In this chapter of I/GCSE Biology, we will discuss about smoking.
The effects of smoking
Any effect which reduces the rate of gas exchange will reduce the concentration of oxygen available to the cells and increase the level of carbon dioxide in the blood. The body’s response to this is to increase the breathing rate and the speed at which the blood circulates (i.e. by raising heart rate and therefore blood pressure). High blood pressure can damage fragile capillaries, particularly in the brain, causing STROKE.
Cigarette smoke contains:
Tar
- Tar coats the inside of the alveoli
- Refer to I/GCSE Biology, tar is carcinogenic
- Overproduction of mucus from goblet cells and paralysis of cilia
Problems caused:
- Reduces the surface area available for gas exchange
- Cancers of the mouth, throat and lungs. 90% of all lung cancer is caused by smoking
- Extra mucus produced moves into the bronchioles and alveoli, carrying bacteria and dust with it. It blocks them. This causes extreme coughing which can lead to small tears in the alveoli which allow bacteria to enter. This can cause BRONCHITIS
Carbon monoxide
When it comes to I/GCSE Biology, it binds irreversibly with haemoglobin in red blood cells.
Problems caused:
Less oxygen is carried by the blood.
Nicotine
- Raises heart rate and causes some vasoconstriction (narrowing of blood vessels)
- Causes cholesterol to be laid down on artery walls and forms more blood clots
Problems caused:
- Increases blood pressure
- Contributes to Coronary Heart Disease and increases risk of Stroke
That's the end. Yay!
