Key Area 5
(a) Physical and chemical defences
Something to Read...
Open the document below and read the mandatory course notes provided by SQA for this Key Area. You may wish to use your home learning time to copy these notes into a jotter or choose a digital presentation format that suits your learning style.
Something to Watch...
Click on the white button below to access a great summary video of the immune defence system against pathogens.
Something to look at...
The first line of defence of the immune system involves physical and chemical barriers, as highlighted in the image opposite.
Epithelial cells form a physical barrier - closely-packed epithelial cells are found in the skin and inner linings of the digestive and respiratory systems.
Chemical secretions are produced against invading pathogens - Secretions include tears, saliva, mucus and stomach acid.
A pathogen is a bacterium, virus or other organism that can cause disease. Some examples of pathogens are shown in the diagram opposite.
You are now ready for your in-class lesson on chemical and physical barriers to infection.
You are now ready to move onto Key Area 5b on the inflammatory pathway.
This page was written on International Women's Day. Be strong, demand equality and be brave enough to live your biggest dreams.