Health

Drugs are substances that change a person’s mental or physical state.

Depressants are drugs that lower neurotransmission levels. An example is alcohol. Stimulants increase the activity of the brain and the spinal cord. An example is cocaine.

Nicotine – an addictive drug that affects the central nervous system. It increases the heart rate and narrows the arteries, causing high blood pressure. Tar – a brown, sticky substance that consists of tiny particles and is formed when tobacco smoke condenses. Tar paralyses tiny hairs in the airways called cilia; this stops them removing mucus easily. Carbon monoxide – a poisonous gas that reduces the amount of oxygen that red blood cells can carry around the body.

A balanced diet is when you have all the nutrients, water and fibre in the correct proportions.

The five nutrients are: * Carbohydrates (simple and complex) * Proteins * Fats * Minerals * Vitamins Water and fibre are technically not nutrients but are needed for a healthy diet.

Microbes are organisms that are too small to be seen with the naked eye.

The most commmon microbes are bacteria, viruses and fungi.

• They are microscopic (around 10 to 100 times smaller than bacteria) • They either have DNA or RNA but not both • They don’t grow and divide - they must use the host cell to reproduce • They are acellular - they have no cytoplasm or cellular organelles

• Rhinovirus (common cold) • Influenza (flu) • Norovirus (stomach flu)

• They are unicellular (consisting of a single cell) • They do not have a nucleus (instead, the DNA is found in the nucleoid or as a plasmid) • They have a cell wall which gives them their shape (rod, coccus or spiral) • They are microscopic

• Antibiotics are naturally occuring or synthetic organic substances which kill selective bacteria or other microorganisms. • Antiseptics are products that kill microorganisms in or on living tissue (e.g. hand sanitiser). • Disinfectants are similar are similar but are generally products that are used on inanimate (non-living) objects or surfaces.

• Skin • Mucous membranes • Tears • Earwax • Mucus • Stomach acid

• White blood cells help the body fight infection and other diseases. There are many types, including phagocytes and lymphocytes. • Phagocytes surround and kill microorganisms, ingest foreign material, and remove dead cells. • Lymphocytes include T, B, and natural killer cells. They are responsible for antibody production, direct killing of virus-infected or tumour cells and regulation of the immune response.

Personal hygiene - wash hands, brush teeth, dress wounds, etc. Exercise - at least 30 minutes per day Diet - aim for a balanced diet, stay hydrated Sleep - teenagers 8-10 hours per night, adults 7-9 hours per night