Which of the following are signs and symptoms of myocardial infarction?

Correct Answer: A

Rationale: The correct answer is A. Persistent chest pain that may radiate to the arm is a classic symptom of myocardial infarction. This pain is typically described as crushing, pressure-like, or squeezing. Choice B is incorrect because brief sternal chest pain on inspiration is not characteristic of myocardial infarction. Choice C is incorrect because rapid respirations with left-sided weakness and numbness are not typical symptoms of myocardial infarction. Choice D is incorrect because left upper quadrant abdominal pain that radiates to the back and shoulder is not a common presentation of myocardial infarction.

Correct Answer: B

Rationale: The correct answer is B: Obstruction of the coronary arteries. Angina is primarily caused by a reduced blood flow to the heart due to blockages or narrowing in the coronary arteries. Choice A is incorrect because while increased oxygen demand can contribute to angina symptoms, it is not the primary cause. Choice C is incorrect as angina is not caused by a lack of oxygen in the lungs. Choice D is also incorrect as angina is not related to decreased blood supply to the liver.

Correct Answer: B

Rationale: The correct answer is B: Autoimmune destruction of the thyroid gland. In hypothyroidism, the thyroid gland does not produce enough hormones to meet the body's needs. This can be due to autoimmune destruction of the thyroid gland, where the body's immune system mistakenly attacks the thyroid tissue. Choices A, C, and D are incorrect. Overproduction of cortisol is associated with conditions like Cushing's syndrome, overactivity of the thyroid gland is a characteristic of hyperthyroidism, and insufficient iodine intake can lead to goiter but not necessarily hypothyroidism.

Correct Answer: A

Rationale: The correct answer is A: Erythropoietin. The kidneys produce erythropoietin to stimulate the production of red blood cells. Insulin and glycogen are not hormones secreted by the kidneys; insulin is produced by the pancreas, and glycogen is a stored form of glucose. Testosterone is a hormone primarily produced by the testes in males and to a lesser extent in females. Thyroid stimulating hormone is produced by the pituitary gland to regulate thyroid function, not red blood cell production.

Correct Answer: B

Rationale: A pulmonary embolism is commonly caused by a blood clot that originates in the venous system of the lower extremity and travels to the lungs, blocking blood flow. This clot is known as a venous thromboembolism. An autoimmune disorder (Choice A) is not typically associated with pulmonary embolism. Intracranial pressure (Choice C) refers to pressure inside the skull and is unrelated to pulmonary embolism. Hypotension (Choice D) is low blood pressure and is not a common cause of pulmonary embolism.