When reviewing the purpose/action of neurotransmitters as they interact with different receptors, the nursing instructor gives an example using acetylcholine. When acetylcholine is released at the sinoatrial node in the right atrium of the heart, it is:

Correct Answer: B

Rationale: Acetylcholine acts as an inhibitory neurotransmitter at the sinoatrial node. It slows down the heart rate by decreasing the firing rate of the sinoatrial node, which serves as the heart's natural pacemaker. Neurotransmitters do not have a charge, so choice A is incorrect. Choice C is wrong as overstimulation is not a characteristic of acetylcholine at the sinoatrial node. Choice D is also incorrect because acetylcholine actively influences heart rate regulation when released at the sinoatrial node.

Correct Answer: A

Rationale: The correct answer is Electromyography (EMG). EMG is commonly used to diagnose conditions involving muscle weakness and fatigue, such as myasthenia gravis. Nerve conduction studies primarily assess nerve function rather than muscle involvement. While a muscle biopsy can provide valuable information, EMG is more specific for evaluating muscle function in this context. A blood test for autoantibodies may be helpful in certain autoimmune conditions but is not the primary test for confirming the diagnosis based on the patient's symptoms of muscle weakness and fatigue.

Correct Answer: C

Rationale: Ptosis (drooping eyelid) and diplopia (double vision) are classic symptoms of myasthenia gravis. Muscle atrophy (Choice A) is not a typical early manifestation of myasthenia gravis. While facial weakness (Choice B) can occur, it is not as specific as ptosis and diplopia. Increased muscle tone (Choice D) is more indicative of conditions like spasticity, not myasthenia gravis.

Correct Answer: B

Rationale: In a client presenting with chest pain, shortness of breath, and ST-segment elevation on ECG, the priority nursing intervention is to prepare the client for emergent coronary angiography. This procedure is crucial in diagnosing and treating acute myocardial infarction promptly. Administering aspirin (Choice A) is important but not the priority over emergent coronary angiography. Administering oxygen therapy (Choice C) is supportive but does not address the underlying cause of the ST-segment elevation. Initiating CPR (Choice D) is not the priority in this scenario as the client is stable and conscious.

Correct Answer: B

Rationale: Erythrocytes with an abnormally low concentration of hemoglobin are called hypochromic. Hyperchromic refers to erythrocytes with an abnormally high concentration of hemoglobin. Macrocytic indicates larger than normal red blood cells, while microcytic refers to smaller than normal red blood cells. Therefore, in this scenario, the correct term is hypochromic.