What is an acute respiratory infection that inflames the alveoli in one or both lungs, causing them to fill with fluid or pus?

Correct Answer: A

Rationale: The correct answer is A: Pneumonia. Pneumonia is an acute respiratory infection that specifically inflames the alveoli in the lungs, leading to fluid or pus accumulation. This condition can affect one or both lungs. Bronchitis (B) is inflammation of the bronchial tubes, not the alveoli. Tuberculosis (C) is a bacterial infection that primarily affects the lungs but does not always involve alveoli inflammation. Asthma (D) is a chronic respiratory condition characterized by airway inflammation and constriction, not alveoli inflammation like in pneumonia.

Correct Answer: A

Rationale: The PR interval measures the time it takes for the electrical signal to travel from the atria to the ventricles, reflecting atrial depolarization and the delay at the AV node before ventricular activation. Option A is correct as it accurately describes the PR interval. Option B is incorrect as the PR interval does not measure ventricular depolarization. Option C is incorrect as the PR interval does not represent ventricular repolarization. Option D is incorrect as it describes the QT interval, not the PR interval.

Correct Answer: A

Rationale: The correct answer is A: Arrhythmia. Arrhythmia refers to an irregular heartbeat caused by malfunctioning of the heart's electrical system. Bradycardia (B) is a slow heart rate, Tachycardia (C) is a fast heart rate, and Ventricular fibrillation (D) is a life-threatening arrhythmia characterized by rapid, irregular heartbeats. Arrhythmia encompasses various types of irregular heart rhythms, making it the most appropriate choice in this context.

Correct Answer: A

Rationale: Myocarditis is the correct answer because it specifically refers to inflammation of the heart muscle often caused by a viral infection, leading to impaired heart function. It directly addresses the condition described in the question. Endocarditis is inflammation of the inner lining of the heart chambers and valves, not the heart muscle. Pericarditis is inflammation of the outer lining of the heart, not the heart muscle. Cardiomyopathy is a general term for diseases of the heart muscle that impair its ability to pump blood, but it does not specifically mention inflammation caused by viral infections.

Correct Answer: A

Rationale: The correct answer is A: Echocardiogram. An echocardiogram uses high-frequency sound waves to create detailed images of the heart's structure and function in real-time. It is a non-invasive and safe diagnostic tool commonly used to assess heart health. MRI (B) uses magnetic fields and radio waves, CT scan (C) uses X-rays, and X-ray (D) uses electromagnetic radiation, but they do not provide the same level of detail and real-time assessment of the heart as an echocardiogram does.