Respiratory system

• Normal lungs are pink and elastic.
• A smoker’s lungs become dark or black because tar and fine particles are deposited in the tissue.
• The lungs lose elasticity and capacity, so the smoker has chronic shortness of breath, persistent cough, reduced ability to exercise and a higher risk of lung cancer.

• Structure and function. The alveoli are small, thin-walled and very numerous (structure) and give a large surface area for exchanging oxygen and carbon dioxide between lungs and blood (function).
• Damage to this structure damages the function.
• Emphysema.

• Sticky tar condenses on the inner walls of the alveoli, which lose their elasticity.
• As tar accumulates, the walls rupture and many small sacs turn into a few large, flabby cavities.
• The surface area available for gas exchange drops sharply, so less oxygen reaches the blood.
• The patient suffers severe, chronic difficulty in breathing.

Circulatory system (heart and blood vessels)

• Carbon monoxide

• binds with the haemoglobin of the blood much more readily than oxygen does, so the blood carries less oxygen, and the body (heart, brain and muscles) is short of oxygen.
• Nicotine raises the heart rate and blood pressure and narrows (constricts) blood vessels, which raises the risk of heart disease and atherosclerosis (fatty deposits in the arteries).

Nervous system and senses

Fertility and reproduction

• Smoking reduces fertility in men and women and increases the risk of abnormalities in the fetus.

Immune system and appearance

1. Smoking weakens immunity
2. it also causes pale skin and hair loss.

• When someone smokes, nicotine reaches the brain quickly.
• It stimulates the release of substances that give a brief feeling of well-being.
• This effect fades quickly, creating a craving for another cigarette.
• Repeated smoking leads to addiction, so the habit becomes harmful and difficult to quit.
• This is why many smokers who want to stop find it so hard.

• Worked reasoning example 1. Why does a smoker get out of breath quickly when climbing stairs?
• Carbon monoxide reduces the oxygen carried by the blood; tar damages the alveoli and cuts the surface for gas exchange.
• Muscles receive less oxygen than they need, so the person breathes hard and tires easily.

• Worked reasoning example 2. Why is the gas X (colourless, odourless, toxic) in cigarette smoke carbon monoxide, and Y (dark, sticky) tar?
• CO is toxic, colourless and odourless; tar is the dark, viscous liquid made of combustion products of sugars, proteins and fibres.