Non-specific Body Defences Flashcards Preview

Higher Human Biology - Unit 3 > Non-specific Body Defences > Flashcards

Flashcards in Non-specific Body Defences Deck (4)
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1

What is a physical defence?

Closely packed epithelial cells found on the surface of skin and lining the body's digestive and respiratory system offer a physical barrier against bacteria and viruses

2

What is a chemical defence?

Secretions including tears, saliva, mucus and stomach acid are produced against invading pathogens (disease causing microorganism)

3

An inflammatory response is caused by what?

By a physical injury such as a cut or invasion of microorganisms

Following injury, mast cells found in the connective tissue become activated releasing large quantitates of histamine, a chemical which causes vasodilation and capillaries to become more permeable

The increased blood flow leads to accumulation of phagocytes and clotting elements at the site of infection

4

What do phagocytes do?

They recognize pathogens, engulf them and destroy them using digestive enzymes contained in lysosomes through phagocytosis

They also release cytokines (protein molecules which act as a signal) attracting more phagocytes to area of infection