Unit 3 (K5) - Non-Specific Defences Flashcards
What is a pathogen?
A bacterium, virus or other organism that can cause disease.
What is immunity?
The ability of the body to resist infection by a pathogen or destroy organism if it succeeds in invading and infecting the body.
How does a non-specific defence work?
They work against ANY type of disease-causing agent.
How does a specific defence work?
Its components work against a PARTICULAR PATHOGEN.
How do epithelial cells act as a line of defence?
Closely packed epithelial cells act as a physical barrier to protect against entry of pathogens.
How does chemical defence against pathogens work?
This is achieved through chemical secretions such as mucus, tears or saliva which help aid fight invading pathogens.
Give 3 examples of physical barriers that prevent pathogens from invading/infecting the body.
- Skin
- Respiratory System
- Digestive System
Give 3 examples of chemical defences that prevent pathogens from invading/infecting the body
- Tears/sweat
- Mucus
- Saliva
- Stomach Acid
What is the second line of defence in the body?
The inflammatory Response.
Where are mast cells found?
In connective tissue around the body.
What do mast cells contain?
Histamine.
What do mast cells do?
They contain histamine which causes the vasodilation of arterioles and capillaries to be more more permeable.
How do phagocytes destroy pathogens?
By phagocytosis.
What does phagocytosis involve?
This involves engulfing pathogens and their destruction by digestive enzymes in the lysosomes.
What do cytokines do?
They attract more phagocytes to the site of infection.
