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. Which of the following statements describes an active cellular membrane exchange process?

• A. Sodium moving out of cells and potassium moving into cells
• B. The movement of water from an area of low solute concentration to an area of high solute concentration
• C. The movement of insulin using a protein to travel across the cell membrane
• D. Oxygen moving across the pulmonary capillaries to an area of high carbon dioxide

Correct answer: A

Rationale: The correct answer is A. In active transport, energy is expended to move substances against their concentration gradient. Sodium moving out of cells and potassium moving into cells is an example of active transport because it requires energy to pump these ions across the cell membrane against their concentration gradients. Choices B, C, and D describe passive processes where substances move along their concentration gradients without the input of energy.

3. Cellular swelling is:

• A. Irreversible
• B. Evident early in all types of cellular injury
• C. Manifested by decreased intracellular sodium
• D. None of the above is correct

Correct answer: B

Rationale: Cellular swelling is indeed evident early in all types of cellular injury. This occurs due to the influx of water into the cell, leading to swelling. Choice A is incorrect because cellular swelling is reversible if the injury is not severe. Choice C is incorrect because cellular swelling is not manifested by decreased intracellular sodium; in fact, it is associated with increased intracellular sodium due to water influx. Choice D is incorrect as option B is the correct statement.

4. What aspect of hormonal contraceptives places a woman at the greatest risk for the development of blood clots?

• A. Hormonal contraceptives increase serum triglyceride and cholesterol levels.
• B. Hormonal contraceptives increase platelet levels.
• C. Hormonal contraceptives increase blood levels of clotting factors.
• D. Hormonal contraceptives cause injury to blood vessel linings.

Correct answer: C

Rationale: The correct answer is C. Hormonal contraceptives increase blood levels of clotting factors, particularly factors II, VII, IX, and X. This elevation in clotting factors can predispose individuals to thromboembolic events, including blood clots. Choices A, B, and D are incorrect because hormonal contraceptives do not have a significant effect on serum triglycerides and cholesterol, platelet levels, or causing direct injury to blood vessel linings as the primary mechanism for clot formation.

5. The early stages of atheroma development are characterized by:

• A. macrophages full of oxidized low-density lipoprotein (LDL; i.e., foam cells) in the intima
• B. accumulation of lipids in the intima (i.e., fatty streak)
• C. accumulation of proteins such as collagen and elastin (i.e., fibrous cap)
• D. development of calcium and a necrotic lipid core

Correct answer: A

Rationale: The correct answer is A. In the early stages of atheroma development, macrophages accumulate oxidized low-density lipoprotein (LDL) and transform into foam cells, leading to the formation of fatty streaks in the intima of blood vessels. This process is a hallmark of the initial stages of atherosclerosis. Choice B is incorrect as it describes the accumulation of lipids in the intima, which is a later event following foam cell formation. Choice C is also incorrect as it refers to the accumulation of proteins forming the fibrous cap, which occurs at a later stage to stabilize the atheroma. Choice D is incorrect as it describes the development of calcium and a necrotic lipid core, typically seen in advanced atherosclerosis rather than the early stages.

Similar Questions