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 mediates humoral immunity?

• A. Natural killer cells
• B. T cells
• C. B cells
• D. Neutrophils

Correct answer: C

Rationale: Humoral immunity is mediated by B cells, not natural killer cells, T cells, or neutrophils. B cells are responsible for producing antibodies, which are essential components of humoral immunity.

3. A person is given an attenuated antigen as a vaccine. When the person asks what was given in the vaccine, how should the nurse respond? The antigen is:

• A. Alive, but less infectious
• B. Mutated, but highly infectious
• C. Normal, but not infectious
• D. Inactive, but infectious

Correct answer: A

Rationale: An attenuated antigen used in a vaccine is alive but less infectious, aiming to stimulate an immune response. Choice B is incorrect because an attenuated antigen is not highly infectious. Choice C is incorrect as the antigen is intentionally altered to be less infectious. Choice D is incorrect as an attenuated antigen is not infectious.

4. A toddler is displaying signs/symptoms of weakness and muscle atrophy. The pediatric neurologist suspects it may be a lower motor neuron disease called spinal muscular atrophy (SMA). The client's family asks how he got this. The nurse will respond:

• A. This could result from playing in soil and then ingesting bacteria that is now attacking his motor neurons.
• B. No one really knows how this disease is formed. We just know that in time, he may grow out of it.
• C. This is a degenerative disorder that tends to be inherited as an autosomal recessive trait.
• D. This is a segmental demyelination disorder that affects all nerve roots and eventually all muscle groups as well.

Correct answer: C

Rationale: The correct answer is C. Spinal muscular atrophy (SMA) is an inherited disorder, often autosomal recessive, that affects lower motor neurons. Choice A is incorrect because SMA is not caused by ingesting bacteria from playing in soil. Choice B is incorrect as SMA is not something that a person grows out of. Choice D is incorrect because SMA is not a demyelination disorder that affects nerve roots and muscle groups.

5. A 21-year-old male is brought to the ED following a night of partying in his fraternity. His friends found him 'asleep' and couldn't get him to respond. They cannot recall how many alcoholic beverages he drank the night before. While educating a student nurse and the man's friends, the nurse begins by explaining that alcohol is:

• A. A water-soluble compound that is easily absorbed by the gastric lining of the stomach.
• B. Very lipid-soluble and rapidly crosses the blood–brain barrier.
• C. Able to reverse the transport of some substances to remove them from the brain.
• D. Very likely to cause sedation and therefore the client just needs to sleep it off.

Correct answer: B

Rationale: The correct answer is B. Alcohol is very lipid-soluble and rapidly crosses the blood–brain barrier, leading to its effects on the central nervous system and causing symptoms like sedation and unconsciousness. Choice A is incorrect because alcohol is not water-soluble; it is lipid-soluble. Choice C is incorrect as alcohol does not reverse the transport of substances from the brain. Choice D is incorrect as sedation from alcohol is not a reason to just 'sleep it off' in cases of alcohol poisoning, which can be life-threatening and requires medical attention.

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