What are pathogens?
Pathogens are organisms that cause disease.
Name the types of pathogen and diseases they cause.
There are 4 types of pathogens:
1) fungi-e.g. athletes foot is caused by a fungi.
2) bacteria-e.g. cholera is caused by a bacteria.
3) viruses- e.g. flu is caused by a virus
4) protozoa (single-celled organism)-e.g. dysentery is caused by a protozoa.
What are the symptoms of an infectious disease caused by?
- cell damage
- or by the toxins produced by the pathogen.
What are mosquitoes?
Mosquitoes are vectors
What are vectors?
Vectors can carry disease without getting it themselves
What is malaria?
Malaria is caused by a protozoan, the protozoan is a parasite. It is carried by mosquitoes.
What are hosts?
Hosts are what organisms that are lived off from by other organisms.
What are parasites?
Parasites are organisms that live off other organisms and often cause it harm.
How do people get malaria?
People get malaria when mosquitoes, who have picked up the malaria parasite when they feed on an infected animal. When the mosquitoes feeds on them it inserts the parasite into their blood vessels.
How can we target mosquitoes to reduce malaria?
- Draining or spraying insecticides in the areas of water where mosquitoes lay their eggs.
- Fish can be introduced into the water to eat the mosquito larvae.
- People can be protected from mosquitoes using insecticides and mosquito nets.
How do white blood cells protect our body?
- Consuming pathogens (engulf and digest foreign cells)
- Producing antitoxins (counter the effects of any poisons produced by invading pathogens)
- Producing antibodies.
How do antibodies fight pathogens?
- antigens are the unique molecules on the surface of every pathogen.
- when a white blood cells discovers a foreign antigen they produce proteins called antibodies, which lock on to and kill invading cells. The antibodies are specific to that pathogen.
- antibodies are then produced rapidly.
- some white blood cells stay in the blood after this (memory cells). If the person is infected by the same pathogen again these cells will remember it and immediately make antibodies to kill it (naturally immune to that pathogen|).
How does immunisation work?
- dead or inactive pargogens are injected which carry antigens
- antigens trigger immune response
- memory cells remain, so next time antibodies will be produced immediately.
What is active immunity?
- immune system makes its own antibodies after being stimulated by a pathogen
- includes becoming naturally immune or artificially immune (immunisation).
- usually permanent.
What is passive immunity?
- using the antibodies made by another organism
- e.g. antibodies passed through breast feeding.
- only temorary
What are the benefits of immunisation?
- immune
- hinders the spread of disease
What are the risks of immunisation?
- short time side effects, e.g. swelling, redness at the site of injection, feeling sick for a couple of weeks after
- some think immunisation can cause other disorders, e.g. one study suggested linked between the MMR vaccine and autism.
What are antibiotics?
Drugs that kill bacteria without killing our own body cells.
What are antivirals?
Drugs that stop viruses from reproducing.
Why are some bacteria developing a resistant strain?
- misuse of antibiotics (e.g. overprescribing by doctors, patients not finishing courses) has increased the rate of development of resistant stains.
- MRSA is an antibiotic-resistant strain.
How does our body protect us from disease:
- skin provides barrier
- blood clotting prevents entry of pathogens
- pathogens are trapped by mucus in airways
- hydrochloric acid in the stomach kills pathogens
