Nursing Elites

1. Which part of the heart is responsible for generating the QRS complex on an ECG?

• A. Sinoatrial node (SA node)
• B. Atrioventricular node (AV node)
• C. Bundle of His
• D. Ventricular muscle cells

Correct answer: D

Rationale: The QRS complex on an ECG represents ventricular depolarization. This electrical activity is generated by the ventricular muscle cells. While the SA node generates the P wave, the AV node delays the impulse, and the Bundle of His and Purkinje fibers assist in rapidly conducting the impulse through the ventricles, it is the ventricular muscle cells that specifically create the QRS complex. Therefore, choice D, Ventricular muscle cells, is the correct answer. Choices A, B, and C are incorrect as they are primarily involved in initiating and coordinating the electrical impulses in the heart but do not directly generate the QRS complex on an ECG.

2. Which of the following structures is responsible for transmitting electrical impulses in the nervous system?

• A. Neuron
• B. Axon
• C. Myelin
• D. Dendrite

Correct answer: A

Rationale: The correct answer is A: Neuron. Neurons are specialized cells that transmit electrical impulses in the nervous system. While the axon is the part responsible for conducting these impulses over long distances, it is the neuron as a whole that is ultimately responsible for transmitting electrical impulses. Myelin is a fatty substance that surrounds and insulates axons, speeding up signal transmission. Dendrites, on the other hand, receive signals from other neurons. Therefore, although the axon plays a significant role in transmission, the neuron is the fundamental unit responsible for transmitting electrical impulses in the nervous system.

3. What is the function of arrector pili muscles?

• A. To control sweat production
• B. To contract and cause goosebumps
• C. To produce sebum
• D. To sense touch

Correct answer: B

Rationale: The correct function of arrector pili muscles is to contract and cause goosebumps. These small muscles are attached to hair follicles in mammals. When they contract, they cause the hair to stand on end, resulting in goosebumps. This physiological response is often triggered by cold temperatures or emotional states like fear, helping mammals conserve heat or appear larger in threatening situations. Choices A, C, and D are incorrect. Arrector pili muscles are not involved in controlling sweat production (Choice A), producing sebum (Choice C), or sensing touch (Choice D).

4. Which of the following serves as a standard or series of standards for comparing the results of an experiment?

• A. A control
• B. A variable
• C. A constant
• D. Collected data

Correct answer: A

Rationale: A control is a standard used to compare the outcomes of an experiment and is crucial for determining the effect of the variables being tested. It helps isolate and measure the impact of the independent variable by providing a baseline for comparison. While variables may change, constants remain consistent, and collected data is the information obtained from the experiment. A control specifically serves as the standard for comparison in an experiment, making it the correct choice. Variables, although important, are what are being altered and tested in an experiment, constants are factors that are kept consistent throughout the experiment, and collected data is the information gathered from the experiment, none of which specifically serve as the standard for comparison.

5. What is the difference between a germline mutation and a somatic mutation?

• A. Germline mutations are passed to offspring, while somatic mutations are not.
• B. Germline mutations occur in reproductive cells, while somatic mutations occur in body cells.
• C. Germline mutations only affect genes, while somatic mutations can affect any DNA.
• D. Germline mutations are always beneficial, while somatic mutations are always harmful.

Correct answer: B

Rationale: Rationale: - Germline mutations are changes in the DNA of reproductive cells (sperm or egg cells) and can be passed on to offspring, affecting all cells in the resulting organism. - Somatic mutations are changes in the DNA of non-reproductive cells (body cells) and are not passed on to offspring. These mutations only affect the cells that arise from the mutated cell. - Option A is incorrect because somatic mutations are not passed to offspring. - Option C is incorrect because both germline and somatic mutations can affect any DNA. - Option D is incorrect because the effects of mutations, whether germline or somatic, can be beneficial, harmful, or have no significant impact.

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