The percent of oxygen saturation of hemoglobin when the temperature is 38 degrees centigrade is

Correct Answer: A

Rationale: The correct answer is A because at higher temperatures, oxygen dissociation from hemoglobin increases, leading to lower oxygen saturation. This is due to the Bohr effect, where increased temperature shifts the hemoglobin-oxygen dissociation curve to the right. Therefore, the percent of oxygen saturation is greater at 38 degrees Celsius compared to 43 degrees Celsius. Choice B is incorrect because higher temperatures decrease oxygen saturation. Choice C is incorrect as the saturation is not equal at different temperatures due to the Bohr effect. Choice D is incorrect because the saturation at 20 degrees Celsius would be higher than at 38 degrees Celsius.

Correct Answer: B

Rationale: The correct answer is B: Inability of the heart to pump blood effectively. Heart failure occurs when the heart is unable to pump blood efficiently to meet the body's needs. This can lead to symptoms such as shortness of breath, fatigue, and fluid retention. Explanation: 1. Heart failure is a chronic condition that develops over time due to various factors such as high blood pressure, heart attacks, or heart muscle damage. 2. The inability of the heart to pump blood effectively results in reduced blood flow to the body's organs and tissues. 3. This can lead to a buildup of fluid in the lungs and other parts of the body, causing symptoms like shortness of breath and swelling. 4. A sudden stoppage of the heart (Choice A) would result in cardiac arrest, not heart failure. 5. Accumulation of excess cholesterol in the arteries (Choice C) refers to atherosclerosis, not heart failure. 6. An irregular heartbeat (Choice D) may be a symptom

Correct Answer: B

Rationale: The correct answer is B: expiration. The internal intercostal muscles are used during expiration to decrease the size of the thoracic cavity, increasing the pressure in the lungs, causing air to be pushed out. During inspiration, the external intercostal muscles are used to expand the thoracic cavity. Choice A is incorrect as it refers to inspiration. Choice C is incorrect because internal intercostal muscles are not involved in both inspiration and expiration simultaneously. Choice D is incorrect as there is no specific muscle action associated with a "pause" in breathing.

Correct Answer: A

Rationale: The correct answer is A: hilum. Hilum refers to a slit or roughly triangular shape on the mediastinal surface of an organ where blood vessels, nerves, and lymphatics enter or exit. This anatomical feature is commonly seen in organs like the lung, kidney, and spleen. The other choices are incorrect because B: fasciae are layers of connective tissue, C: Fissures are deep grooves or clefts between structures, and D: indentation refers to a shallow recess or notch, which do not specifically describe the slit or triangular shape found at the hilum.

Correct Answer: D

Rationale: The correct answer is D: Atypical pneumonia. Patients with AIDS are most susceptible to atypical pneumonia caused by organisms like Pneumocystis jiroveci. This is due to their weakened immune system. Hypostatic pneumonia is typically seen in bedridden patients, not specific to AIDS. Streptococcus pneumoniae is a common cause of community-acquired pneumonia but not particularly associated with AIDS. Therefore, the correct choice is D, as it aligns with the specific risk profile of AIDS patients for atypical pneumonia.