Immunity & the Immune System

Discover how your body fights invaders! Learn about immunity, defense lines, and types of immune responses.

How can your body defend itself? mechanical barriers skin and hairs in the nose chemical barriers mucus and stomach acid defence cells (phagocytes) phagocytosis defence cells (lymphocytes) can be enhanced by vaccination defence cells (B-lymphocytes) antibody production by white blood cells (WBCs) Define what an antigen is. Select an image from the internet to illustrate your definition. Define what an antibody is. Select an image from the internet to illustrate your definition. Define what active immunity is. Select an image from the internet to illustrate your definition. Define what passive immunity is. Select an image from the internet to illustrate your definition. How can your body defend itself? Sort out the statements below the into the appropriate line of body defence against invaders, classifying them as 1st, 2nd or 3rd line of defence. 1st line of defence The skin provides formidable physical barrier to pathogens Healthy skin is rarely penetrated by pathogens Chemical secretions produced by skin inhibit growth of some bacteria and fungi Tears, mucus and saliva help to wash pathogens away 2nd line of defence White blood cells produce toxic (antimicrobial) substances against certain pathogens Phagocytosis performed by a type of WBC (phagocytes) Histamine promotes inflammation and fever (body temperature goes from 37 ºC up to 40 ºC) 3rd line of defence Pathogen is specifically identified by the immune system Defence carried out by specialised lymphocytes B-lymphocytes produce specific antibodies against pathogen's antigens T-lymphocytes coordinate cell-mediated immunity Types of immunity Sort out the statements below the into the appropriate type of immunity: specific (acquired immunity) or non-specific (innate immunity). Innate immunity (non-specific) skin and hairs in the nose tears, mucus, saliva mucus and stomach acid phagocytosis Acquired immunity (specific) antibody production by a type of white blood cells antibody transfer from mother to foetus via placenta breastmilk is rich in antibodies vaccines introduce attenuated antigens into the body immune serum contains antibodies against antigens Types of acquired immunity Match the statements on the left with the appropriate type of acquired immunity: naturally (active or passive) and artificially (active or passive). antigens enter the body accidentally naturally - active antibodies pass from mother to child via placenta naturally - passive antibodies pass from mother to child via breastmilk naturally - passive antigens are introduced in the body by vaccine(s) artificially - active the body produces antibodies and specialised lymphocytes artificially (or naturally) - active antibodies are introduced in the body by immune serum articially - passive