The human body has specialised organs such as the intestines, lungs and kidneys all have the function of exchanging materials such as digested food, oxygen, and waste. However, without the cardiovascular system also called the circulatory system, these organs could not function. The purpose of the cardiovascular system is to deliver vital materials to all cells of the body, and then take away their waste, through a network of tubes filled with fluid. The extensiveness of the cardiovascular system is that every living cell is only a few micrometres from a capillary. Blood passing by provides the cell with the material it needs and takes away its waste. The capillaries are not able to take away all the excess water that the blood carries, therefore the lymphatic system carries excess water back into the circulation system through veins near the heart. The three components of the cardiovascular system are blood – which flows in the system, carrying materials around the body. A system of vessels – arteries, veins, and capillaries –, which carry the fluid and a pump – the heart – which moves the fluid through the vessels.
During every heartbeat humans have, the heart does a double circulation: the pulmonary circulation carries blood between the heart and the lungs and the systemic circulation carries blood between the heart and the rest of the body. In a double circulation, the right side of the heart receives deoxygenated blood from the body, pumping it into the lungs. Here, the blood loses pressure. However, the blood returns to the heart, giving it a boost so that it can reach all the body parts quickly, (Boyle 2002)
The hearts structure is mainly cardiac muscle – specialised tissue that contracts automatically, powerfully and without tiring. The thickness of the walls in the heart chambers reflects on their function. The atria are thinly muscled: they pump blood the shortest distance to the ventricles directly below them. The right ventricle is more heavily muscled than either of the atria: it has to force blood a further distance to the lungs. The left ventricle has the thickest wall: it has to push blood all around the body, (see appendix 2) for this process.
The effects of smoking can have serious consequences to the structure and function of the cardio-respiratory system. People suffer with terrible illnesses such as, cardio-vascular disease – this is the main cause of death due to smoking. The hardening of the arteries is a process that develops over years when cholesterol and other fats deposit in the arteries leaving them narrow, blocked, or rigid. When the arteries narrow (atherosclerosis), blood clots are likely to form.
Smoking accelerates the hardening and narrowing process in the arteries: it starts earlier and blood clots are two to four times more likely.
Cardiovascular disease can take many forms depending on which blood vessels are involved, and all of them are more common in people who smoke. Coronary thrombosis: is a blood clot in the arteries supplying the heart, which can lead to a heart attack. Cerebral thrombosis: the vessels to the brain can become blocked, which can lead to collapse, stroke, and paralysis. If the kidney arteries are affected then high blood pressure or kidney failure results. Blockage to the vascular supply to the legs may lead to gangrene and amputation.
Smokers tend to develop coronary thrombosis 10 years earlier than non-smokers, and make up 9 out of 10 heart bypass patients.
Smokers are more likely to get cancer than non-smokers are. This is particularly true of lung cancer, throat cancer, and mouth cancer, which hardly ever affect non-smokers. The cells of all living organisms normally divide and grow in a controlled manner. Cancer results when this control process is lost. A lump or tumour, known as the primary tumour can grow locally or spread to produce secondary tumours somewhere else in the body. This spreading process is known as metastasis. (Netdoctor 2007)
Chronic obstructive pulmonary disease (COPD) is a collective term for a group of conditions that block air flow and make breathing more difficult, such as emphysema – breathlessness caused by damage to the alveoli in the lungs and chronic bronchitis – coughing with a lot of mucus that continues for at least three months.
In smokers, the rate of decline in lung function can be three times the usual rate. As lung function declines, breathlessness begins.
Chronic bronchitis is a chronic inflammatory condition in the lungs that causes the respiratory passages to be swollen and irritated increases the mucus production and may damage the lungs. The symptoms are coughing and breathlessness, which will get worse over the years. (Netdoctor 2007)
The structure of the lungs changes during a smoker’s life, if the smoker suffers from emphysema the alveoli in the lungs become damaged as they become permanently enlarged due to the destruction of the walls between the small alveoli. The destruction of the alveoli walls with their elastic fibres makes the lungs stiffer or less elastic and makes it more difficult to breathe. The loss of elasticity leads to the collapse of the air passages (bronchioles), so that air cannot move out properly and the air tends to be trapped in the lungs. The reduced expansion of the lungs during the next breath reduces the amount of air that is inhaled. As a result, less air for the exchange of gases gets into the lungs, (medicalnewstoday 2007) (See appendix 3 for lung with emphysema)
If the smoker suffers from chronic bronchitis, the bronchial tubes are irritated. Over a long period of time excessive mucus is constantly produced, the lining of the bronchial tubes becomes thickened, an irritating cough develops, air flow is hampered, and the lungs are endangered. The bronchial tubes then make the ideal breeding place for infections, (medicalnewstoday 2007) (See appendix 4 for lungs with chronic bronchitis.)
Plenty of studies show that smoking does seriously affect health. Smoking is the most common cause of COPD and is responsible for 80 per cent of cases. It is estimated that 94 per cent of 20 a-day smokers have some emphysema when the lungs are examined after death, while more than 90 per cent of non-smokers have little or none. (Netdoctor 2007)
Looking at the above statistics it is clear to see that smoking does have serious consequences on health. While it was an encouraged habit in the 1950’s it is far from encouraged now, with the government banning cigarette smoking in all public places and health warnings being constantly in the media, hoping to result in the public either quitting smoking or not starting at all.
The effects of stopping smoking take effect from as little as 8 hours after the last cigarette is smoked. After 8 hours, nicotine and carbon monoxide levels in the blood are reduced by half and oxygen levels return to normal. 24 hours later and carbon monoxide is eliminated from the body. Lungs start to clear out mucus and other smoking debris. It only takes 48 hours for nicotine to leave the body, with the ability to taste and smell being greatly improved. Breathing becomes easier after 72 hours, bronchial tubes begin to relax, and energy levels increase. Between 3 – 9 months after stopping smoking, coughs, wheezing and breathing problems improve as lung function is increased by 10%. 5 years after stopping smoking and the risk of a heart attack falls to about half of that of a smoker. Finally, 10 years after stopping smoking and the risk of lung cancer falls to half of that of a smoker. The risk of a heart attack falls to the same as someone who has never smoked. (Go smoke free leaflet 2007)
