1. Unit 4 - Immunology and Public Health

2. 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

3. 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.

4. 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

5. 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

6. 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

7. Entry Points For Pathogens
eyes
ears
nose
mouth
skin
genitals
cuts

8. 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.

9. 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

10. Chemicals barriers in the skin

11. 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

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