Scientific basis for the harm of smoking.

When smoking, 2 types of negative substances enter the human body: tar and nicotine. The harm of nicotine is that it makes the walls of arteries and veins thin and brittle. Healthy vessels have an elastic wall and respond to pressure changes by constriction and expansion. Vessels damaged by nicotine dilate poorly – a vessel rupture (stroke) may occur. The danger of resins in their ability to cause cancer, in particular cancer of the lungs, larynx, lips. At the same time, both active smoking and passive smoking are dangerous – for example, when the husband smokes, and the wife breathes.