Cardiovascular System Exam

Correct Answer: A

Rationale: The correct answer is A: Right atrium. The right atrium is the heart chamber that receives deoxygenated blood returning from the body via the superior and inferior vena cava. The blood enters the right atrium from the vena cava and then passes through the tricuspid valve into the right ventricle. Choices B, C, and D are incorrect because the left atrium receives oxygenated blood from the lungs, the right ventricle pumps blood to the lungs for oxygenation, and the left ventricle pumps oxygenated blood to the body.

Correct Answer: A

Rationale: The correct answer is A: Contractility. Contractility specifically refers to the change in the force of contraction of the heart muscle without changing its length. In this scenario, the focus is on the change in the inotropic state of the muscle, which directly relates to contractility. Choice B, Excitability, refers to the ability of a cell to respond to a stimulus, not specifically related to changes in contractile force. Choice C, Refractoriness, pertains to the period during which a cell is unresponsive to a new stimulus. Choice D, Automaticity, refers to the ability of cardiac cells to spontaneously generate electrical impulses.

Correct Answer: A

Rationale: Asthma is the correct answer. It is a chronic respiratory condition where the airways become inflamed and narrowed, leading to episodes of wheezing, breathlessness, chest tightness, and coughing. Asthma is characterized by reversible airflow obstruction, differentiating it from COPD, which involves irreversible airflow limitation. Bronchitis is an inflammation of the bronchial tubes without the same reversible airflow obstruction seen in asthma. Pneumonia is an infection of the lung tissue and does not involve chronic inflammation and narrowing of the airways like asthma.

Correct Answer: A

Rationale: Atherosclerosis is the correct answer. It is the buildup of plaque in the arteries, leading to the narrowing of blood vessels, reduced blood flow, and an increased risk of heart attacks, strokes, and other cardiovascular diseases. Arteriosclerosis (choice B) refers to the hardening and thickening of arterial walls, while hypertension (choice C) is high blood pressure, and diabetes (choice D) is a metabolic disorder characterized by high blood sugar levels. Therefore, choices B, C, and D are incorrect in the context of the question.

Correct Answer: A

Rationale: Automaticity is the correct answer because it refers to the inherent ability of cardiac cells to generate electrical impulses without the need for external stimulation. Contractility (Choice B) is the ability of the heart muscle to contract and generate force, not related to electrical impulse generation. Conductivity (Choice C) refers to the ability of cardiac cells to transmit electrical impulses from cell to cell, not the spontaneous generation of impulses. Refractoriness (Choice D) is the period during which the cardiac cells are recovering and not able to respond to a new stimulus, not the spontaneous generation of impulses.