Lymphatic and Blood Vessels
Lymphatic and Blood Vessels
The vessels in the human body can be compared to a system of tubes whose role is to transport blood and lymph. These vessels can be divided into blood vessels, which include arteries, veins, and capillaries, and lymphatic vessels, which transport lymph. Arteries, veins and lymph vessels form an interconnected system that mutually cooperates.
Anatomy of Vessels
The walls of vessels is composed of three basic layers; the inner, middle and outer layers. The inner layer comes in direct contact with blood, therefore it is necessary that its surface is hydrophobic and the blood can flow smoothly. The middle layer is primarily made up of smooth muscle which tends to be thicker, especially in arteries. The outer layer connects the vessel to the surrounding tissue. These three layers vary in thickness and composition depending on the type of vessel.
Function of Blood and Lymphatic Vessels
The role of blood vessels is to transport blood from the heart to the rest of the. Blood contains oxygen and other important nutrients which must be transported to tissues and cells. This is essential for proper organ function. Blood is diverted from the heart by the largest artery called the aorta, which transports oxygenated blood. The aorta branches into smaller arteries and arterioles which connect to capillaries, where the oxygen is able to pass into the tissues and cells. The capillaries are connected to small veins, which lead to large veins, where the blood is deprived of blood and nutrients and is lead back to the heart. This circulation of blood throughout the body repeats constantly. Lymphatic vessels are responsible for the transportation of lymph, fluid emerging from tissues. These vessels are formed blindly in most organs and divert excess fluid, proteins and other substances that the tissues no longer need. The lymphatic system includes important lymph nodes that filter the lymph and remove various foreign particles found therein. All lymphatic vessels eventually combine to form two main vessels that flow into the veins, which is how lymph gets into blood. Blood vessels also ensure that the blood flowing through them does not leak or spill into the body under normal conditions. The walls of the blood vessels are able to expand and stretch in a variety of ways, therefore they can change their volume often. The most flexible are arteries, whose walls contain more muscle and connective tissue, whereas venous walls are thinner and less elastic.
Blood vessels are responsible for the transport of blood and nutrients to all tissues of the body, as well as carry away waste particles and unwanted substances the tissues do not need. If this not the case, it is a sign of a vascular disease. Vascular diseases are among the most common causes of death and can appear in men as well as women. There is a whole range of these diseases, which is why only the most common and most serious will be described.
Atherosclerosis includes changes in the walls of the blood vessels, changing its lumen. It is therefore considered the cause of a number of other illnesses. Atherosclerosis develops in virtually every individual from birth; therefore it is questionable whether it can in fact be classified as a disease. If so, then it is most definitely a chronic disease where fat is collected on arterial walls. This causes narrowing of the vessel, leading to impaired blood circulation into the affected organ and in the most serious of cases, complete blockage of the artery. In this case ischemia develops, i.e. local deprivation of blood in the surrounding tissue, causing myocardial infarction (heart attack) or stroke. Atherosclerosis is diagnosed with the help of the Doppler ultrasound or x-rays. It is treated with the help of a balloon angioplasty, a surgical procedure where a catheter containing a balloon is introduced into the affected artery and blown up in order to expand the vessel. It is also possible to subsequently reinforce the vessel with metal mesh, a stein.
An aortic aneurysm is bulging that occurs most frequently in the abdominal aorta. It is caused by weakening of the walls of this strained artery. An aneurysm usually develops form atherosclerosis and appears a lot more often in men. Bulging usually does not have any symptoms but it can be discovered by simple palpation, where in the abdominal area a pulsing area can be felt. In the event that the aneurysm bursts, sever pain follows and can lead to major bleeding which is usually fatal. An aneurysm can be found with a CT or ultrasound of the abdomen. The only treatment option of an aortic aneurysm is surgery.
Aortic dissection is a tear usually in the ascending part of the aorta, creating a pocket where blood accumulates. The tear can expand along the aorta all the way to the area of its branching. The blood tends to flow back into the blood vessel, which is favourable, but in the event that the blood flows out, death of the patient follows. It is not completely certain what causes aortic dissection, but it has been discovered that most patients with aortic dissection suffer from hypertension (high blood pressure). Dissection is manifested by severe pain behind the sternum and may resemble myocardial infarction. It is therefore necessary that the two different conditions are distinguished from each other during diagnosis. Treatment is based on medication to lower blood pressure, and surgical reparation of the blood vessel.
Raynaud's disease is a vascular disease typically manifested by attacks of pallor and pain in the finger tips. It is caused by constriction of the muscular layer of the blood vessels, narrowing the vessels and therefore decreasing blood flow. The cold and mental illnesses can trigger these symptoms, but the true cause of the vascular spasms themselves is not known. Young women are affected more often.
Vein, or venous, thrombosis is a condition that arises as a result of a blood clotting disorder or slowing of the blood flow in the veins. It usually affects the deep veins of the lower limbs where blood clots form in the vessel. This manifests by swelling, redness and pain. The danger of deep vein thrombosis is the possibility of the blood clot traveling into the pulmonary artery or its branches, where it can become wedged and cause pulmonary embolism. Individuals at risk for vein thrombosis are pregnant women, women taking hormonal birth control and individuals that stay seated for long periods of time.
Varicose veins, or varicosities, are coiled, elongated, weakened veins in which blood can no longer flow and therefore cause blood stasis. This leads to the formation of a thrombus (blood clot). This disease affects mostly the veins in the lower limbs. Varicosities develop from weakened veins and increased intraluminal pressure, the pressure inside a vein. Usually this is a disease affecting the elderly, though occasionally it can affect pregnant women or predisposed individuals. Effective treatment for varicose veins is surgery.