Starter .... Complete the flow chart and glossary terms

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

Flo

w c

hart

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

Learning outcomes

• Explain immunological surveillance

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

Many white cells circulate and monitor

• 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.

Immunological surveillance

THE IMMUNE SYSTEM IS MOST LIKE .....

• NOSY PARKERS

• VIGILANTES

• NEIGHBOURHOOD WATCH

• CCTV

• BIG BROTHER

BECAUSE ......