Defense Against Infectious Disease

University:
College
Course:
College Biology
Academic year:

2023
Views:

11

Pages:

1
Author:

anon

Defense against infectious disease Defense against infectious disease Firstly, here is a list of some key terms you should know: Pathogen: A disease carrying organism foreign from the body Antigen: A substance which stimulates the production of antibodies when introduced into the body Antibody: A protein produced by B lymphocytes which prevent the pathogen from multiplying and spreading Describe the process of blood clotting When our body suffers damage and blood escapes our blood vessels, a blood clot needs to be formed in order to prevent pathogens from entering. The clotting process begins with platelets in the bloodstream and the damaged tissue cells releasing clotting factors. Firstly, prothrombin is put into its active state o thrombin by the prothrombin activator released by platelets and damaged tissue cells. Thrombin then catalyzes fibrinogen into an insoluble state, turning it into fibrin. Fibrin forms a mesh that traps red blood cells, and in this way a blood clot is formed. Outline the principle of challenge and response, clonal selection and memory cells as the basis of immunity Challenge and response refers to the idea that when the body is ‘challenged’ by a pathogen, the body has a specific ‘response’ in which to counter said pathogen. Through repetition of this process for different pathogens, the body gains immunity towards a variety of diseases. This principle is one of the main reasons vaccination is considered an effective way to gain immunity Clonal selection is the process in which a specific B cell is ‘selected’ and activated by a helper T cell along with its complimentary antigen. Activation by the helper T cell causes the B cell to clone itself. The identical B cells collectively produce a large number of antibodies, destroying the invading pathogen. Memory cells are the leftover B and T cells after the pathogen is dealt with. Because they remain in the body, they can respond quickly if the same pathogen is encountered, and is this way immunity is gained by the body. Define activeand passive immunity Active immunity is when the body itself exerts energy in order to produce antibodies when the immune system has been ‘challenged’ by a pathogen. This gives long term immunity as memory cells are formed. Passive immunity is when premade antibodies produced by another organism are put into the body. An example of this would be the antibodies a baby gets through their mother’s milk. This type of immunity is only temporary, as the foreign antibodies are eventually broken down by the recipient’s own immune system.