4904403
Description
Flashcards by Mel Hughes , updated more than 1 year ago
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Created by Mel Hughes
over 8 years ago
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| Question | Answer |
| Pathogens | Microorganisms that cause infectious disease |
| Bacteria | - Bacteria are very small single-celled organisms. - Not all cause disease. - Pathogenic bacteria reproduce rapidly inside the body and may produce poisons (toxins) which make us feel ill. |
| Viruses | - Viruses are much smaller than bacteria. - All viruses are pathogens. - Viruses produce toxins and they damage the cells in which they reproduce, leading to illness. |
| How do viruses work? What does this cause? Example? | - Viruses replicate by invading cells, reproducing inside them and bursting them. - This causes damage to tissues, leading to illness. - Example: HIV virus damages white blood cells, reducing immunity and leading to AIDS. |
| When does disease occur? | Disease occurs when large numbers of pathogenic micro-organisms enter the body. |
| Disease transmission Give 3 examples | Diseases are transmitted through: 1) Unhygienic conditions 2) Direct contact with infected people 3) Inhaling droplets from coughs or sneezes. |
| Preventing transmission -Ignaz Emmelweiss | -In the 1850s, Ignaz Emmelweiss insisted that medical students washed their hands before delivering babies. - This idea was not accepted – people were not aware of microorganisms. - people now have to wash hands after treating patients, to prevent disease being transmitted to other patients. |
| Medicines What are they used for? Give examples | - Some medicines, including painkillers, help to relieve the symptoms of infectious disease, but DO NOT kill the pathogens. - E.g. painkillers, hayfever drugs, asthma inhalers. |
| Antibiotics | -Antibiotics are substances that are used to cure bacterial infections by killing pathogenic bacteria inside the body. -Antibiotics cannot be used to kill viral pathogens This is because viruses live and reproduce inside cells. |
| Give example of an antibiotic | - Penicillin is one example of an antibiotic. Other antibiotics include tetracycline and ampicillin. |
| Antibiotics are only useful if they... | ... attack the bacteria and not the human body. |
| Immunisation | Where people can be immunised against a disease by introducing small quantities of dead or inactive forms of the pathogen into the body (vaccination). |
| How do vaccines work? | Vaccines stimulate the white blood cells to produce antibodies that destroy the pathogens. This makes the person immune to future infections by the microorganism. |
| Example of vaccine | An example is the MMR vaccine used to protect children against measles, mumps and rubella: |
| LEARN THIS | Bacteria and viruses may reproduce rapidly inside the body and may produce poisons (toxins) which make us feel ill. Viruses damage cells in which they reproduce. |
| WHITE BLOOD CELLS | :D |
| What can white blood cells do (Give three points) | -Ingest pathogens and destroy them - Produce antibodies to destroy particular pathogens -Produce antitoxins that counteract the toxins released by pathogens. |
| Key points about white blood cells | - The pathogens are not the disease - they cause the disease - White blood cells do not eat the pathogens - they ingest them -Antibodies and antitoxins are not living things - they are specialised proteins. |
| Vaccination | Vaccination involves putting a small amount of an inactive form of a pathogen, or dead pathogen, into the body. |
| What can vaccines contain? | -Live pathogens treated to make them harmless - Harmless fragments of the pathogen dead pathogens. |
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