| Core | Supplement |
|---|---|
| 1 Describe a pathogen as a disease-causing organism | |
| 2 Describe a transmissible disease as a disease in which the pathogen can be passed from one host to another | |
| 3 State that a pathogen is transmitted: (a) by direct contact, including through blood and other body fluids (b) indirectly, including from contaminated surfaces, food, animals and air | |
| 4 Describe the body defences, limited to: skin, hairs in the nose, mucus, stomach acid and white blood cells | 6 Describe active immunity as defence against a pathogen by antibody production in the body |
| 5 Explain the importance of the following in controlling the spread of disease: (a) a clean water supply (b) hygienic food preparation (c) good personal hygiene (d) waste disposal (e) sewage treatment (details of the stages of sewage treatment are not required) | 7 State that each pathogen has its own antigens, which have specific shapes |
| 8 Describe antibodies as proteins that bind to antigens leading to direct destruction of pathogens or marking of pathogens for destruction by phagocytes | |
| 9 State that specific antibodies have complementary shapes which fit specific antigens | |
| 10 Explain that active immunity is gained after an infection by a pathogen or by vaccination | |
| 11 Outline the process of vaccination: (a) weakened pathogens or their antigens are put into the body (b) the antigens stimulate an immune response by lymphocytes which produce antibodies (c) memory cells are produced that give long-term immunity | |
| 12 Explain the role of vaccination in controlling the spread of diseases | |
| 13 Explain that passive immunity is a short-term defence against a pathogen by antibodies acquired from another individual, including across the placenta and in breast milk | |
| 14 Explain the importance of breast-feeding for the development of passive immunity in infants | |
| 15 State that memory cells are not produced in passive immunity | |
| 16 Describe cholera as a disease caused by a bacterium which is transmitted in contaminated water | |
| 17 Explain that the cholera bacterium produces a toxin that causes secretion of chloride ions into the small intestine, causing osmotic movement of water into the gut, causing diarrhoea, dehydration and loss of ions from the blood |
疾病与免疫
IGCSE 生物 · 第 10 主题
10.1
疾病与免疫
大纲
来源:剑桥国际大纲
一个病原体(pathogen)是一个引起疾病(disease)的生物。一种传染病(transmissible disease)是病原体能从一个宿主(host)传到另一个的疾病。
词汇表
训练
| 英文 | 中文 | 拼音 |
|---|---|---|
| pathogen | 病原体 | bìng yuán tǐ |
| disease | 疾病 | jí bìng |
| transmissible disease | 传染病 | chuán rǎn bìng |
| host | 宿主 | sù zhǔ |
10.1
病原体如何传播
一个病原体以两种主要方式传播(transmitted):
- 通过直接接触(direct contact)——例如通过血液和其他体液(body fluids)。
- 间接地——例如从污染(contaminated)的表面、食物、动物或空气。
词汇表
训练
| 英文 | 中文 | 拼音 |
|---|---|---|
| transmitted | 传播 | chuán bō |
| direct contact | 直接接触 | zhí jiē jiē chù |
| body fluids | 体液 | tǐ yè |
| contaminated | 污染 | wū rǎn |
10.1
身体的防御
你的身体有几个把病原体挡在外面或摧毁它们的防御(defences):
- 皮肤——一个覆盖并保护身体的屏障。
- 鼻子里的毛——困住你吸入的空气中的尘埃和病原体。
- 黏液(mucus)——气道中困住病原体的黏性液体。
- 胃酸(stomach acid)——杀死你食物中大多数的病原体。
- 白细胞(white blood cells)——找到并摧毁任何进入内部的病原体。
探索
Pathogen defence route
Follow how the body blocks, detects and removes pathogens.
词汇表
训练
| 英文 | 中文 | 拼音 |
|---|---|---|
| defences | 防御 | fáng yù |
| mucus | 黏液 | nián yè |
| stomach acid | 胃酸 | wèi suān |
| white blood cells | 白细胞 | bái xì bāo |
10.1
控制疾病传播
好的公共卫生阻止疾病传播:
- 一个干净的水供应,所以饮用水不携带病原体。
- 卫生的(hygienic)食物准备和好的个人卫生,如洗你的手。
- 适当的废物处理和污水处理(sewage treatment),所以废物不污染水或食物。
词汇表
训练
| 英文 | 中文 | 拼音 |
|---|---|---|
| hygienic | 卫生 | wèi shēng |
| sewage treatment | 污水处理 | wū shuǐ chǔ lǐ |
10.1
免疫(拓展)
Antigens and antibodies
每个病原体在它的表面携带抗原(antigens),而每种抗原有它自己的特殊形状。
抗体(antibodies)是淋巴细胞(lymphocytes,一种白细胞)制造的蛋白质(proteins)。一个抗体有一个与一个抗原互补(complementary)的形状,所以它只契合那个抗原。当抗体结合到一个病原体的抗原时,它们要么直接摧毁病原体,要么标记它,使吞噬细胞(phagocytes)摧毁它。
Active immunity and vaccination
主动免疫(active immunity)是你自己的身体产生抗体制造的保护。你在一次感染后,或在疫苗接种(vaccination)后获得它。
疫苗接种像这样工作:
- 减弱的病原体,或只是它们的抗原,被放进身体;它们不能使你生病。
- 抗原使你的淋巴细胞产生抗体。
- 身体也制造停留多年的记忆细胞(memory cells)。
若真实的病原体后来进入,记忆细胞非常快地制造抗体,所以你不会生病。这给长期保护。若一个群里的大多数人被接种,疾病就不能容易地传播。
例题。 第一次接种疫苗后,抗体水平缓慢上升并保持在低位。第二次接种同一疫苗后,抗体上升更快,并达到高得多的水平。请解释。第一次接种时,身体没有针对该抗原的记忆细胞,要花时间找到合适的淋巴细胞并让它增殖 - 所以反应又慢又小。第二次接种遇到的是第一次留下的记忆细胞,它们立刻识别该抗原,所以抗体产生得更早、数量多得多。得分点是记忆细胞:写"身体已经习惯了"得不到分。
Passive immunity
被动免疫(passive immunity)是来自另一个身体、不是你自己的身体制造的抗体的保护。例如,一个婴儿跨胎盘(placenta)和在母乳(breast milk)中从它的母亲接收抗体。这就是为什么母乳喂养(breast-feeding)帮助保护婴儿(infants)。被动免疫只是短期的,因为没有记忆细胞被制造。
词汇表
训练
| 英文 | 中文 | 拼音 |
|---|---|---|
| antigens | 抗原 | kàng yuán |
| antibodies | 抗体 | kàng tǐ |
| proteins | 蛋白质 | dàn bái zhì |
| lymphocytes | 淋巴细胞 | lín bā xì bāo |
| complementary | 互补 | hù bǔ |
| phagocytes | 吞噬细胞 | tūn shì xì bāo |
| active immunity | 主动免疫 | zhǔ dòng miǎn yì |
| vaccination | 疫苗接种 | yì miáo jiē zhǒng |
| memory cells | 记忆细胞 | jì yì xì bāo |
| passive immunity | 被动免疫 | bèi dòng miǎn yì |
| placenta | 胎盘 | tāi pán |
| breast milk | 母乳 | mǔ rǔ |
| breast-feeding | 母乳喂养 | mǔ rǔ wèi yǎng |
| infants | 婴儿 | yīng ér |
10.1
霍乱(拓展)
霍乱(cholera)是一种由在污染的水中传播的一个细菌(bacterium)引起的疾病。霍乱细菌制造一个毒素(toxin)。这个毒素使氯离子(chloride ions)被泵入小肠(small intestine)。水随即通过渗透(osmosis)移入肠道。结果是腹泻(diarrhoea)、脱水(dehydration,水的流失)和血液中离子(ions)的流失。
词汇表
训练
| 英文 | 中文 | 拼音 |
|---|---|---|
| cholera | 霍乱 | huò luàn |
| bacterium | 细菌 | xì jūn |
| toxin | 毒素 | dú sù |
| chloride ions | 氯离子 | lǜ lí zi |
| small intestine | 小肠 | xiǎo cháng |
| osmosis | 渗透 | shèn tòu |
| diarrhoea | 腹泻 | fù xiè |
| dehydration | 脱水 | tuō shuǐ |
| ions | 离子 | lí zi |
10.1
考试技巧
- 病原体 = 引起疾病的生物。传染性 = 能通过直接接触或间接地在宿主之间传递。
- 学习五个身体防御:皮肤、鼻毛、黏液、胃酸、白细胞。
- 一个抗体的形状与一个抗原互补(像一个酶和它的底物)。
- 主动免疫(来自感染或疫苗接种)制造记忆细胞 → 长期。被动免疫(胎盘、母乳)制造没有记忆细胞 → 短期。
- 霍乱:毒素 → 氯离子进入肠道 → 水通过渗透进入 → 腹泻和脱水。
本主题的互动课程
逐步学习,并即时检测练习。