First 277 words of the document:
Diseases are caused by microorganisms which attack and invade the body.
Infectious diseases are spread from one person to another through unhygienic conditions or
contact with and infectious person.
Noninfectious diseases are caused by poor diet, organ malfunction, and genetic inheritance.
Pathogens are diseasecausing microorganisms. The different types are fungi, viruses,
bacteria and protozoa.
Malaria is a disease caused by a protozoan which is a parasite. Parasites live off other
animals. Mosquitoes are the vector of malaria. When the mosquito bites another person,
the malaria parasites are passed on through the blood stream where they head to the liver
where they mature and reproduce.
The body has its own way to stop pathogens getting in the body
The skin acts as a barrier
The respiratory system is lined with specialised cells that produce sticky liquid
mucus that forms a mucous membrane which traps microorganisms. Tiny hairs
called cilia move the mucus to the mouth where is swallowed
The stomach produce hydrochloric acid which kills microbes in foods
Blood clots wounds to prevent microorganisms from entering
If pathogens manage to enter the body then the bodies white blood cells start to fight them.
There are two ways the white blood cells destroy pathogens
Phagocytes move around the blood stream searching for pathogens. When they find
pathogens they engulf and digest them.
Lymphocytes produce antibodies to attack pathogens. They recognise markers called
antigens on the surface of the pathogen and produce antibodies which lock into the antigens
and kill the pathogens.
Other pages in this set
Here's a taster:
Active immunity provides immunity to someone by giving them
A weakened or dead strain of the pathogen which is incapable of multiplying
A modified pathogen which means white blood cells are produced even though the
pathogen is harmless
The positive points of immunity are that it produces against disease which could effect the
person and if everyone is vaccinated the disease will eventually die out.
The negative aspect of immunisation is that an individual could have a bad reaction to it.…read more