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 patient is prescribed sildenafil (Viagra) for erectile dysfunction. What is a key contraindication that the nurse should review with the patient?

• A. History of hypertension
• B. Use of nitrates
• C. Use of antihypertensive medications
• D. History of peptic ulcer disease

Correct answer: B

Rationale: The correct answer is B: 'Use of nitrates.' Sildenafil (Viagra) is contraindicated in patients taking nitrates due to the risk of severe hypotension. Nitrates and sildenafil both act as vasodilators, and their combined use can lead to a dangerous drop in blood pressure. Choices A, C, and D are incorrect because having a history of hypertension, using antihypertensive medications, or having a history of peptic ulcer disease are not key contraindications for sildenafil use.

3. What is responsible for initiating clonal selection?

• A. B cells
• B. T cells
• C. Antigens
• D. Lymphocytes

Correct answer: C

Rationale: Antigens are the correct answer as they are the molecules that trigger the immune response by binding to specific B or T cells. This binding activates these cells, leading to their proliferation and differentiation to fight off the antigen. B cells and T cells are the responders to antigens, not the initiators of clonal selection. Lymphocytes is a broad term encompassing both B and T cells, so it is not the specific factor responsible for initiating clonal selection.

4. Why is testosterone therapy prescribed for a 70-year-old man being treated for osteoporosis?

• A. To increase bone density
• B. To reduce the risk of fractures
• C. To enhance sexual performance
• D. To restore testosterone levels

Correct answer: D

Rationale: The primary reason for prescribing testosterone therapy for osteoporosis in men is to restore testosterone levels, not specifically to increase bone density. Testosterone plays a crucial role in maintaining bone density, so by restoring testosterone levels, it indirectly helps in maintaining bone density. Choices A and B are partially correct but do not address the primary reason for testosterone therapy in this context. Choice C is incorrect as the main focus of testosterone therapy in osteoporosis treatment is not related to enhancing sexual performance.

5. A patient is found to have liver disease, resulting in the removal of a lobe of his liver. Adaptation to the reduced size of the liver leads to ___________ of the remaining liver cells.

• A. Metaplasia
• B. Organ atrophy
• C. Compensatory hyperplasia
• D. Physiologic hyperplasia

Correct answer: C

Rationale: Compensatory hyperplasia is the process by which the remaining cells increase in number to adapt to the reduced size of the liver. In this case, after the removal of a lobe of the liver, the remaining cells undergo compensatory hyperplasia to compensate for the lost tissue. Metaplasia refers to the reversible change of one cell type to another, not an increase in cell number. Organ atrophy is the decrease in organ size due to cell shrinkage or loss, which is opposite to an increase in cell number seen in compensatory hyperplasia. Physiologic hyperplasia is the increase in cell number in response to a normal physiological demand, not specifically due to the removal of a portion of the organ.

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