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Which sound waves have a lower pitch?
- A. Those waves that are closer together
- B. Those waves that are farther apart
- C. Those waves that travel a long distance
- D. Those waves that travel a short distance
Correct Answer: B
Rationale: Sound waves that are farther apart have a lower pitch. The Doppler Effect explains that as objects emitting sound move away, the sound waves become more spaced out, resulting in a lower frequency and a lower pitch. Choice A is incorrect because waves that are closer together have a higher frequency and a higher pitch. Choices C and D are not directly related to determining the pitch of sound waves.
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What are the three steps of the 'wave of excitation'?
- A. The discharge from the SA node, the peak ECG, and the excitement of the ventricle.
- B. The excitement of the ventricle, the relaxing of the ventricle, and the systemic neural response.
- C. The contraction of the atrium, the relaxation of the atrium, and the contraction of the ventricle.
- D. The excitation of the atrium, the excitement of the ventricle, and the relaxing of the ventricle.
Correct Answer: D
Rationale: The correct steps of the 'wave of excitation' are the excitation of the atrium, excitement of the ventricle, and relaxation of the ventricle. In the described process, the 'wave of excitation' starts with the discharge from the SA node, leading to the excitation of the atrium. Next, the peak ECG corresponds to the excitement of the ventricle, not its relaxation. Finally, the wave concludes with the relaxation of the ventricle, not its contraction. Therefore, choices A, B, and C are incorrect as they do not accurately describe the sequential steps of the 'wave of excitation' as presented in the extract.
What is the best summary of the passage?
- A. Electric currents within the body are due to electrostatic charges set off by the heart. Medical staff are trained to recognize any abnormalities within the heart.
- B. Every individual has unique electric currents on the surface of the body. The ECG measures and records these electric currents.
- C. The ECG systematically and rather quickly measures the stages at which the 'wave of excitation' occurs within the heart and records them. This wave has three distinct steps that spread from the SA node to the AV node.
- D. The ECG measures the electric currents within the body. These currents are detected on the surface of the body when the body is connected to an amplifier.
Correct Answer: C
Rationale: The correct summary of the passage is option C. The passage explains how the ECG systematically measures and records the 'wave of excitation' that occurs within the heart in three distinct steps, spreading from the SA node to the AV node. This summary effectively captures the main focus of the passage. Option A is incorrect because it only mentions the detection of electric currents in the body and recognizing abnormalities by medical staff, missing the key information about the 'wave of excitation' and its stages. Option B is incorrect as it focuses solely on the measurement and recording of unique electric currents on the body's surface, neglecting the specific process described in the passage. Option D is also incorrect as it provides a general description of how the ECG measures electric currents without emphasizing the specific stages of the 'wave of excitation' as detailed in the passage.
What is the writer's primary purpose in writing this essay?
- A. To inform the reader about the dangers of high blood pressure
- B. To inform the reader how high blood pressure leads to a higher risk of heart attack
- C. To inform the reader how the cardiovascular system regulates blood pressure
- D. To persuade the reader that controlling one's blood pressure is important
Correct Answer: C
Rationale: The primary purpose of the essay is to inform the reader about how the cardiovascular system regulates blood pressure. The essay provides detailed explanations about the components of the cardiovascular system that regulate blood pressure, such as baroreceptors, chemoreceptors, and the kidneys. Choices A and B are incorrect because the essay does not focus on discussing the dangers of high blood pressure or its correlation with a higher risk of heart attack. Choice D is incorrect as the essay does not aim to persuade the reader to control their blood pressure but rather to educate them on the regulatory mechanisms of the cardiovascular system.
What is the meaning of the word 'evolved' in the first paragraph?
- A. To spread
- B. To gradually develop
- C. To revolve
- D. To shift
Correct Answer: B
Rationale: In the context of the given extract, 'evolved' means to gradually develop. The systems in the body have evolved over time, indicating a gradual development and adaptation. 'To spread,' 'to revolve,' and 'to shift' do not capture the idea of a gradual development as portrayed in the text, making them incorrect choices.
What is a major difference in the way baroreceptors and chemoreceptors work from the way the kidneys work?
- A. Baroreceptors and chemoreceptors send impulses from the arteries, while the kidneys control blood volume.
- B. Baroreceptors and chemoreceptors both work to help maintain blood volume, whereas the kidneys take care of salts, water, and waste removal.
- C. Baroreceptors and chemoreceptors must work together to control blood pressure, whereas the kidneys work with the adrenal cortex.
- D. Baroreceptors and chemoreceptors are both located near the adrenal cortex, whereas the kidneys are located near the heart.
Correct Answer: A
Rationale: The correct answer is A. Baroreceptors and chemoreceptors send impulses from the arteries, while the kidneys control blood volume. Baroreceptors and chemoreceptors are responsible for monitoring blood pressure by sensing changes in pressure, oxygen levels, carbon dioxide levels, and pH within the arteries. They send out impulses to raise or lower blood pressure accordingly. On the other hand, the kidneys play a crucial role in regulating blood volume by absorbing salts and water and removing waste products. This key difference highlights that while baroreceptors and chemoreceptors are involved in monitoring and regulating blood pressure, the kidneys primarily focus on controlling blood volume. Choice B is incorrect because it inaccurately states that baroreceptors and chemoreceptors help maintain blood volume, which is not their primary function. Choice C is incorrect as it provides an inaccurate comparison between the roles of baroreceptors, chemoreceptors, and the kidneys. Choice D is incorrect as it wrongly associates the location of baroreceptors and chemoreceptors with the adrenal cortex, which is not accurate.