搜题请搜索小程序“爱下问搜题”
问题 单项选择题

兴奋性突触后电位的电变化是

A．极化

B．去极化

C．超极化

D．反极化

E．复极化

答案

参考答案：B

解析：
突触后电位包括EPSP与IPSP，它们都是局部电位，两者的鉴别是常考点，如下：

兴奋性突触后电位(EPSP)抑制性突触后电位(IPSP)
神经递质作用于突触后膜的递质为兴奋性递质作用突触后膜的递质为抑制性递质
后膜电位递质作用后，突触后膜发生去极化递质作用后，突触后膜发生超极化
兴奋性突触后神经元对刺激兴奋性升高对其他刺激兴奋性降低
产生机制递质作用于后膜，后膜对Na+和K+通透性增高，导致突触后膜去极化后膜对Cl-通透性升高，Cl-内流，超极化
K+通透性增高及Na+、Ca2+通道关闭
特点EPSP可以总和，为局部电位EPSP可以总和，为局部电位
结果突触后神经元容易兴奋突触后神经元更不容易兴奋

选择题

2006年普通高等学校招生全国统一考试安徽卷，34） Catherine bought a postcard of the place she was visiting, addressed       to        and then posted it at the nearby post office．

A．it; her

B．it; herself

C．herself; her

D．herself; herself
查看答案
填空题

Questions 9-18


·Read the following article and answer questions 9-18 on the next page.

Apples: The Live Longer Fruit


0. Apples have been a product of healthy eating for many years, and the often-repeated line of an apple a day keeping the doctor away is far from a myth. Apples really do have a wonderful variety of nutritional benefits, and are a tasty addition to any diet of good health and longevity. Below is a list of the top five benefits of making apples a standard part of your daily diet.
1. Pectin (果胶) is a source of dietary fiber and a very handy nutrient to have in one’s diet. While it is also found in oranges, plums, and other fruits, apples have the highest concentration of them all. Pectin works to increase the stool’s volume and resistance of fluids and is therefore helpful in treating constipation, diarrhea, and generally improving the health of the bowels (肠) .
2. A study on nutrition and heart disease found that eating three apples a day for three months can help you to drop your cholesterol by at least 20 points. How does this happen Apple pectin, that miraculous source of dietary fiber, helps to draw bad LDL cholesterol out of the system. Not only that, but the antioxidant quercetin(栎皮酮)that is found in apples inhibits the LDL cholesterol from even accumulating in the body’s bloodstream.
3. The high amounts of quercetin, other flavonoids (类黄酮) , and phytochemicals (植物化学 因子) found in this fruit deliver potent antioxidant activity to all who eat an apple, and with that inhibit the actions of free radicals. In addition, the phytochemicals may act against cancer-causing substances, which will likewise help to prevent cancer. This means that apple eating prevents cancer of the prostate (前列腺) and lung, as well as other parts of the body.
4. There may have been many generations of explorers that sought the fountain of youth, but all they had to do was fight the daily stresses of life with a tasty apple! The phytochemicals that come from the bright colors you find in the skins of your favorite apple variety, along with aiding the apple’s ability to lower cholesterol and fight cancer, also inhibits the onset of diabetes, high blood pressure, heart disease, and other conditions that lead to potentially weakening situations in old age.
5. If keeping a full head of hair will help you to age more gracefully, then chow down on some apples. Chinese medicine considers hair loss to be a sign of a reduced kidney essence, and apples are on the list of fruits and vegetables that will help you to restore this essence and nourish the blood that flows to your hair follicles (毛囊) .

Questions 9-13


·For questions 9-13, choose the best title for each paragraph from the box below.
·For each numbered paragraph (1-5). mark one letter (A -G) on the Answer Sheet.
·Do not mark any letter twice.
  • A. Apples lower cholesterol.
  • B. Apples benefit young and old.
  • C. Apples slow the aging process.
  • D. Apples reduce the risk of cancer.
  • E. Apples help to prevent hair loss.
  • F. Apples enrich people’s diet.
  • G. Apples improve the bowels.


Paragraph 1: ______
查看答案