Disease and Immunity Flashcards
What is a pathogen?
A disease causing organism.
What is a transmissible disease?
A disease which can be passed onto one host to another.
What are the two ways that a pathogen of a transmissible disease may be transmitted to one host to another?
Direct contact ( e.g. blood or bodily fluids ) and indirect contact ( e.g. contaminated foods/ surfaces or animals. )
What are the two barriers of the bodys natural body defences and give some examples?
Mechanical barriers:
1. nostrils contain hairs that help trap dust.
2. the skin has a layer of dead skin cells.
Chemical barriers:
1. sticky mucus which can trap pathogens.
2. In the stomach, hydrochloric acid is present, which kills many of the bacteria present in the food.
If pathogens manage to get passed these barriers, how does the body get rid of the pathogens?
Pathogens that manage to get passed these barriers are destroyed by white blood cells. They take in the pathogens and digest them by phagocytosis, others produce anti-bodies that incapacitate or kill the pathogens.
What does a vaccine do?
A vaccination against a disease help anti-bodies to be made very quickly.
What are some ways of controlling the spread of diseases?
- A clean water supply
- hygienic food preparation.
- Waste disposal
- good personal hygiene
- sewage treatment.
What are the two types of immunity?
Passive and active immunity
What are anti-bodies?
Proteins that bind to the anti-gens of the pathogens leading to the destruction of the pathogen or marking them for destruction by phagocytosis.
Explain the process of destroying a pathogen?
To destroy a pathogen, anti-body molecule must be made that are exactly the right shape to fit into molecules (anti-gens) outside the pathogen.
Anti-bodies lock onto anti-gens, leading to the destruction of pathogens or marking of pathogens for phagocytes to engulf.
How is active immunity gained?
If a pathogen enters the body, it meets many lymphocytes. One of them will recognize the pathogen and divide rapidly by mitosis.
The lymophocytes then secrete anti-bodies, creating active immunity.
What is active immuntiy?
Defense against a pathogen by anti-body production in the body.
When is active immunity gained?
Active immunity is gained after an infection by a pathogen or vaccination.
Why are vaccines important to children?
Vaccines immunize children against diseases by pathogen.
In steps, explain the process of vaccination.
- weakened pathogens or antigens are put in the body
- The anti-gens simulate an immune response by lymphocytes which produces anti-bodies.
- Memory cells are produced that give long term immunity.
