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: The correct answer is 'Bronchitis.' Bronchitis refers to the inflammation of the bronchial tubes, which can be acute or chronic, leading to symptoms like coughing and increased mucus production. Choice B, 'Asthma,' is a chronic condition characterized by inflammation and narrowing of the airways, often causing wheezing and shortness of breath. Choice C, 'Pneumonia,' is an infection that inflames air sacs in one or both lungs, leading to symptoms like fever, cough, and difficulty breathing. Choice D, 'Cystic fibrosis,' is a genetic disorder that affects the lungs and digestive system, causing mucus buildup and respiratory issues.

Correct Answer: A

Rationale: Pneumothorax is the correct answer for this question. Pneumothorax is the collapse of a lung caused by the presence of air in the pleural space between the lung and chest wall. This condition can lead to chest pain, shortness of breath, and may require emergency treatment such as chest tube insertion to remove the air. Pleural effusion is the accumulation of fluid in the pleural space, not air. Atelectasis is the collapse or closure of a lung resulting in reduced or absent gas exchange. Pulmonary fibrosis is a condition characterized by scarring and thickening of lung tissue, not related to air leaking into the pleural space.

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: Foods high in potassium. Spironolactone is a potassium-sparing diuretic, meaning it helps the body retain potassium and excrete sodium. Consuming foods high in potassium while on spironolactone can lead to an excess of potassium in the body, potentially causing hyperkalemia. Choices B, C, and D are incorrect because spironolactone does not directly interact with sodium, calcium, or chloride in a way that would require specific dietary restrictions related to these minerals.