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Help card ...• FOLLOWING INJURY, MAST CELLS IN THE TISSUES BECOME ACTIVATED TO
PRODUCE HISTAMINE AND VARIOUS CYTOKINES, WHICH THEN TRIGGER THE START OF THE INFLAMMATORY RESPONSE.
• HISTAMINE CAUSES VASODILATION AND INCREASED PERMEABILITY OF BLOOD CAPILLARIES. THIS RESULTS IN AN INCREASED BLOOD FLOW TO THE INFECTED AREA AND ALLOWS OTHER CELLS OF THE IMMUNE SYSTEM TO REACH THE INFECTED TISSUES.
• CYTOKINES ARE SMALL SIGNALLING MOLECULES THAT ATTRACT PHAGOCYTES TO THE SITE OF INFECTION. PHAGOCYTES ARE WHITE BLOOD CELLS THAT ENGULF AND DESTROY THE BACTERIA THAT HAVE CAUSED THE INFECTION, THEY ALSO ENGULF AND DESTROY DAMAGED TISSUE CELLS.
• THE PRESENCE OF BACTERIA AT THE SITE OF INFECTION STIMULATES ANTIMICROBIAL PROTEINS KNOWN AS ‘COMPLEMENT’ TO ARRIVE AT THE SITE OF INFECTION. THE COMPLEMENT SYSTEM HELPS THE BODY TO RID ITSELF OF INFECTION BY AMPLIFYING THE IMMUNE RESPONSE.
• CLOTTING ELEMENTS ARE ALSO ATTRACTED TO THE SITE OF INFECTION, WHERE THEY ACT TO PROMOTE COAGULATION OF THE BLOOD. THIS PREVENTS THE SITE OF INFECTION FROM BLEEDING AND ALLOWS THE INFECTED AREA TO HEAL.
Glossary termsFunction
Mast cell White blood cells found in the connective tissue which contain many histamine granules
Histamine Chemical causing vasodilation and increased permeability to capillaries
Cytokine Cell signalling protein molecules which are secreted by cells
Phagocyte White blood cell which engulf and digest (due to lysosomes with digestive enzymes) pathogens
Complement Antimicrobial proteins that amplify inflammatory response
Clotting element
Cause the coagulation of infection site for healing
Non specific
immunity
Inflammatory
Non-specific Cellular
response
Physical & chemical barriers
Specific immunity
Immunological surveillance
Clonal Selection
theory
T cellsB cells
Infectious Disease
Transmission
Epidemiology
Vaccination Public Health
Immune system
diseasesDisease survival
mechanisms
Big picture
Immunological surveillance!
• A range of types of white blood cell (leukocytes) constantly circulate, monitoring the tissues.
• If tissues become damaged or invaded a variety of cells release cytokines, which recruit specific white blood cells to the site of infection or tissue damage.
• This is called immunological surveillance
• LEUKOCYTES (WHITE BLOOD CELLS) ARE THE MOST NUMEROUS CELLS OF THE IMMUNE SYSTEM.
• THEY ARE PRODUCED IN THE BONE MARROW AND USE THE BLOOD TO TRANSPORT THEMSELVES AROUND THE BODY – THEY ARE CONSTANTLY ON THE LOOKOUT FOR MICROBES, PATHOGENS, ANTIGENS ETC. LEUKOCYTES CAN LEAVE THE CIRCULATORY SYSTEM AND ENTER THE TISSUES, WHERE THEY FUNCTION.
• IF THE TISSUES BECOME DAMAGED OR INVADED, LEUKOCYTES ARE CAPABLE OF SECRETING OVER 100 DIFFERENT PROTEIN MESSENGERS KNOWN COLLECTIVELY AS CYTOKINES.
• CYTOKINES REGULATE HOST CELL GROWTH AND FUNCTION IN BOTH SPECIFIC AND NON-SPECIFIC DEFENCES.
• SECRETION OF CYTOKINES CAN TRIGGER A NUMBER OF RESPONSES.
• SOME CYTOKINES ARE CHEMOKINES (CHEMOATTRACTANTS).
• ONCE SECRETED THESE CHEMOKINES ATTRACT PHAGOCYTES (NON-SPECIFIC) AND T CELLS (SPECIFIC) TO THE SITE OF INJURY.
• THIS STIMULATES AN INFLAMMATORY RESPONSE AS WELL AS AN IMMUNE RESPONSE.