The partial pressure of oxygen in atmospheric air at sea level is

Correct Answer: A

Rationale: The correct answer is A because the partial pressure of oxygen decreases with increasing altitude due to the decrease in atmospheric pressure. At sea level, the atmospheric pressure is higher, resulting in a higher partial pressure of oxygen compared to the top of Mt. Everest. Choice B is incorrect because the partial pressure of oxygen is not higher at higher altitudes. Choice C is incorrect because the partial pressure of oxygen is not equal at sea level and Mt. Everest. Choice D is incorrect because the question specifically asks about the partial pressure of oxygen only, not the sum of partial pressures from other gases.

Correct Answer: D

Rationale: The correct answer is D, pseudostratified ciliated columnar epithelium. This type of epithelium lines the conducting portion of the respiratory tract because it contains cilia that help sweep mucus and debris out of the airways. It appears to be stratified but is actually a single layer of cells with varying heights, giving it a pseudostratified appearance. Simple squamous epithelium (choice A) is too thin for the respiratory tract, simple columnar epithelium (choice B) lacks cilia for mucus clearance, and stratified ciliated columnar epithelium (choice C) is not a valid type of epithelium.

Correct Answer: C

Rationale: The correct answer is C: Beta-blockers. Beta-blockers are commonly prescribed in heart failure to manage symptoms and improve outcomes by reducing the heart's workload and improving its efficiency. They help lower blood pressure, decrease heart rate, and improve heart function. Antibiotics (A) are used to treat bacterial infections, not heart failure. Antidepressants (B) are used for mental health conditions, not heart failure. Antihistamines (D) are used to treat allergies, not heart failure.

Correct Answer: A

Rationale: The correct answer is A: septal cells. Type 2 alveolar cells are also known as septal cells because they are located in the alveolar septa. These cells are responsible for producing and secreting surfactant, a substance that helps reduce surface tension in the alveoli and prevents them from collapsing. Choice B, petal cells, is incorrect because there is no such term used to describe these cells. Choice C, Surfactant, is incorrect because surfactant is the substance produced by type 2 alveolar cells, not the name of the cells themselves. Choice D, respiratory cell, is incorrect because it is a vague term that does not specifically refer to type 2 alveolar cells.

Correct Answer: C

Rationale: Rationale: - Answer C is correct because antibiotics should only be prescribed for bacterial infections, not viral ones like acute bronchitis. - Step 1: Recognize acute bronchitis is commonly caused by viruses, not bacteria. - Step 2: Understand that unnecessary antibiotic use contributes to antibiotic resistance. - Step 3: Therefore, antibiotics should only be used when a bacterial infection is confirmed through sputum culture. Summary: - Answer A is incorrect as antibiotics are not the first-line treatment for acute bronchitis. - Answer B is incorrect as it correctly states antibiotics do not treat viral conditions. - Answer D is incorrect as antibiotics do not inhibit the body's inflammatory response but target bacterial growth.