| About 114,000 people die every year as a result
of smoking-related illnesses. All cigarettes sold now carry a prominent
health warning.
Smoking during pregnancy is very dangerous. It reduces the amount of
oxygen available to the growing foetus. This leads to an increased risk
of
- miscarriage and premature birth, and
- low weight of babies at birth.
Cigarettes contain about 4,000 different chemicals, many of which are
harmful to the body.
Nicotine
Nicotine is the addictive substance in tobacco smoke. It reaches the brain
within 20 seconds and creates a dependency so that smokers become addicted.
Carbon monoxide
Carbon monoxide combines with the haemoglobin in red blood cells and so
reduces the ability of the blood to carry oxygen. This
puts extra strain on the circulatory system, and can cause an increased
risk of heart disease and strokes.
Carcinogens
Carcinogens are substances that cause cancer. Tobacco smoke contains many
carcinogens, including tar. Smoking increases the risk of lung cancer,
mouth cancer and throat cancer.
[ This page has been adapted from www.bbc.co.uk/schools/gcsebitesize/science
] |