Immunology Worksheet A Read and fill the gaps. The principal role of the immune system is to ________ (1) the body against possible infections. The immune system has evolved over millions of years to respond and destroy any organisms _____ (2) have entered the body. The complexity of immune systems generally mirrors evolutionary history: more 'primitive' organisms have immune systems composed ____ (3) discrete, general purpose, effector cells and molecules; more 'advanced' organisms have developed organs and tissues ____ (4) a specific immune purpose. A key part of Immunology involves studying ____ (5) the many different organs, cells and molecules of the immune system work and interact ____ (6) each other. The earlier form of the immune system is known ____ (7) the 'innate' immune system, and is found in a wide range of organisms (including invertebrates and primitive vertebrates); the ____ (8) form is known as the 'adaptive' immune system and is common to higher vertebrates (including humans). Specifically: * The innate immune system includes natural barriers to infection, _____ (9) as skin and cells lining the mouth, as well as the effector cells and molecules * The adaptive immune system includes specialised cells, organs and tissues _____ (10) are responsible for reacting to a specific foreign substance B Answer these questions: 1 What is the major role of the immune system? 2 Describe the difference between the ‘primitive’ and ‘advanced’ immune systems. C Read the text again and find synonyms for the following terms: 1 distinguish, tell apart 2 develop 3 particular 4 have an effect on one another 5 an obstacle Allergy A Lead-in 1 Are you allergic to anything? 2 What kinds of allergy do you know? 3 What do you know about allergies? B Affinity diagram. Put these terms into appropriate categories. C Listen and fill the missing words. 1 An allergy is an __________ to a normally harmless substance called an allergen 2 On first _________, the inhaled allergen enters the mucous membrane lining the nasal __________, where it is taken up by the antigen-presenting cell which presents it to the T-cells. These T-cells activate the B-cells to release ____________ called IgE antibodies against the allergen. 3 These IgE antibodies sit on the ___________ of the mast cells. The mast cells have granules ______________ chemical mediators like histamine and prostaglandins etc. 4 On exposure, the allergen _______________ to the IgE antibodies present on the mast cells, cross-linking them. This results in the ________________ of histamine, prostaglandins and other mediators into the surrounding tissue. 5 These mediators cause dilation of the surrounding _________________ vessels and increase their permeability. This results in the nasal _______________, sneezing and mucous discharge of allergic rhinitis. 6 Antihistamines work by _________________ the action of histamine at its receptors and thus ________________ the body’s reaction to the allergen Grammar point – Indirect speech