Nursing Elites

1. When educating a client about to undergo a pacemaker insertion, the nurse explains the normal phases of cardiac muscle tissue. During the repolarization phase, the nurse will stress that membranes must be repolarized before they can be re-excited. Within the cell, the nurse understands that:

• A. Potassium channels open while sodium channels close, causing repolarization to the resting state.
• B. The influx of calcium is the primary stimulus for the repolarization of cardiac tissue.
• C. Only the electrical activity within the heart will determine when repolarization occurs.
• D. The cell membranes need to stay calm, resulting in muscle tissue becoming refractory.

Correct answer: A

Rationale: During the repolarization phase of cardiac muscle tissue, potassium channels open while sodium channels close. This process is crucial for the cardiac muscle to return to its resting state after depolarization. Potassium moving out of the cell and sodium staying out helps reset the membrane potential and prepare the cell for the next depolarization phase. The influx of calcium is not the primary stimulus for repolarization in cardiac tissue; it is mainly involved in the depolarization phase. While electrical activity within the heart influences repolarization, the specific ion movements described in choice A are what physiologically drive repolarization. Cell membranes need to be in an active state during repolarization, not calm, to facilitate the necessary ion movements for muscle tissue to properly function.

2. A 44-year-old man presents with muscle weakness and fatigue. He states that he has experienced difficulty climbing stairs and even holding his arms up to comb his hair. Which test is most likely to help confirm the diagnosis?

• A. Electromyography (EMG)
• B. Nerve conduction studies
• C. Muscle biopsy
• D. Blood test for autoantibodies

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.

3. A 65-year-old man is admitted to the intensive care unit from the operating room after a triple coronary artery bypass graft. He is intubated and on a ventilator. Lactic acid levels were normal postoperatively, but now they are rising. The increased level could be an indication of:

• A. excessive sedation
• B. bowel ischemia
• C. excessive volume infusion in the operating room
• D. mild hypothermia postoperatively

Correct answer: B

Rationale: In this scenario, the rising lactic acid levels in a 65-year-old man after a coronary artery bypass graft could indicate bowel ischemia. Bowel ischemia can lead to anaerobic metabolism, causing an increase in lactic acid levels. Excessive sedation may cause respiratory depression but would not directly lead to rising lactic acid levels. Excessive volume infusion in the operating room might cause fluid overload but would not typically result in rising lactic acid levels. Mild hypothermia postoperatively could lead to shivering and increased oxygen consumption, but it is less likely to be the primary cause of rising lactic acid levels in this context.

4. What is the pathophysiologic process responsible for the decreased glomerular filtration rate in a patient with acute glomerulonephritis?

• A. Decreased renal-induced constriction of the renal arteries
• B. Immune complex deposition, increased capillary permeability, and cellular proliferation
• C. Necrosis of 70% or more of the nephrons secondary to increased kidney interstitial hydrostatic pressure
• D. Scar tissue formation throughout the proximal convoluted tubule secondary to toxin-induced collagen synthesis

Correct answer: B

Rationale: The correct answer is B: Immune complex deposition, increased capillary permeability, and cellular proliferation. Acute glomerulonephritis is characterized by inflammation of the glomeruli in the kidneys. This inflammation leads to the deposition of immune complexes, increased capillary permeability, and cellular proliferation, which collectively contribute to a decreased glomerular filtration rate. Choice A is incorrect as decreased renal-induced constriction of the renal arteries would not directly result in decreased glomerular filtration rate. Choice C is incorrect as necrosis of nephrons due to increased kidney interstitial hydrostatic pressure would affect kidney function differently. Choice D is incorrect as scar tissue formation in the proximal convoluted tubule due to toxin-induced collagen synthesis is not a typical feature of acute glomerulonephritis.

5. A 1-year-old child will receive her scheduled MMR vaccination shortly. The nurse should teach the child's parents that she may develop what possible adverse effect related to the administration of this vaccine?

• A. Cough and fever
• B. Pallor and listlessness
• C. Serum sickness
• D. Nausea and vomiting

Correct answer: A

Rationale: The correct answer is A: Cough and fever. After receiving the MMR vaccine, some children may experience mild adverse effects such as a low-grade fever and a mild cough. These symptoms are normal reactions to the vaccine and indicate that the child's immune system is responding appropriately. Choices B, C, and D are incorrect because pallor and listlessness, serum sickness, nausea, and vomiting are not common adverse effects associated with the MMR vaccine in children.

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