Pathogens and Disease
- Created by: Former Member
- Created on: 09-04-14 13:21
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- Disease and Immunity
- Disease
- Diseases can be infectious, or non-infectious.
- Anything that increases the chance of getting a disease is called a risk factor.
- Pathogens
- Pathogens are organisms that cause disease. There are three main pathogens.
- Virus
- All viruses are pathogens.
- Fungi
- Bacteria
- Virus
- Pathogens enter the body through three main interfaces.
- The gas exchange system.
- Cilia in the trachea waft up pathogens.
- Most pathogens get caught in the mucus lining of the trachea.
- The Skin
- Platelets in the blood clot to prevent pathogens entering the blood stream.
- The Digestive System
- Most pathogens are killed by the hydrochloric acid in the stomach.
- Pathogens not killed in the stomach will enter the blood stream through the intestinal lining.
- The gas exchange system.
- Pathogens are covered in proteins called antigens which stimulate an immune response.
- Pathogens are organisms that cause disease. There are three main pathogens.
- The Immune Response
- There are 4 main stages of the immune response.
- Phagocytosis
- A phagocyte recognises antigens on pathogens, engulfs pathogens and releases enzymes that destroy the pathogen.
- T-Cell Activation
- Phagocytes activate T-Cells. The T-cells then either activate B-cells or kill pathogens.
- B-Cell Acitvation
- B-Cells bind with pathogens and then produce more B-Cells and plasma cells.
- Plasma cells (memory cells) produce antibodies during the second immune response.
- Antibody Production
- Antibodies coat pathogens to make them easier to engulf and to prevent them from entering host cells.
- Antibodies bind to toxins released by pathogens and neutralise them.
- Phagocytosis
- There are 4 main stages of the immune response.
- Vaccines
- Vaccine contain inactive pathogens/antigens which stimulate an immune response.
- During the primary immune response, plasma cells are produced so during the secondary immune response antibodies can be produced immediately before symptoms are shown.
- Herd Immunity can occur.
- If a large amount of the population are vaccinated, those who are not vaccinated are also less likely to get infected as there are less carriers of the disease.
- Antigenic Variation
- Some pathogens have antigenic variation meaning not all pathogens of the species present the same antigens.
- As antigens are used in vaccines to stimulate an immune response, pathogens with a wide amount of genetic variation are difficult to vaccinate against.
- Monoclonal Antibodies
- Monoclonal antibodies are antibodies produced form a single group of genetically identical B-cells.
- They are often used to ensure that the antibodies all have the correct variable regions to bind to the antigens of the pathogens.
- Disease
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