Smoking can causes lots of things: lung cancer, bronchitis, emphysema etc. They are also a major contributing factor to other problems such as coronary heart diseases, stomach and duodenum ulcers. Pregnant smokers are more likely to give birth to underweight babies. 🚬🚬🚬
Tar
- Tar in cigarettes destroys the cilia in airways. This means that mucus is not swept away from the lungs, but remains and clogs the air passages. This is made worse by the fact that the smoke irritates the lining of airways, stimulating cells to secrete more mucus.
- Irritation of the bronchial tree, along with infections from bacteria in the mucus can cause the bronchitis, which causes blocking in normal airflow, so the sufferer has difficulty breathing properly.
Emphysema and Lung cancer
- Emphysema is another lung disease. Smoke damages the walls of the alveoli, causing them to break down and fuse together. This greatly reduces the surface area for gas exchange. The blood of a person with emphysema carries less oxygen. There is no cure.
- Lung cancer happens when cells mutate and divide uncontrollably, forming tumours. Smoking increases the chance of this; however, giving up the habit can soon improve your chances of survival.
But what makes it so addictive?
- Cigarette smoke contains a strongly addictive drug known as nicotine, which eases stress. It also contains at least 17 chemicals that are known to cause cancer. These are called carcinogens.
- Carbon monoxide is another harmful and poisonous gas found in cigarettes. When inhaled, the gas attaches itself to a chemical that carries oxygen in the body, known as haemoglobin. When combined with carbon monoxide, it forms carboxyhaemoglobin. When this happens, the blood carries less oxygen around the body. Carbon monoxide from smoking is a major cause of heart disease.
Giving it Up!!! 🚭
Smoking is hard to give up because of the addictive nicotine.
- Nicotine is actually harmless, and the brain secretes it to ease stress. Therefore, some smokers use nicotine patches or nicotine chewing up as a source of nicotine. Gradually, the nicotine dose reduces until the smoker is weaned off the habit. Other ways include acupuncture and hypnotism.
The Smoking Machine

The smoking machine shows the effects of smoking. In I/GCSE Biology, we can ignore the labels in the diagram. The cigarette smoke would make the glass wool yellowish (thanks to the tar). The Universal Indicator would turn orange red, showing the fact that the smoke is acidic. Finally, if the tube was connected to limewater, the limewater would turn cloudy in the presence of carbon monoxide.
That's the end of the topic!

Drafted by Joey (Biology)