What is a condition where the pulmonary arteries become blocked by a blood clot, leading to chest pain, shortness of breath, and other symptoms?

Correct Answer: A

Rationale: The correct answer is A: Pulmonary embolism. Pulmonary embolism occurs when a blood clot blocks one of the pulmonary arteries, leading to symptoms like chest pain and shortness of breath. This condition is a medical emergency as it can be life-threatening if not treated promptly. B: Pneumothorax is the collapse of the lung due to air leaking into the chest cavity, not caused by a blood clot in the pulmonary arteries. C: Pulmonary edema is the accumulation of fluid in the lungs, causing breathing difficulties, but it is not due to a blood clot in the pulmonary arteries. D: Pulmonary hypertension is high blood pressure in the arteries of the lungs, not caused by a blockage from a blood clot.

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 correct answer is A: Cor pulmonale. Cor pulmonale is right-sided heart failure due to increased pressure in the pulmonary arteries, typically caused by chronic lung disease. This leads to the right side of the heart working harder to pump blood through the lungs, resulting in eventual failure. Pulmonary embolism (C) is a sudden blockage in the pulmonary artery, not a chronic condition. Heart failure (B) is a general term for when the heart is unable to pump blood effectively, not specific to the right side. Myocarditis (D) is inflammation of the heart muscle, not directly related to pulmonary hypertension.

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.