What is a pathogen
A pathogen is a microorganism that causes a disease
Examples of pathogens
Virus, bacteria, protoctist and fungi
What does transmissible disease mean?
When the disease can be transferred from one host to another
How can a disease be transmitted
- direct contact (touching)
- Air (the disease can attach to little droplets in air)
- exchange of bodily fluids (blood or saliva)
- food and water
- vectors (when an incest lands on poop and it can land on your food or skin and transfer the disease)
Describe the bodily defences we have (physical)
- skin (acts like a wall, a barrier for your organs)
- nose hairs, helps filter, out the bacteria that are breather in
- mucus
- tears, contains salt that kills the bacteria
- eyelashes, acts like a barrier for your eyes
Describe the bodily defences we have (chemical)
- Stomach acid, can destroy most bacteria that enter by food
- wind pipe, there is mucus in the wind pipe which traps bacteria that came in by air
- white blood cells
-saliva
How to control the spread of the disease
- clean water supply, a lot of bacteria especially faeces can get into water by rivers and can go into reservoirs
- hygienic food preparation, people working in food shops can spread diseases if not careful or can get salmonella poisoning if the meat isn’t cooked properly
- waste disposal- flies and vermin can get into the the waste and diseases can grow
- sewage treatment-
What is an antigen
An antigen is a molecule that is on the outside of a pathogen. Every antigen is unique to the pathogen
The cells part of the antibody production
Lymphocytes- (a type of white blood cell)
phagocytes-(a type of white blood cell)
platelets- when you cut your skin they repair it by forming clots to stop pathogens getting in and
How the white blood cells kill pathogens
Phagocytes scout the area and engulf any pathogens they see. They warn the lymphocytes and the lymphocytes start creating antibodies The antibodies are fit together with the antigens like a key and lock this helps immobilise the pathogens. The lymphocytes create memory cells so next time the same disease comes the white blood cells are ready to fight
What is a vaccine and how do they work
A vaccine is a dead or weakened disease injected in you so the lymphocytes create the antibodies to fight the weakened disease and create memory cells
Active immunity meaning
Active-immunity when a person is infected by a disease causing the white blood cells to fight back and make memory cells this an be through a vaccine which as a dead or weakened version of the virus
Passive immunity
Passive immunity- immunity which is given to a person through a vaccination of ready made antibodies
