Nokea
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.
You may also like to solve these questions
Have you ever wondered why the whistle of a traveling, distant locomotive predicts its approach several yards before anyone actually sees it? Or why an oncoming ambulance's screaming siren is heard momentarily several feet before the ambulance comes into full view, before it passes you, and why its siren is still heard faintly well after the ambulance is out of sight?What you are witnessing is a scientific phenomenon known as the Doppler Effect. What takes place is truly remarkable. In both of these instances, when the train or ambulance moves toward the sound waves in front of it, the sound waves are pulled closer together and have a higher frequency. In either instance, the listener positioned in front of the moving object hears a higher pitch. The ambulance and locomotive are progressively moving away from the sound waves behind them, causing the waves to be farther apart and to have a lower frequency. These fast-approaching modes of transportation distance themselves past the listener, who hears a lower pitch.
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.
Lub-dub! Lub-dub! Lub-dub! This sound is made by the rapid contracting and extending of the chamber doors on the inside of theheart. This ventricular contracting injects roughly 70 mL of blood into a vascular system with a given volume at differing pressure.Blood pressure refers to the pressure in the arterial system; and it is typically taken in the brachial artery of the arm because the pressure at different places along the circulatory route is different. Blood pressure is simply the force that the blood exerts in all directions within any given area and is the basis for the movement of blood from the heart, through the body, and back to the heart. This pressure is commonly expressed as a ratio of the systolic pressure over the diastolic pressure.The systolic pressure or “high peak†pressure takes place within the arterial system as ventricles contract and force blood into the arteries. The diastolic pressure or “low peak†pressure takes place within this arterial system just before the next ventricular contraction.An increase in blood pressure can occur if the arterial walls lose some of their elasticity with age or disease.
What is the meaning of the word 'elasticity' in the last paragraph?
- A. Something that is able to resist and be flexible
- B. Something that is like plastic
- C. Something that is dynamic and electrifying
- D. Something that is silly
Correct Answer: A
Rationale: 'Elasticity' refers to the ability of the arterial walls to resist and be flexible, which affects blood pressure. In the provided extract, it is mentioned that an increase in blood pressure can occur if the arterial walls lose some of their elasticity with age or disease. This demonstrates that elasticity refers to the property of being able to resist and be flexible, supporting choice A as the correct answer. The other choices, B, C, and D, do not accurately reflect the concept of elasticity in the context of arterial walls and blood pressure.
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.
Foodborne illnesses are contracted by eating food or drinking beverages contaminated with bacteria, parasites, or viruses. Harmful chemicals can also cause foodborne illnesses if they have contaminated food during harvesting or processing. Foodborne illnesses can cause symptoms ranging from upset stomach to diarrhea, fever, vomiting, abdominal cramps, and dehydration. Most foodborne infections are undiagnosed and unreported, though the Centers for Disease Control and Prevention estimates that every year about 76 million people in the United States become ill from pathogens in food. About 5,000 of these people die.Harmful bacteria are the most common cause of foodborne illness. Some bacteria may be present at the point of purchase. Raw foods are the most common source of foodborne illnesses because they are not sterile; examples include raw meat and poultry contaminated during slaughter. Seafood may become contaminated during harvest or processing. One in 10,000 eggs may be contaminated with Salmonella inside the shell. Produce, such as spinach, lettuce, tomatoes, sprouts, and melons, can become contaminated with Salmonella, Shigella, or Escherichia coli (E. coli). Contamination can occur during growing, harvesting, processing, storing, shipping, or final preparation. Sources of produce contamination vary, as these foods are grown in soil and can become contaminated during growth, processing, or distribution. Contamination may also occur during food preparation in a restaurant or a home kitchen. The most common form of contamination from handled foods is the calicivirus, also called the Norwalk-like virus.When food is cooked and left out for more than two hours at room temperature, bacteria can multiply quickly. Most bacteria don't produce an odor or change in color or texture, so they can be impossible to detect. Freezing food slows or stops bacteria's growth, but does not destroy the bacteria. The microbes can become reactivated when the food is thawed. Refrigeration also can slow the growth of some bacteria. Thorough cooking is required to destroy the bacteria.
What is the subject of the passage?
- A. foodborne illnesses
- B. the dangers of uncooked food
- C. bacteria
- D. proper food preparation
Correct Answer: A
Rationale: The correct answer is A: 'foodborne illnesses.' The passage discusses how foodborne illnesses are contracted by consuming contaminated food or beverages, the symptoms they can cause, common sources of contamination like bacteria, viruses, and chemicals, and preventive measures. While the passage mentions dangers associated with uncooked food, bacteria, and proper food preparation, the primary focus is on foodborne illnesses caused by various contaminants. Choice B, 'the dangers of uncooked food,' is incorrect as it is a narrower focus compared to the broader topic of foodborne illnesses. Choice C, 'bacteria,' is incorrect as it is one of the contaminants discussed in relation to foodborne illnesses but not the central subject of the passage. Choice D, 'proper food preparation,' is incorrect as it is mentioned in the passage but not as the main subject; rather, it is discussed as a preventive measure to avoid foodborne illnesses.
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 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.