Digestive 
Blood
Cardiovascular
Dermatology
Genitourinary,
Hormones
Infections
Oncology and
Musculo-skeletal
Mental health and
Parasites
Respiratory
Senses
Various
The components of a cigarette are:
- Nicotine: responsible for most of the effects of tobacco and what causes physical dependence. The half-life of nicotine in the blood is less than two hours and, as the concentration decreases, the symptoms that awaken the desire for a cigarette appear again.
- Irritants: the substances responsible for the typical smoker’s cough and stimulate the mucus-secreting glands, which alter the lung’s defence mechanisms.
- Tars and carcinogens.
- Carbon monoxide is found in very high amounts in smoke. It has a great affinity with haemoglobin, which causes a decrease in the blood’s ability to carry oxygen.
