Pathogens and Immunity

Pathogens and Immunology including: Lifestyle, responce, antigens and antibodies

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  • Created by: AmaniF
  • Created on: 27-05-13 17:55
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Pathogens and Immunology
Description: A disease causing organism
Pathogens can be transmitted by droplets, - in the air - direct contact with the skin, through food
contamination, the urino-genital system and through the gas exchange system.
The body prevents entry of pathogens with a thick layer of skin, mucus, stomach acid and the immune
Overcrowded conditions enable diseases to spread rapidly.
Epidemics - Widespread outbreaks of disease
Pandemics - Epidemics that spread internationally
Viruses: Enter cells and ruptures them cause them to release nutrients. They break down nutrients in
the cell which starves the cell and they can replicate, causing the cell to burst.
Bacteria: Produce cell killing toxins. Exotoxins are proteins that are secreted by bacteria. Endotoxins
are complex compounds released by bacteria which are engulfed by macrophages and cause the
macrophages to produce proteins that alter the body's temperature-regulating mechanisms.
For a microorganism to be considered a pathogen it must gain entry to the host, colonise the tissues
of the host, resist the defences of the host and cause damage to the host tissues.
Pathogens can enter the host cell by endocytosis or by producing enzymes that breach the host cell
The period of time between infection and the appearance of the signs and symptoms of a disease is
called the incubation period.
Risk = A measure of the probability that damage to health will occur as a result of a given hazard.
Risk factors and cancer
Age and genetic factors are beyond our control
Low amounts of physical activity
Sunlight (skin cancer)
Risk factors and CHD
Age, sex and genetic factors are beyond our control
High blood pressure
Blood cholesterol levels

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Low amounts of physical activity
How do we respond to a break in our defences?
Our response is divided into two parts; Non-specific and Specific response.
Non-specific response
Physical barrier
Inflammation due to the blood vessels in the affected area becoming more permeable and
so more white blood cells and antibodies can come to the infected area.
Body temperature rises.…read more

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Antibodies coat pathogens by forming antigen-antibody so that they are easier to engulf and
prevent them from entering the host's cells. They bind with and neutralise the toxins produced from
the pathogen.
What is an antigen? Specific response
An antigen is a protein or carbohydrate on the surface of a cell which can be used for identification. It
is used in the process of specific response.
Lymphocytes deal with specific response.…read more

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Vaccinations stimulate primary response so that when the actual pathogen is encountered, the
secondary response is strong enough to prevent the disease from developing and reducing the
incubation time.…read more

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The drug accumulates in the body where there are cancer cells…read more


arianator 4 life

your resources are really good



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