CO2 concentration would lead to the formation of carbaminohemoglobin, not oxyhemoglobin. - D: Decreasing CO2 concentration would not directly promote the binding of oxygen to hemoglobin.

Correct Answer: A

Rationale: The correct answer is A because a pulmonary function test (PFT) measures lung function by assessing how much air moves in and out of the lungs when breathing. This test helps diagnose conditions like emphysema by evaluating lung capacity and air flow. Choice B is incorrect because PFTs do not measure energy obtained from oxygen, but rather focus on lung function. Choice C is incorrect as PFTs do not specifically measure lung elasticity. Choice D is incorrect because PFTs primarily assess air movement in the lungs, not the exchange of oxygen and carbon dioxide between the lungs and blood.

Correct Answer: C

Rationale: Rationale: C is correct because the spleen is a secondary lymphoid organ, not a primary one. The spleen filters blood, not lymph fluid. A is correct as the spleen is located in the described position. B is correct as the splenic vessels do communicate with the spleen at the hilum. D is correct as lymphocytes and dendritic cells are indeed concentrated in the white pulp. Summary: A, B, and D are correct statements about the spleen. C is incorrect because the spleen is a secondary lymphoid organ, not a primary one.

Correct Answer: C

Rationale: Henry's law states that the volume of gas dissolved in a solvent is directly proportional to the partial pressure of the gas above the solvent. This means that as the gas pressure increases, more gas will dissolve in the solvent. Choice C correctly describes this relationship between gas pressure and gas solubility in a solvent. Choices A and B are not related to Henry's law. Choice D is incomplete and does not provide any relevant information about Henry's law.