当血流通过下列哪一部位时，blood pressure的降落最大？A．主动脉和大动脉B．小动脉和微动脉C．毛细血管D．微静脉和小静脉
当血流通过下列哪一部位时，blood pressure的降落最大？
A．主动脉和大动脉
B．小动脉和微动脉
C．毛细血管
D．微静脉和小静脉
参考答案和解析
C
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Text 3Under certain circumstances, the human body must cope with gases at greater-than-normal atmospheric pressure. For example, gas pressures increase rapidly during a dive made with scuba gear because the breathing equipment allows divers to stay underwater longer and dive deeper.The pressure exerted on the human body increases by 1 atmosphere for every 10 meters of depth in seawater, so that at 30 meters in seawater a diver is exposed to a pressure of about 4 atmospheres. The pressure of the gases being breathed must equal the external pressure applied to the body, otherwise breathing is very difficult. Therefore all of the gases in the air breathed by a scuba diver at 40 meters are present at five times their usual pressure. Nitrogen, which composes 80 per cent of the air we breathe, usually causes a balmy feeling of well-being at this pressure. At a depth of 5 atmospheres, nitrogen causes symptoms resembling alcohol intoxication, known as nitrogen narcosis. Nitrogen narcosis apparently results from a direct effect on the brain of the large amounts of nitrogen cause under these pressurized helium does not exert a similar narcotic effect.As a scuba diver descends, the pressure of nitrogen in the lungs increases. Nitrogen then diffuses from the lungs to the blood, and from the blood to body tissues. The reverse occurs when the diver surfaces; the nitrogen pressure in the lungs falls and the nitrogen diffuses from the tissues into the blood, and from the blood into the lungs. If the return to the surface is too rapid, nitrogen in the tissues and blood cannot diffuse out rapidly enough and nitrogen bubbles are formed. They can cause severe pains, particularly around the joints.Another complication may result if the breath is held during ascent. During ascent from a depth of 10 meters, the volume of air in the lungs will double because the air pressure at the surface is only half of what it was at 10 meters. This change in volume may cause the lungs to distend and even rupture. This condition is called air embolism. To avoid this event, a diver must ascend slowly, never at a rate exceeding the rise of the exhaled air bubbles, and must exhale during as- cent.31. What does the passage mainly discuss?A) The equipment divers use.B) The effects of pressure on gases in the human body.C) How to prepare for a deep dive.D) The symptoms of nitrogen bubbles in the bloodstream.
共用题干Hypertension Drugs Found to Cut Risk of StrokeAustralian doctors declared Monday that a cocktail of simple antihypertensive drugs can lower the risk of patients suffering a repeat stroke by more than a third.This is the result of their research.The research, presented at a medical conference in Italy over the weekend,has been valued highly as a major breakthrough in stroke prevention.Strokes kill 5 million people a year,and more than 15 million suffer non-fatal strokes that often leave them with useless limbs,slurred speech and other serious disabilities.One in five stroke survivors goes on to have a second,often fatal,stroke within five years of the first.An international six-year study of 6,100 patients directed from Sydney University found that by taking two blood pressure-lowering drugs,the risk of secondary strokes can be reduced by up to 40 percent.Even taking one of the commonly available drugs can cut the risk by a third,the study said.The drugs are the diuretic indapamide ( 吲达帕胺）and the ACE inhibitor perindopril , better known by its brand name Cover- syl.The combination was effective even in patients who did not have high blood pressure,the researchers said.They even found that the risk of another stroke could be cut by three quarters among the one-in-ten pa- tients who had suffered a cerebral hemorrhage（出血）, the worst type of stroke , where there is direct bleeding into the brain.Stephen McMahon,who presented the research at the Milan congress of the European Society of Hypertension,said about 50 million people were alive who had suffered at least one stroke."If most of those patients were able to get access to this treatment,it would result in maybe the avoidance of half a million strokes a year,"the professor told Australia's ABC Radio.McMahon said doctors had long known that lowering the blood pressure of those with hypertension could help prevent strokes."What we have shown for the first time is that it does not really matter what your blood pressure is;if you have had a stroke,then lowering blood pressure will produce large benefits,to begin with-even for people whose blood pressure is average or below average,"he said.McMahon said the Milan gathering had heralded the research as a"major breakthrough in the care of patients with strokes-perhaps the biggest step forward that we have made in the last couple of decades."What patients among those who have a stroke will benefit greatly from taking blood pressure-lowering drugs?A:Those whose blood pressure is high.B:Those whose blood pressure is average.C:Those whose blood pressure is below average.D:All of the above.
资料：Why is Salt Bad for You?FRANK LE CLAIR, a 58-year-old provincial government employee living in Winnipeg, had no idea that his blood pressure was too high. While out of town last winter, he came down with a cold and a sore throat and decided to see a local doctor.Apart from checking his cold symptoms, the doctor also gave him a general health-check. The doctor found that Frank’s blood pressure was higher than normal and advised him to see his regular physician as soon as he got home.Le Clair’s physician referred him to the Winnipeg Health Sciences Centre, where dietitians told him that he might be able to control his blood pressure by changing his lifestyle rather than by taking drugs. People with high blood pressure have to control or eliminate four elements: smoking, drinking, food quantities and salt. Le Clair doesn’t smoke or drink, but there were some changes he could make in the other two categories.The most conclusive evidence so far that a high-salt diet is bad for you is the “Intersalt” study, involving 10,000 people in 32 countries. It measured the relationship between urinary sodium excretion -- a direct measure of salt consumption -- and blood pressure. The study found that populations with the lowest sodium excretion also have the lowest blood pressures.Recent studies have shown that “salt sensitivity” is a major factor in the relationship between a high-salt diet and hypertension. And hypertension is a risk factor for two of the biggest killers in this country: coronary heart disease and stroke. Frank Le Clair’s high blood pressure was discovered by chance. There are no warning symptoms -- high blood pressure is known as the silent killer.A high-salt intake triggers a vicious cycle. Those who are used to a lot of salt in their food find they need increasing amounts to be able to continue to taste its flavour --- the more salt they eat, the more they want. It is also an aggravating factor in osteoporosis and is closely linked to stomach cancer. A high salt intake can be dangerous for people with conditions that are aggravated by fluid retention, such as hepatitis, liver or kidney problems.According to the passage, the major causes of death in Frank Le Clair’s country are ______.A.hypertension and high blood pressureB.heart disease and strokeC.liver damage and kidney problemsD.osteoporosis and stomach cancer
资料：Why is Salt Bad for You?FRANK LE CLAIR, a 58-year-old provincial government employee living in Winnipeg, had no idea that his blood pressure was too high. While out of town last winter, he came down with a cold and a sore throat and decided to see a local doctor.Apart from checking his cold symptoms, the doctor also gave him a general health-check. The doctor found that Frank’s blood pressure was higher than normal and advised him to see his regular physician as soon as he got home.Le Clair’s physician referred him to the Winnipeg Health Sciences Centre, where dietitians told him that he might be able to control his blood pressure by changing his lifestyle rather than by taking drugs. People with high blood pressure have to control or eliminate four elements: smoking, drinking, food quantities and salt. Le Clair doesn’t smoke or drink, but there were some changes he could make in the other two categories.The most conclusive evidence so far that a high-salt diet is bad for you is the “Intersalt” study, involving 10,000 people in 32 countries. It measured the relationship between urinary sodium excretion -- a direct measure of salt consumption -- and blood pressure. The study found that populations with the lowest sodium excretion also have the lowest blood pressures.Recent studies have shown that “salt sensitivity” is a major factor in the relationship between a high-salt diet and hypertension. And hypertension is a risk factor for two of the biggest killers in this country: coronary heart disease and stroke. Frank Le Clair’s high blood pressure was discovered by chance. There are no warning symptoms -- high blood pressure is known as the silent killer.A high-salt intake triggers a vicious cycle. Those who are used to a lot of salt in their food find they need increasing amounts to be able to continue to taste its flavour --- the more salt they eat, the more they want. It is also an aggravating factor in osteoporosis and is closely linked to stomach cancer. A high salt intake can be dangerous for people with conditions that are aggravated by fluid retention, such as hepatitis, liver or kidney problems.Frank Le Clair was advised by ______ to adjust his lifestyle.A.his family doctorB.a heart specialistC.research scientistsD.a nutrition expert
资料：Why is Salt Bad for You?FRANK LE CLAIR, a 58-year-old provincial government employee living in Winnipeg, had no idea that his blood pressure was too high. While out of town last winter, he came down with a cold and a sore throat and decided to see a local doctor.Apart from checking his cold symptoms, the doctor also gave him a general health-check. The doctor found that Frank’s blood pressure was higher than normal and advised him to see his regular physician as soon as he got home.Le Clair’s physician referred him to the Winnipeg Health Sciences Centre, where dietitians told him that he might be able to control his blood pressure by changing his lifestyle rather than by taking drugs. People with high blood pressure have to control or eliminate four elements: smoking, drinking, food quantities and salt. Le Clair doesn’t smoke or drink, but there were some changes he could make in the other two categories.The most conclusive evidence so far that a high-salt diet is bad for you is the “Intersalt” study, involving 10,000 people in 32 countries. It measured the relationship between urinary sodium excretion -- a direct measure of salt consumption -- and blood pressure. The study found that populations with the lowest sodium excretion also have the lowest blood pressures.Recent studies have shown that “salt sensitivity” is a major factor in the relationship between a high-salt diet and hypertension. And hypertension is a risk factor for two of the biggest killers in this country: coronary heart disease and stroke. Frank Le Clair’s high blood pressure was discovered by chance. There are no warning symptoms -- high blood pressure is known as the silent killer.A high-salt intake triggers a vicious cycle. Those who are used to a lot of salt in their food find they need increasing amounts to be able to continue to taste its flavour --- the more salt they eat, the more they want. It is also an aggravating factor in osteoporosis and is closely linked to stomach cancer. A high salt intake can be dangerous for people with conditions that are aggravated by fluid retention, such as hepatitis, liver or kidney problems.Recent research studies have shown that ______.A.salt consumption leads to a strokeB.sodium excreted in urine is a measure of salt intakeC.an increase in blood pressure causes an increase in salt consumptionD.the higher the sodium in urine, the greater the chance of hypertension
共用题干Yoga May Help Ease High Blood PressurePeople who follow the ancient practice of yoga may be getting an added health boost,with a new study suggesting it can fight high blood pressure一also known as hypertension."This study confirms many people's feelings that exercise may be useful in the control of hypertension,"said Dr. Howard."Yoga would be a useful adjunct in the lowering of blood pressure in certain populations."_________(46)Although the study couldn't prove a cause-and-effect relationship,doing yoga two to three times a week was associated with an average drop in blood pressure readings from 133/ 80 to 130/77,the researchers said.In comparison,the average decrease in blood pressure was smaller(134/83 to 132/82)among people who ate a special diet but did not do yoga.In a bit of a surprise,doing yoga in tandem with a special diet did not outperform doing yoga alone.___________(47)Dr. Howard said the study shows that"yoga can have a favorable effect" on hypertension. ________(48)"But some large population studies have suggested that changes of this magnitude could have very significant long-term benefits."___________(49)including its relatively short length and the fact that most participants were young and had milder forms of high blood pressure,Dr. Howard said.__________(50)"Yoga,along with deep breathing exercises,meditation and inner reflection,is a good adjunctive and integrative cardiovascular approach to better health,including lowering blood pressure,as this data suggests,"said Dr. David Friedman.__________(46)A:The amount of change was small,he said.B:Another expert agreed that the ancient Indian practice of yoga might ease hypertension.C:In the study,researchers tracked 58 women and men,aged 38 to 62,for six months.D:Yoga is proved to be effective in lowering high blood pressure.E:The study did have some limitations.F: This may be because doing both required a greater amount of time,making it more difficult for participants to stick with their regimens.
单选题NNK is usually considered to be one of the direct cause’s of ______.AasthmaBlung cancerCheart attacksDhigh blood pressure
单选题If you have high blood pressure, you should _____ eating too much salt.AescapeBsuggestCavoidDrelieve
单选题As is well known, eating too much fat can _____ heart disease and cause high blood pressure.Aadd toBattend toCcontribute toDapply to
单选题If you have high blood pressure, you should_____eating too much salty food.AescapeBsuggestCavoidDrelax
判断题An unhealthy lifestyle, which may lead to disorders of the blood fats, development of diabetes or pre-diabetes, and the onset or aggravation of high blood pressure, can increase the chances of atherosclerosis.A对B错