The Circulatory System
The circulatory system is made up of vessels and muscles that help and control the flow of the blood around the body. This process is called circulation. The main parts of the system are the heart, arteries, capillaries and veins. The circulatory system does a very important job in your body. It carries oxygen and essential nutrients to all cells around the body in arteries and carries the waste products and carbon dioxide in veins. The average human body contains over 60,000 miles of blood vessels. What is an artery? Arteries are the pipes that carry blood, rich with oxygen and nutrients, away from the heart. As the blood travels round the arteries, it branches off to be able to deliver oxygen and nutrients to specific cells. The blood in your arteries is bright red and is under high pressure as the heart pumps it around the body. What is a vein? Veins are the pipes that carry deoxygenated blood and waste products around the body. As cells use the oxygen and nutrients delivered by the arteries they create waste products, such as carbon dioxide. The veins then pick up this waste and deliver it around the body for it to be disposed of and then deliver the deoxygenated blood back to the heart. The blood in your veins is under considerably less pressure than in your arteries as it is moving upward back to your heart. Veins have valves in them to stop the blood flowing backwards. What is plaque? Plaque is a build of fat, calcium, cholesterol and other waste products found in your blood. It is very sticky and sticks to the walls of your arteries. The build up of plaque takes many years and hardens as it ages. It narrows your blood vessels and makes it harder for the oxygenated blood to flow around your body and deliver nutrients to your organs. The slow build-up of plaque is caused by high blood pressure, diabetes, smoking, high blood cholesterol, and other modifiable risk factors.
The common vascular problems are caused by a slow and gradual thickening of the arteries, sometimes referred to as "furring up"; "hardening" or "clogging" up of the arteries. The technical name for this is atherosclerosis. Certain arteries become less flexible, they lose their elasticity over time. This makes them less able to withstand the pressure of the pulse generated by the heart. They can slowly stretch, like a worn out tyre / inner tube, and this leads to a dilated artery we call an aneurysm. Both these changes in our arteries are linked to certain lifestyle and medical factors which make vascular disease more likely.
Peripheral Arterial Disease (PAD) is defined as atherosclerosis occurring in arteries outside of the heart and brain. The commonest problem this caases is reduced circulation to the legs with pain in the leg muscles when walking and sometimes in the foot at rest when the circulation is very low. The prevalance of PAD increases with age and is greater in people with cardiovascular disease or diagetes than in the general population. The mortality rate in people with PAD is high - around 50% at 5 years and 70% at 10 years. Cardiovascular events (fatal and non-fata) are more likely in people with PAD. Treating PAD is therefore doubly important both to improve symptoms in the legs but also to reduce premature death and disability.
Atherosclerosis in the carotid artery of the neck can be a cause of stroke. Disease in the kidney arteries can cause kidney failure. Disease in the arteries to the bowel can lead to pain eating, weight loss, bowel damage which in severe cases can cause the bowel to die and perforate, which is a life threatening surgical emergency.
The veins in your leg are part of the circulation carrying blood up the leg towards the heart. There are two main types of veins :
Superficial : - these are the visible veins under the skin more prominent when standing up.
Deep : - these are within the muscles of the leg and cannot be seen.
The veins need to carry the blood upwards against gravity when we are standing. In order to do this they contain one - way VALVES. The muscles in the leg are also involved. During walking, which is particularly good for venous problems, the calf muscles squeeze the deep veins increasing the flow up out of the leg. This reduces the pressure in the veins. Since the deep and superficial veins are connected the benefits of this are felt in all veins of the leg. Standing still has the opposite effect, raising pressure in the veins and reducing flow.
This occurs when the superficial veins become dilated and irregular. There are several reasons for this occurring. The veins may be weak to start with, there may be a reduced number of valves or the superficial veins may be exposed to abnormally high pressures from the deep veins. Many of these factors run in families. Once "varicose" the valves in the superficial veins do not work and the flow follows gravity, down the leg when standing. This is why the pain and swelling due to varicose veins is often worse after standing or at the end of the day. Elastic support stockings compress the varicose veins and reduce the flow down them improving the circulation (NB do not use stockings if you have bad arterial disease in the legs). Elevation of the legs whenever possible and avoiding long periods of standing will also help relieve the symptoms of varicose veins. Being overweight raises the pressure in the leg veins so losing weight can also be very beneficial.
Varicose veins are very common and with the help of the above measures many people do not need invasive treatment. If symptoms are severe however the varicose veins can be treated providing the deep veins are working well. A small number of patients develop red flaky itchy skin with brown staining. If this occurs the above measures should be taken to help the venous circulation. If the problem persists then intervention ofr the varicose veins is probably indicated. In a small number of these severe cases an ulcer can form on the leg if there is no treatment at all. Again the above measures plus intervention in some cases will prevent ulcers or help ulcers that are already present to heal.
A thrombosis (clot) can form in the superficial veins and they become inflamed as a result. This is called phlebitis. The vein is red, swollen and painful. The condition usually resolves over 4 - 6 weeks. Painkillers, a supportive bandage or tubigrip may help. If it is severe and extensive seek medical advice.
If the venous system in the leg fails to work normally (see above) the pressure in the leg veins rises. This damages the circulation in the lower leg particularly around the ankle leading to swelling, discomfort, skin changes and eventually ulceration. Varicose veins, a previous DVT, or primary failure of the valves in the veins can all contribute to this. The simple measures described above (elastic stockings, walking, avoiding standing, elevation, weight control) are all very important in the management of this problem. Procedures on the veins may help, particularly if the problem is mainly in the superficial veins.