Unit 3 Immunisation against disease

AS HSC

By the end of this session, I will be able to ....

Identify and define what is meant by the term immunisations,

Identify and define the two types of immunity,

What is immunity ?

In your group discuss the key term immunity and come up

with your own definition.

Visual introduction

http://www.youtube.com/watch?v=dWY6J2STQQ8

What is immunity ?

Immunity is the ability to resist infectious disease arising from micro organism such as fungus, bacteria and fungi,

The body produces special proteins known as antibodies which neutralise the invading pathogens and disease causing organism,

Immunisation is a term often used interchangeably with vaccination which is the process of artificially producing immunity by the use of a vaccine.

Pathogens and antigens

A bacterium or virus (a pathogen) first enters the body. Usually the skin or mucus in the nose stops it – but if you breath it in or get a cut it can get in more easily.

White blood cells (Macrophages) engulf it and notice the shape of its antigens (proteins on it’s surface which are unique to it).

The white blood cell displays the unique shape of the antigen to other cells (T helper cells) which bind to the antigen and then release chemicals which stimulate cells called B lymphocytes to reproduce rapidly.

A few B lymphocytes become memory B lymphocytes which remember the antigens shape for the future but most become antibody producing cells which are called plasma cells

Memory B cell

Antibodies

The antibodies which are produced block the pathogens ability to attack healthy body cells

The stricken pathogen may be killed in the process if its cell wall breaks down or attacked by other, usually T cells, but in the end, the whole group of cells which it is locked into, is consumed by Macrophages – very large white blood cells

http://www.dynamicscience.com.au/tester/solutions/biology/immunesystem/immunerspns1.gif

Some B cells become memory cells

Also any deactivated virus or bacteria are engulfed by Macrophages

http://www.youtube.com/watch?v=iDYL4x1Q6uU&feature=related

http://www.youtube.com/watch?v=CyxZjmgf3Pc&feature=related

Reading Task

Read through the section on pages 114 and 115 and complete the task sheet you have been given.

Make use of the dictionaries in order to find the definition to words you do not understand.

Helpful Tips

Write 5 top tips or golden rules about the topic for students taking the lesson next year.

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