Alcohol
• Excessive Alcohol Consumption
• Wines, beers and spirits contain an alcohol called ethanol
• It is a depressant drug - it slows down signals in the nerves and brain
• Because alcohol increases reaction times (meaning it increases the time
taken to react to situations because it slows down signalling in the brain),
there are legal limits for drinking and driving in many countries
• The liver removes alcohol from the bloodstream
• it has enzymes that break down alcohol but the products of the reactions
involved are toxic and over time, the liver can be irreparably damaged
• In many people, alcohol can be a very addictive drug
Effects of alcohol
Short-term effects of alcohol abuse Long-term effects of alcohol abuse
Vomiting: alcohol is highly toxic and this is the Damages the brain, causing memory loss and
quickest way to get rid of it confusion
Impaired judgment and potentially violent behaviour Heavy alcohol abuse over a long period of time
The user has reduced self-control damages the liver, causing cirrhosis.
Impaired balance and muscle control Social isolation, loss of friends, alienation of family
etc
Sleepiness and, when consumed in large enough
quantities, unconsciousness
Alcohol is a depressant; it slows reaction times
Effects of Tobacco Smoke
• Smoking causes chronic obstructive lung disease, coronary heart
disease and increased risks of several different types of cancer,
including lung cancer
• Chemicals in cigarettes include:
• Tar - a carcinogen (a substance that causes cancer))
• Nicotine - an addictive substance which also narrows blood vessels
• Carbon monoxide - reduces the oxygen-carrying capacity of the blood
Tar
• Tar is a carcinogen and is linked to increased chances of cancerous cells
developing in the lungs
• Tar also contributes to COPD, which occurs when chronic
bronchitis and emphysema, two different diseases which are frequently
linked to smoking, occur together
• Chronic bronchitis is caused by tar which stimulates goblet cells and mucus
glands to enlarge, producing more mucus
• Tar destroys cilia, inhibiting the cleaning of the airways,
and mucus (containing dirt, bacteria and viruses) builds up blocking the
smallest bronchioles
• A smoker's cough is an attempt to move the mucus but it damages the
epithelia resulting in scar tissue
• The scar tissue narrows the airways and makes breathing difficult
Emphysema
• Emphysema develops as a result of frequent infection,
meaning phagocytes are attracted to the lungs where they
release elastase - an enzyme that breaks down the elastin in the alveoli
walls, to enable them to reach the surface where the bacteria are
• Without adequate elastin, the alveoli cannot stretch, so they recoil and
many burst
• The breakdown of alveoli results in the appearance of large air
spaces, reducing the surface area for gas exchange and making sufferers
breathe more rapidly
• As it progresses, patients become breathless and wheezy - they may need
a constant supply of oxygen to stay alive
Carbon monoxide
• Carbon monoxide binds irreversibly to haemoglobin, reducing the
capacity of blood to carry oxygen
• This puts more strain on the breathing system as breathing frequency
and depth need to increase in order to get the same amount of
oxygen into the blood
• It also puts more strain on the circulatory system to pump the blood
faster around the body and increases the risk of coronary heart
disease and strokes
Nicotine
• Nicotine narrows blood vessels so puts more strain on the circulatory system and increases
blood pressure
• Narrow blood vessels are more likely to become clogged with fat, including cholesterol - if this
happens in the coronary artery, this causes coronary heart disease
• This means the heart muscle cells do not get sufficient oxygen and so less aerobic respiration
takes place
• To compensate the cells respire anaerobically, producing lactic acid which cannot be removed
(due to lack of blood supply)
• This creates a low pH environment in the cells causing enzymes to denature and eventually, heart
muscle cells will die
• If enough die this can cause a heart attack
• Another effect of nicotine is low birth weight in babies born to mothers who smoke during their
pregnancy
• Nicotine narrows the blood vessels in the umbilical cord, which reduces the supply of oxygen and
important food molecules to the fetus
• The placenta can also separate from the uterus, causing bleeding, premature birth and sometimes,
miscarriage or stillbirth
Smoking & Lung Cancer: Is There a Link
• The majority of cases of lung cancer are caused by smoking
• Note that as the general trend shows that as the numbers of adults who smoke
decreases, so does the lung cancer rates a few years later (as cancer takes some
time to develop)
• The trend in the rate of developing lung cancer for women has been increasing,
while in men it is decreasing
• This is because numbers of female smokers – unlike men – continued to increase
in the 1950s and 1960s before starting to fall
• As cancer takes some years to develop, a fall in female rates of lung cancer is
likely to occur later.
• Many women were exposed to secondhand smoke at home or in the workplace.
That exposure has long-term effects and contributes to non-smoking-related lung
cancer cases
• A growing percentage of lung cancers in women now occur in those who have
never smoked. This trend is particularly noted in adenocarcinoma, a type of lung
cancer more common among non-smokers and women. Genetic susceptibility
and environmental factors are still being investigated
