Human Defence System Flashcards
Pathogen
A disease-causing micro-organism
e.g. bacteria, virus, fungi
General Defence System
Prevents the entry of pathogens into the body or destroys them when they enter
Examples of General Defence
Skin acts as a barrier to the entry of pathogens Clotting prevents the entry of pathogens when the skin damaged Sticky Mucous in the respiratory system traps pathogens Stomach acid (HCl) destroys pathogens
Complement
A set of proteins in the plasma
Activated by infection and cause bacterial cell walls to burst
Interferons
A protein produced by body cells that prevents the multiplication of viruses
Specific Defence System
Acts against one type of pathogen or antigen
Antigen
A foreign substance that stimulates the production of antibodies
Antibody
A protein produced by white blood cells in response to an antigen
B-Cells
Made and mature in bone marrow
Move to lymph nodes
Produce antibodies
T-Cells
Made in bone marrow
Mature in thymus gland in chest
4 Types
Helper T-Cells
Stimulate the production of killer T-Cells
Recognise antigens on monocytes
Killer T-Cella
Attack and destroy abnormal body cells
Suppressor T-Cells
Inhibit B-Cells and killer T-Cells
Turn off the immune response when the pathogens have been destroyed
Memory T-Cells
Stimulate B-Cells and killer T-Cells to multiply if the same antigen enters the body again
Induced Immunity
Ability to produce antibodies against specific antigens
