Non-specific human defences systems against disease

• Pathogens are disease-causing viruses, bacteria, fungi or protists, which can infect animals and plants.
• Humans have an immune system, which can defend them from pathogens.
• The immune system in defence against disease includes the first line of defence, which stops the pathogens from entering the body.
• The first lines of defence are general defences, and are not specific to fight against certain types of pathogen.
• The first lines of defence are called non-specific, and can be physical or chemical barriers.
• The skin covers almost all parts of the body to prevent infection from pathogens.
• If the skin is cut or grazed, it begins to heal itself, often by forming a scab, which prevents infection as the skin acts as a physical barrier.
• Parts of the body that do not have skin have developed other ways to prevent infection.
• The eyes produce tears, which contain enzymes, and these are chemical barriers.
• The nose has internal hairs, which act as a physical barrier to infection.
• Cells in the nose produce mucus, a slimy white protein, which lines the respiratory tract and alimentary canal.
• Mucus traps pathogens before they can enter the lungs.
• When the nose is blown, mucus is removed and any pathogens are trapped within it.
• Monoclonal antibodies are a topic in AQA Higher Biology.
• Plant disease is a topic in AQA Biology.
• The production of mucus in your airways is a physical barrier.
• Goblet cells are cells in the lining of the airways that produce mucus to trap dust and pathogens.
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• The bronchi run from the nose towards the lungs.
• Sample exam questions on infection and response are available from AQA.
• Stomach acid is a chemical barrier against infection.
• The trachea is the windpipe, the tube that leads from the mouth towards the lungs.
• The stomach is a muscular organ in the digestive system that produces hydrochloric acid and protease enzymes.
• The immune system is in defence against disease.
• Ciliated cells are cells with tiny hair-like structures on their surface, and are said to be ciliated.
• Stomach acid is part of the body's non-specific first line of defence.
• Stomach acid is strong enough to kill any pathogens that have been caught in mucus in the airways or consumed in food or water.
• Treating, curing and preventing disease is a topic in AQA Biology.
• Interpreting information from graphs is a skill in data analysis.
• Ciliated cells waft their hairs and move mucus and pathogens upwards towards the throat where it is swallowed into the stomach.