MICROBIOLOGY AND INMUNITY.
• Handy definitions.
Microbe (com.name)/microorganisms organisms that you can see with a microscope.
Pathogen is a microbe that causes disease.
Immunity the ability to stop getting ill/infected.
Lymph defensive fluid.
Commensal bacteria bacteria that that live inside/on you and don’t cause you any harm.
Pathogenic bacteria bacteria that DO cause harm.
Virus not alive; can cause disease.
Pathogen microorganism that causes disease (including viruses).
1. The immune system and non-specific defences.
The immune system can be characterised as being made up of
different lines of defence. The first two lines are non-specific; the
third one is specific.
1.1. The first line of defence.
The first line of defence of the immune system is a collection of defences. They
prevent pathogens from entering the body or persisting in/on it.
1.2. The second line of defence.
The second line of defence consists of blood clotting, inflammation, wound repair and
phagocytosis.
1.1. Blood Clotting.
•What are 4 things needed for clotting to occur?
Platelets, clotting factors, fibrin and other cells (red, white cells)
•What are the 4 stages in the clotting process?
Firstly, the nearby platelets become sticky and stick together to create a plug.
Secondly, clotting factors add themselves to the plug to make it stronger. Thirdly,
fibrin acts as glue, holding everything together. Finally, other cells usually get caught
in the glue making the clot stronger.
