Smoking - Carbon Monoxide (CO)
The carbon monoxide in cigarette smoke can cause heart disease. This happens because the carbon monoxide mixes with the haemoglobin in the red blood cells, which reduces their ability to carry oxygen. If the heart doesn't have enough oxygen, you can have a heart attack.
Carbon monoxide also causes a high blood pressure, as the heart has to beat faster to deliver oxygen to the rest of the body. More beats means a faster heart rate, and a faster heart rate means more contractions of the heart - therefore increasing blood pressure.
Smoking - Tar
The tar inside cigarette smoke is very harmful. It contains toxic chemicals that are carcinogens - the scientific word for "something that causes cancer", basically. The carcinogens cause mutations in the DNA, which makes cell division go out of control and begins the formation of malignant tumours.
The types of cancer that tar can cause include; lung, throat, mouth and oesophageal cancer.
Smoking - Damage to the Cilia
Smoking causes damage to the cilia, which clear the mucus from the lungs. The cilia that are damaged are located on the epithelial tissue that lines the bronchi, bronchioles and the trachea. Because the cilia are damaged, they can no longer clear the mucus, and so it attaches to the air passages and causes smoker's cough.
Smoking also causes the lungs to lose their elasticity, which results in emphysema.
Smoking - Low Birth Weight Babies
As mentioned, carbon monoxide reduces the amount of oxygen that red blood cells can carry. This is not only bad for the smoker, but, if they are pregnant, it affects the baby too. This is because the foetus is also deprived of oxygen, and this inhibits development, leading to a low birth weight baby. This gives it the potential to be unhealthy, or have a troublesome birth.
Alcohol - Being Drunk
Alcohol, if consumed in large amounts, can lead to drunkeness. This means that the person will have impaired judgement, such as being unable to judge distance and speed, will have slurred speech, blurry sight, and sleepiness that can lead to unconciousness or even coma in serious cases.
Due to impaired judgement, there are limits on how much alcohol you can consume before driving or flying. You do not need to know the exact limits, as these will be given in an exam if required.
Alcohol - Cirrhosis of the Liver
Alcohol is a poisonous substance. It is broken down by enzymes in the liver, but some of the products made are toxic. This means that excessive alcohol consumption over a long period of time will lead to cirrhosis of the liver - this is where liver cells are killed, and scar tissue forms that stops the blood from reaching the liver. If this happens, then the liver stops working, and since as the liver's job is to clean the blood, then the toxins from the alcohol stay in the blood and damage the body.
Alcohol - Other Facts You Need To Know
1. Alcohol is a depressant - therefore, it slows down brain functions
2. It makes people feel more sociable and relaxed if consumed in moderation
3. If consumed in large doses, it can make you feel sick and light-headed due to drunkeness
4. Alcohol dehydrates the body, which can damage body cells including brain cells.