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. Where are most body fluids located?

• A. Intravascular space.
• B. Intracellular space.
• C. Extracellular space.
• D. Transcellular space.

Correct answer: B

Rationale: Most body fluids are located within cells in the intracellular space. While the extracellular space also contains body fluids, the majority is found within the cells. Intravascular space refers to fluids within blood vessels, and transcellular space includes fluids in compartments like cerebrospinal, pleural, and peritoneal cavities.

3. Peritonitis is a condition that can result in serious complications. Identify one of the complications.

• A. Increased peristalsis
• B. Dizziness and malaise
• C. Sepsis and shock
• D. Nausea and vomiting

Correct answer: C

Rationale: Corrected Rationale: Peritonitis can lead to severe complications such as sepsis and shock due to the infection spreading in the abdominal cavity. Sepsis is a systemic inflammatory response to infection, and shock is a life-threatening condition where the body's organs are not receiving enough blood flow. Choices A, B, and D are incorrect. Increased peristalsis is not a typical complication of peritonitis; dizziness and malaise, as well as nausea and vomiting, are symptoms rather than complications of the condition.

4. A patient with severe peripheral vascular disease has developed signs of dry gangrene on the great toe of one foot. Which of the following pathophysiologic processes most likely contributed to this diagnosis?

• A. Inappropriate activation of apoptosis
• B. Bacterial invasion
• C. Impaired arterial blood supply
• D. Metaplastic cellular changes

Correct answer: C

Rationale: The correct answer is C: Impaired arterial blood supply. Dry gangrene is typically caused by impaired arterial blood supply, leading to tissue death without bacterial infection. Choices A, B, and D are incorrect. Inappropriate activation of apoptosis is not a common cause of dry gangrene. Bacterial invasion usually leads to wet gangrene, not dry gangrene. Metaplastic cellular changes are not directly associated with the development of dry gangrene.

5. An experiment is designed to determine specific cell types involved in cell-mediated immune response. The experimenter is interested in finding cells that attack cells that have specific antigens. Which cells should be isolated?

• A. Lymphokine-producing cells
• B. Cytotoxic T cells
• C. Helper T cells
• D. Macrophages

Correct answer: B

Rationale: Cytotoxic T cells are the key players in cell-mediated immunity as they directly attack cells displaying specific antigens. Lymphokine-producing cells (Choice A) are involved in cytokine production, while Helper T cells (Choice C) assist in activating other immune cells. Macrophages (Choice D) are phagocytic cells that engulf and digest pathogens, but they are not the primary cells responsible for directly attacking cells with specific antigens in cell-mediated immunity.

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