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Beep!…Beep!…Beep! is the audible rhythmic sound made as the strength of the heart muscle is measured. The signal cadence has a characteristic record that varies in every individual. This record is called an electrocardiogram, or ECG.
In the body, an array of systemic neural responses constantly occur, emitting electric currents. The electric currents can be detected on the surface of the body, and if a person is hooked to an amplifier, these impulses are recorded by an electrocardiograph. Most of the information obtained is about the heart because the heart sends out electric currents in waves. This “wave of excitation†spreads through the heart wall and is accompanied by electric changes.
The wave takes place in three distinct steps. Initially, the “wave of excitation†accompanied by an electric change lasts for approximately 1 to 2 seconds after the contraction of the cardiac muscle. The electric impulses are discharged rhythmically from the sinoatrial (SA) node, the pacemaker of the heart. This spread of excitation over the muscle of the atrium indicates that the atrium has contracted. Next, the peak of the ECG reading is due to the atrioventricular (AV) node, causing the ventricle to become excited. Finally, the ventricles relax, and any changes in the wave indicate to trained medical staff any abnormalities within the heart.
What is the author's primary purpose in writing the essay?
- A. To persuade the reader to have an ECG
- B. To entertain the reader with a heartwarming story
- C. To inform the reader how an electrocardiograph reads the electric currents emitted by the heart
- D. To analyze the difference between the SA node and the AV node
Correct Answer: C
Rationale: The author's primary purpose in writing the essay is to inform the reader about how an electrocardiograph reads the electric currents emitted by the heart. Choice A is incorrect because there is no attempt to persuade the reader to have an ECG. Choice B is incorrect because the essay is focused on providing information rather than entertaining with a heartwarming story. Choice D is incorrect as the essay does not primarily analyze the difference between the SA node and the AV node; instead, it focuses on explaining how an electrocardiograph reads electric currents from the heart.
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Beep!…Beep!…Beep! is the audible rhythmic sound made as the strength of the heart muscle is measured. The signal cadence has a characteristic record that varies in every individual. This record is called an electrocardiogram, or ECG.In the body, an array of systemic neural responses constantly occur, emitting electric currents. The electric currents can be detected on the surface of the body, and if a person is hooked to an amplifier, these impulses are recorded by an electrocardiograph. Most of the information obtained is about the heart because the heart sends out electric currents in waves. This “wave of excitation†spreads through the heart wall and is accompanied by electric changes. The wave takes place in three distinct steps.Initially, the “wave of excitation†accompanied by an electric change lasts for approximately 1 to 2 seconds after the contraction of the cardiac muscle. The electric impulses are discharged rhythmically from the sinoatrial (SA) node, the pacemaker of the heart. This spread of excitation over the muscle of the atrium indicates that the atrium has contracted.Next, the peak of the ECG reading is due to the atrioventricular (AV) node, causing the ventricle to become excited.<p>Finally, the ventricles relax, and any changes in the wave indicate to trained medical staff any abnormalities within the heart.
Which statement is not listed as a detail within the passage?
- A. Changes in the ECG are typically used for the diagnosis of abnormal cardiac rhythm.
- B. The signal has a characteristic record called the electrocardiogram.
- C. The 'wave of excitation' starts at the SA node.
- D. The 'wave of excitation' spreads through the heart wall and is accompanied by electric changes.
Correct Answer: A
Rationale: The corrected statement should be: Changes in the ECG are not typically used for the diagnosis of abnormal cardiac rhythm. The passage mentions that the heart sends out electric currents in waves, and the 'wave of excitation' spreads through the heart wall accompanied by electric changes. It details the process of how the heart's electric impulses are recorded and how abnormalities can be detected. However, it does not state that ECG changes are specifically used for diagnosing abnormal cardiac rhythms. Choice A is the correct answer because it misrepresents the information provided in the passage. Choices B, C, and D are all supported by the passage and align with the details mentioned regarding the electrocardiogram and the wave of excitation in the heart.
The body is composed of systems that have evolved and diversified in order to maintain the natural functions and processes they regulate.
One such system that has these regulators is the body's cardiovascular system. The body's pump, which regulates the flow of vitally needed oxygen to all cells of the body, as well as the discard of carbon dioxide and other waste products, is the heart. Because blood pressure varies at different points within the body, differing components are needed to keep the body's blood pressure regulated. Three of the basic components are baroreceptors, chemoreceptors, and the kidneys.
Baroreceptors are stretch receptors composed of fine branching nerve endings and are contained along the walls of the arteries near the heart and in other areas of the body as well. Impulses are related to this stretching along the arterial walls, which causes these baroreceptors to send out even more impulses to the heart, arteries, and veins, causing the blood pressure to go either up or down.
Chemoreceptors are located along the walls of the arteries and monitor changes in oxygen level, carbon dioxide, and pH. Just think! A fall in oxygen causes receptors to send impulses to raise the blood pressure. The kidneys play a role in regulating blood pressure by absorbing salts and water and removing wastes. Hormones secreted by the adrenal cortex cause the kidney to keep or let go of any salt and water. This has an influence on blood volume and consequently on blood pressure.
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.
Searching for medical information can be confusing, especially for first-timers. However, if you are patient and stick to it, you can find a wealth of information. Your community library is a good place to start your search for medical information. Before going to the library, you may find it helpful to make a list of topics you want information about and questions you have. Your list of topics and questions will make it easier for the librarian to direct you to the best resources. Many community libraries have a collection of basic medical references. These references may include medical dictionaries or encyclopedias, drug information handbooks, basic medical and nursing textbooks, and directories of physicians and medical specialists (listings of doctors). You may also find magazine articles on a certain topic. Look in the Reader's Guide to Periodical Literature for articles on health and medicine from consumer magazines.Infotrac, a CD-ROM computer database available at libraries or on the Web, indexes hundreds of popular magazines and newspapers, as well as medical journals such as the Journal of the American Medical Association and New England Journal of Medicine.Your library may also carry searchable computer databases of medical journal articles, including MEDLINE/PubMed or the Cumulative Index to Nursing and Allied Health Literature. Many of the databases or indexes have abstracts that provide a summary of each journal article. Although most community libraries don't have a large collection of medical and nursing journals, your librarian may be able to get copies of the articles you want. Interlibrary loans allow your librarian to request a copy of an article from a library that carries that particular medical journal. Your library may charge a fee for this service. Articles published in medical journals can be technical, but they may be the most current source of information on medical topics.
What is the meaning of the word 'technical' as it is used in the fourth paragraph?
- A. requiring expert knowledge
- B. incomplete
- C. foreign
- D. plagiarized
Correct Answer: A
Rationale: The correct answer is 'A: requiring expert knowledge.' In the context provided, 'technical' refers to articles that demand expert knowledge to understand. The passage mentions that articles published in medical journals can be technical, meaning they are complex and require specialized expertise to comprehend. Choice B, 'incomplete,' is incorrect as 'technical' does not imply incompleteness. Choices C and D, 'foreign' and 'plagiarized,' are also incorrect as they do not align with the context of the passage.
Beep!…Beep!…Beep! is the audible rhythmic sound made as the strength of the heart muscle is measured. The signal cadence has a characteristic record that varies in every individual. This record is called an electrocardiogram, or ECG.In the body, an array of systemic neural responses constantly occur, emitting electric currents. The electric currents can be detected on the surface of the body, and if a person is hooked to an amplifier, these impulses are recorded by an electrocardiograph. Most of the information obtained is about the heart because the heart sends out electric currents in waves. This “wave of excitation†spreads through the heart wall and is accompanied by electric changes. The wave takes place in three distinct steps.Initially, the “wave of excitation†accompanied by an electric change lasts for approximately 1 to 2 seconds after the contraction of the cardiac muscle. The electric impulses are discharged rhythmically from the sinoatrial (SA) node, the pacemaker of the heart. This spread of excitation over the muscle of the atrium indicates that the atrium has contracted.Next, the peak of the ECG reading is due to the atrioventricular (AV) node, causing the ventricle to become excited.<p>Finally, the ventricles relax, and any changes in the wave indicate to trained medical staff any abnormalities within the heart.
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.
The body is composed of systems that have evolved and diversified in order to maintain the natural functions and processes they regulate. One such system that has these regulators is the body's cardiovascular system. The body's pump, which regulates the flow of vitally needed oxygen to all cells of the body, as well as the discard of carbon dioxide and other waste products, is the heart. Because blood pressure varies at different points within the body, differing components are needed to keep the body's blood pressure regulated. Three of the basic components are baroreceptors, chemoreceptors, and the kidneys.<p>Baroreceptors are stretch receptors composed of fine branching nerve endings and are contained along the walls of the arteries near the heart and in other areas of the body as well. Impulses are related to this stretching along the arterial walls, which causes these baroreceptors to send out even more impulses to the heart, arteries, and veins, causing the blood pressure to go either up or down.Chemoreceptors are located along the walls of the arteries and monitor changes in oxygen level, carbon dioxide, and pH. Just think! A fall in oxygen causes receptors to send impulses to raise the blood pressure.The kidneys play a role in regulating blood pressure by absorbing salts and water and removing wastes. Hormones secreted by the adrenal cortex cause the kidney to keep or let go of any salt and water. This has an influence on blood volume and consequently on blood pressure.
What is the best summary of this passage?
- A. The heart regulates oxygen flow and waste disposal, with the kidneys aiding in salt and water absorption.
- B. The cardiovascular system regulates blood pressure through baroreceptors, chemoreceptors, and the kidneys.
- C. Baroreceptors send impulses to regulate blood pressure by affecting the heart, arteries, and veins.
- D. Chemoreceptors monitor oxygen levels to impact blood pressure.
Correct Answer: B
Rationale: The correct answer is B because it provides a comprehensive summary of the passage, explaining how the cardiovascular system regulates blood pressure through baroreceptors, chemoreceptors, and the kidneys. Choice A is incorrect as it only focuses on the heart and kidneys without mentioning the broader cardiovascular system. Choice C is incorrect as it solely emphasizes the role of baroreceptors in regulating blood pressure. Choice D is incorrect as it oversimplifies the role of chemoreceptors in monitoring oxygen levels without mentioning their impact on blood pressure regulation.