The effects of smoking on bodily systems.

As described in earlier posts smoking has a significant effect on several body systems. The major systems that are affected by smoking are the respiratory systems and cardiovascular systems.
It affects the respiratory system by coating the lungs with tar causing cells to mutate into cancerous cells resulting in lung cancer.
It can make the respiratory tract (bronchi) prone to infection(bronchitis) and cause emphysema.
Smoking increases the risk of heart disease as smoking causes plaque to build up in the arteries leading to atherosclerosis or hardening of the arteries. This in turn raises blood pressure increasing the risk of heart attack and strokes. Also smokers suffer from poor circulation due to blocked arteries and in extreme circumstances can lead to amputation of limbs.
Smoking can reduce the efficiency of the immune system and make us more susceptible to other illnesses.

Smoking can be attributed to a whole number of problems with body systems and cause them to break down and not function properly. The campaign to get people to quit is well intentioned and could save the NHS millions in smoking related diseases, however smoking is a hard habit to break and it will be some time before smoking is eliminated entirely.

Smoking, coronary heart disease and lung cancer.

Smoking is directly related to coronary heart disease. The toxins in cigarette smoke cause plaques to form in the arteries which leads to atherosclerosis. Smoking also increases blood pressure, increasing the likelihood of stroke. Congestive heart failure is closely liked to atherosclerosis and smoking.

In America 61 million people suffer from a form of cardiovascular disease. 2600 die every day due to coronary heart diseases. Coronary heart disease caused by smoking is the leading cause of death in America and has been linked with sudden cardiac death in both men and women.
Smoking related coronary heart disease is thought to contribute to congestive heart failure. 4300 Americans die from this disease every year.

People who smoke are at a much higher risk than those who don't. Clearly smoking is a huge contributor, if not the main source, for coronary heart disease.

Smoking causes 9 out 0f 10 cases of lung cancer. There around 39,400 people diagnosed with lung cancer in the UK every year. It is the second most common cancer in men and third in women in the UK but is the most common type of cancer worldwide.
Smoking causes 90% of lung cancer deaths as smokers are 15 times more likely to die from lung cancer than non-smokers.
Quitting smoking has a postive reducing effect on the liklihood of developing lung cancer. This can be seen on the graph below.

The graph clearly shows then benefits of quitting smoking and the relation to lung cancer. It also highlights the connection between smoking and lung cancer.

Smoking is the primary cause of lung cancer and is responsible for the most deaths worldwide when looking at cancer. Smoking is the primary cause of lung cancer, and if it is the cause of 90% per cent of cases then by eliminating smoking you could reduce lung cancer occurance by 90%, which would almost eliminate it.

References:

www.cancerhelp.org.uk/type/lung-cancer/about/lung-cancer-risks-and-causes

http://quitsmoking.about.com/od/tabaccostatistics/a/heartdiseases.htm

http://info.cancerresearchuk.org/cancerstats/types/lung/riskfactors/index.htm

Diet, blood pressure, cholesterol and circulatory disease.

Diet, blood pressure, cholesterol and circulatory disease are all connected. A poor diet can lead to high cholesterol levels which increases the chance of circulatory disease, such as atherosclerosis.
There are two types of cholesterol: LDL which is the harmful one and HDL which is the protective one. A diet rich in saturated fat will increase the level of LDL cholesterol in the blood. This means that it is more likely that fatty deposits will develop within the arteries, leading to circulatory problems such as atherosclerosis.

Atherosclerosis results in the narrowing of the arteries, this then causes more resistance to blood flow which in turn raises blood pressure, making the individual more prone to heart attacks and strokes.

The main contributing factors to high blood pressure and high cholesterol, apart from diet, are:
Lack of exercise
Obesity
Excess alcohol
Diabetes
Gender
Age
Genes

A poor high fat diet will increase cholesterol which in turn raises blood pressure and as a result will put you at a much higher risk of suffering from circulatory disease. On the other hand a balanced low fat diet can reduce cholesterol levels and blood pressure thus, lowering the chances of suffering from circulatory disease.

References:
www.patient.co.uk/health/High-Blood-Pressure-(Hypertension).htm

www.bhf.org.uk/Keeping_your_heart_healthy/preventing_heart_disease/cholesterol.aspx

Changes in artery stucture associated with circulatory disease.

Peripheral artery disease affects the arteies that carry blood from the heart to the rest of the body. This condition causes the arteries to narrow which restricts blood flow to the limbs and muscles.

Peripheral artery disease usually affects the legs causing pain that can come on while walking.

Peripheral artery disease is caused by fatty deposits building up on the inside walls of the arteries. This is known as atherosclerosis. The fatty deposits cause arteries to narrow which restricts blood flow to tissues. This can cause pain in muscles, especially when exercising, as the muscles cant get enough blood and therefore not enough nutrients to function properly.

Atherosclerosis increases the risk of heart attack and stroke.

Other diseases that can cause change in arterial structure are called aneurysms. An aneurysm is an abnormal bulge in a blood vessel and occur most commonly in the aorta. Atherosclerosis can lead to an aneurysm and an aneurysm is more likely to be the site of fatty deposits. Most of the time aneurysms are small but sometimes, if they get big enough, they can burst which would requie immediate medical attention.

References:

http://hcd2.bupa.co.uk/fact_sheets/html/peripheral_arterial_disease.html

www.medicinenet.com/vascular_disease/article.htm

Mechanisms for regulating ventilation and pulse rates.

Ventilation rate is controlled by the medulla and the pons in the brain stem. The activity of this centre is stimulated by peripheral chemoreceptors, which are located in the aorta and carotid arteries.
Chemoreceptors are specialised nerve cells that monitor the pH of blood. They measure the pH of blood by detecting hydrogen ion concentration, the higher the concentration the more acidic the blood. Chemoreceptors also monitor carbon dioxide levels in the blood. It is carbon dioxide that influences the amount of hydrogen ions in the blood.
When levels of carbon dioxide and hydrogen ions become high the chemoreceptors stimulate the respiratory centres to speed up so that the excess carbon dioxide and hydrogen can be removed from the blood.

The pulse rate is regulated by by the sino-atrial node. This specialised group of cells are responsible for generating the electrical impulses that makes the heart contract.
Like ventilation rate pulse rate can be affected by chemoreceptors. An increased ventilation rate usually goes hand in hand with increased pulse rate. This is because the blood needs to travel faster in order to get to the lungs so that carbon dioxide can be exhaled. An increase in ventilation rate will stimulate the SA node to increase its rate of fire thus increasing the pulse rate.

References:
www.howstuffworks.com/lung3.htm

Cardiac Output

Cardiac output is the amount of blood pumped by the heart per minute and is measured in millilitres of blood per minute. In order to calculate cardiac output you have to times stroke volume (millilitres per beat) by heart rate (bpm).
The average person will have a stroke volume of about 70ml/min and a heart rate of 70bpm, cardiac output would be as follows:

70 x 70 =4,900ml of blood per minute.

This means that 4,900 ml of blood is being pushed out of the left ventricle per minute, which is equivalent to how much blood an average person has in their circulatory system. This measurement is a normal person at rest. During exercise cardiac output can increase up to 7 times.

Cardiac output is a measure of the amount of blood pumped around the body every minute. Blood carries all the essential nutrients that the body needs to function. If cardiac output is low then it could be a sign of cardiac disease, and as a result the body will not be getting the nutrients it need to function properly. This makes measuring cardiac output an important indicator of potential cardiac health problems.

References:
www.biosbcc.net/doohan/sample/htm/COandMAPhtm.htm

Electrical Activity of the heart.

The heart has a specialised natural pacemaker known as the sino-atrial (SA) node. The sino-atrial node is responsible for making the heart beat and regulating the cardiac cycle. The heart is the only organ that acts independently of the brain, the SA node generates its own nerve impulses.

The SA node is located in the upper portion of the right atrium and when it sends an impulse it sets off a chain of events.

When it first fires, the electrical impulse travels across both of the atria making them contract, this forces blood within the atria to be pushed into the ventricles.

The impulse then moves to to the atrio-ventricular (AV) node, this is located just above the ventricles. The impulse is delayed for a brief period at the AV node. This delay allows the atria to empty the blood into the ventricles.

After the delay the impulse then travels throughout he ventricles via special pathways called purkinje fibres. This then stimulates the ventricles to contract forcing the blood out and into the pulmonary artery and the aorta.

This cycle happens around 72 times per minute.

References:

www.heartsite.com/html/electrical_activity.html

http://heratdisease.about.com/od/palpitationsarrhythmias/ss/electricheart.htm