Unit 4 - Immunology and Public Health

Unit 4 – Immunology and Public Health 1. The Immune System 2. Infectious Diseases and immunity Non-specific defences Specific cellular defences Transmission and control Active Immunisation and Vaccination and the evasion of immune responses

Humans have evolved well developed immune systems. We typically live in densely populated areas and come into contact with many individuals each day. Humans have evolved well developed immune systems. Particular risk of catching ‘transmitted’ diseases. To manage these hazards humans have developed public health measures and immunisation programmes Mammals have well developed immune systems. As a consequence of living in densely populated groups, humans are particularly liable to transmitted diseases. To manage these hazards humans have developed public health measures and immunisation programmes.

By the end of this section you will be able to ….. 1. The Immune System a) non-specific defences By the end of this section you will be able to ….. Name some of the body’s physical and chemical defence barriers Explain the role of epithelial cells in defence

What do you already know? In pairs, write down and discuss possible answers: What does the term ‘immunity’ mean? What does the body defend itself against on a daily basis? How does the body defend itself? Clue – think physical and chemical barriers What would happen if we didn’t have an immune system? 3 minutes

Body Defences Foreign particles such as microbes that can cause harm in your body are known as PATHOGENS We need to defend our selves against pathogens to prevent infection and disease. Our defences can be split into 2 groups: Non-specific defences Specific defences

Entry Points For Pathogens eyes ears nose mouth skin genitals cuts

Physical barriers The surface of the skin is composed of layers of closely packed epithelial cells Epithelial cells - cells that line the inner and outer surfaces of the body. Prevent pathogen entering our blood stream. Protective function.

Physical barriers The digestive and respiratory systems are lined with mucous membranes which are also composed of epithelial cells and provide a physical barrier They provide protection against pathogens as SO LONG AS THEY REMAIN IN TACT

Chemicals barriers in the skin

Non-specific defences The first non-specific defence mechanism pathogens come into contact with are the physical and chemical barriers of the body. Epithelial cells create a physical barrier between the pathogen and our blood stream Epithelial cells also produce secretions against infection, thus creating a chemical barrier. These secretions from the sweat glands and sebaceous glands contain antiseptic properties. Other physical defences include: cilia, mucus, ear wax, hairs Other chemical defences include: lysozyme in tears and saliva, hydrochloric acid in the stomach

Can you now …. Name some of the body’s physical and chemical defence barriers Explain the role of epithelial cells in defence