What problems can smoking cause?

Addiction - Nicotine is the addictive substance in tobacco. It reaches the brain within 20 seconds and creates a dependency so that smokers become addicted. Smokers can suffer from withdrawal symptoms if they try to give up cigarettes.
Heart disease - 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.
Low birth weight babies - Smoking during pregnancy is very dangerous. It reduces the amount of oxygen available to the growing fetus.
Lung, throat, mouth and oesophageal cancer - Tar from cigarettes smoke collects in lungs. It is irritant and it contains carcinogens that can mutations in DNA - causing malignant tumours.

The images below compare a healthy lung and a smoker's lung:

	Created by Carina C over 8 years ago

GCSE Biology (Module B1: Understanding Organisms) Note on B1e: Drugs and you, created by Carina C on 04/04/2016.