non-specific defences against pathogens

How does the skin prevent the entry or pathogens?

Covers the body, has a skin flora of healthy microorganisms that outcompete pathogens for space on the body surface. Also produces sebum, an oily substance that inhibits the growth of pathogens

What are the airways lined with?

Mucous membranes that secrete sticky mucus

What do mucous membranes do?

Trap microrganisms and contais lysozymes, which destroy bacterial and fungal cell walls

What does mucus contain?

Phagocytes which remove pathogens

Where are lysozomes and what do they do?

Tears, urine, stomach acid, help to prevent pathogens getting in

What are explusive reflexes?

Coughing and sneezing, they expel pathogen mucus from the gas exchange system

What is thromboplastin in platelets?

An enzyme triggers a cascade of reactions resulting in the formation of a blood clot

What is serotonin in platelets?

Makes smooth muscles in the walls of the blood vessels contract, so they narrow and reduce the supply of blood to the area

What happens after a scab forms?

Epidermal cells below the scab start to grow sealing the wound while damaged blood vessels regrow. Collagen fibres are deposited to give the new tissue strength

What does thrombin catalyse?

soluble plasma protein fibrinogen into insoluble fibrin, fibrin forms a network of fibres that traps platelets and blood cells, forming a scab