ATI Pathophysiology Exam 3

Correct Answer: A

Rationale: Thrombocytopenia is characterized by a decreased platelet cell count, leading to an increased risk of bleeding. Therefore, the correct answer is A. Choice B, a decreased white blood cell count, is not typically associated with thrombocytopenia. Choice C, an increased red blood cell count, is not a characteristic finding in thrombocytopenia. Choice D, an increased platelet cell count, is the opposite of what is observed in thrombocytopenia.

Correct Answer: D

Rationale: The sinoatrial node (SA node) in the atrium is indeed responsible for initiating the electrical impulse that starts the heart's rhythm. The SA node is known as the heart's natural pacemaker. Choices A, B, and C are incorrect because while the Purkinje fibers, bundle branches, and atrioventricular node play crucial roles in the conduction of the electrical impulse throughout the heart, the SA node is specifically responsible for initiating this impulse.

Correct Answer: A

Rationale: The correct answer is A: Decreased plasma proteins. Edema can be caused by decreased plasma proteins, which reduce the osmotic pressure that keeps fluid in the blood vessels. Hypotension (choice B) is low blood pressure and is not a direct cause of edema. Dehydration (choice C) involves a lack of body fluid, but it is not a direct cause of edema. Polyuria (choice D) is excessive urination and not a direct cause of edema.

Correct Answer: C

Rationale: The correct answer is C. Influenza immunization works by introducing a weakened or inactivated form of the virus into the body, allowing the immune system to recognize it as foreign. This recognition triggers the production of antibodies specific to the virus. Choice A is incorrect as the virus in the vaccine does not remain in the body until the end of the season. Choice B is incorrect as an attenuated virus does not cause immune system suppression but rather stimulates an immune response. Choice D is incorrect because the vaccine does not stay at the injection site but rather prompts a systemic immune response throughout the body.

Correct Answer: A

Rationale: The correct answer is Parathyroid hormone (Choice A). Parathyroid hormone plays a key role in regulating calcium levels in the blood. When there is an imbalance in parathyroid hormone secretion, it can lead to increased calcium levels in the blood. Antidiuretic hormone (Choice B) is involved in regulating water balance, not calcium levels. Calcitonin (Choice C) helps lower blood calcium levels and is unlikely to cause an increase. Melatonin (Choice D) regulates sleep-wake cycles and does not have a direct effect on calcium levels in the blood.