Vena is a blood vessel that carries blood to the heart. Most veins carry deoxygenated blood from the tissue back to the heart; Exceptions are pulmonary and umbilical veins, both of which carry oxygenated blood to the heart. Unlike the veins, the arteries carry blood away from the heart.
The veins are less muscular than the arteries and are often closer to the skin. There is a valve in most of the vein to prevent backflow.
Video Vein
Structure
Veins are present throughout the body as tubes that carry blood back to the heart. Veins are classified in several ways, including superficial vs deep, lung vs systemic, and vs. large. small.
- The superficial veins are closer to the surface of the body, and do not have the corresponding arteries.
- The deeper veins inside the body and have the corresponding arteries.
- The flow of perforators flows from shallow to deep veins. This is usually referred to in the lower limbs and legs.
- Communicating veins is a vein that directly connects the superficial vein to the deep veins.
- The pulmonary vein is a set of veins that deliver oxygenated blood from the lungs to the heart.
- Systemic blood vessels secrete body tissues and deliver deoxygenated blood to the heart.
Most veins are equipped with valves to prevent blood flow in the opposite direction.
The veins are translucent, so the color of the veins that arise from outside the organism's body is determined largely by the color of the venous blood, which is usually dark red due to its low oxygen content. The veins look blue because subcutaneous fat absorbs low-frequency light, allowing only long blue-energy waves to penetrate the dark veins and reflect back to the viewer. Vein colors can be affected by the characteristics of a person's skin, how much oxygen is carried in the blood, and how big and in the vessels. When the vein is dried from the blood and removed from an organism, it appears white gray.
Venous system
The largest vein in the human body is the cavae vein. These are two large blood vessels that enter the right atrium of the heart from the top and bottom. Superior vena cava carries blood from the arm and goes to the right atrium of the heart, while the inferior vena cava carries blood from the foot and stomach to the heart. Inferior vena cava is retroperitoneal and runs to the right and is approximately parallel to the abdominal aortic spine. The large veins feed on these two veins, and the smaller veins become these. Together this forms a venous system.
While the main vein holds a relatively constant position, the venous position of person to person can display quite a lot of variation.
The pulmonary vein carries relatively oxygenated blood from the lungs to the heart. Superior and inferior venae cava carry relatively deoxygenated blood from the upper and lower systemic circulation, respectively.
The portal vein system is a series of veins or venules that directly connect the two capillary beds. Examples of such systems include the hepatic portal vein and the hypophyseal portal system.
Peripheral veins carry blood from limbs and hands and feet.
Microanatomy
Microscopically, the veins have a thick outer layer made of connective tissue, called the external tunica or tunica adventitia . There is a middle layer of fine muscle band called tunica media, which, in general, is much thinner than the arteries, because the veins do not work primarily in contractile ways and are not subject to high systolic pressure, just as arteries are. The inside is lined with endothelial cells called the intima tunica. The exact location of the vein varies more from person to person than to the artery.
Maps Vein
Function
Veins function to return blood from the organ to the heart. The vein is also called a "capacitance vessel" because most of the blood volume (60%) is contained in the vein. In the systemic circulation oxygenated blood is pumped by the left ventricle through the arteries to the muscles and organs of the body, where the nutrients and the gas are exchanged for capillaries. After taking cellular waste and carbon dioxide in capillaries, blood is channeled through vessels that meet each other to form venules, which continue to coalesce and form larger veins. The oxygen-removed blood is taken by the veins into the right atrium of the heart, which transfers blood to the right ventricle, where it is then pumped through the pulmonary artery to the lungs. In the pulmonary circulation, the pulmonary vein restores oxygenated blood from the lungs to the left atrium, which empties into the left ventricle, completes the cycle of blood circulation.
The return of blood to the heart is aided by the action of the muscle pump, and by the action of the respiratory chest pump during respiration. Standing or sitting for prolonged periods may result in low venous return of the vein (vascular) vein. Fainting can occur but usually baroreceptors in the aortic sinus begin baroreflex so that angiotensin II and norepinephrine stimulate vasoconstriction and elevated heart rate to restore blood flow. Neurogenic and hypovolemic shock may also cause fainting. In these cases, the smooth muscles surrounding the blood vessels become loose and the veins fill with most of the blood in the body, keeping blood away from the brain and causing unconsciousness. Pilot jets wear pressurized clothing to help maintain their venous return and blood pressure.
Arteries are thought to carry oxygenated blood to the tissues, while veins carry deoxygenated blood back to the heart. This is true in the systemic circulation, so far larger than the two circuits of blood in the body, which transports oxygen from the heart to the tissues of the body. However, in the pulmonary circulation, the arteries carry deoxygenated blood from the heart to the lungs, and the veins return blood from the lungs to the heart. The difference between the vein and the artery is the direction of the flow (out of the heart by the artery, back to the heart for the vein), not the oxygen content. In addition, deoxygenated blood carried from the tissues back to the heart for reoxygenation in the systemic circulation still carries oxygen, albeit far less than that carried by the systemic artery or pulmonary vein.
Although most blood vessels carry blood back to the heart, there are exceptions. The portal blood vessels carry blood between the capillary beds. For example, the hepatic portal vein draws blood from the capillary bed in the gastrointestinal tract and transports it to the capillary bed in the liver. The blood is then drained in the gastrointestinal tract and the spleen, where it is taken by the hepatic vein, and the blood is taken back to the heart. Since this is an important function in mammals, hepatic portal vein damage can be dangerous. Blood clots in the hepatic portal vein may cause portal hypertension, resulting in decreased blood fluid to the liver.
Cardiac vein
The blood vessels that are deoxygenated from the heart muscle are known as the heart veins. These include large venous heart, central heart vein, small vein of the heart, the smallest vein of the heart, and the anterior heart vein. The coronary vein carries blood with bad oxygen levels, from the myocardium to the right atrium. Most coronary venous blood returns via the coronary sinus. The anatomy of the heart vein varies greatly, but is generally formed by the following veins: the heart veins that enter the coronary sinus: the large vein of the heart, the central heart vein, the small vein of the heart, the posterior vein of the left ventricle, and the Marshall vein. Heart veins that go directly to the right atrium: the veins of the anterior heart, the smallest vein of the heart (Thebesian veins).
Clinical interests
Disease
Venous insufficiency
Venous insufficiency is the most common venous system disorder, and usually manifests as spider veins or varicose veins. Several types of treatments are used, depending on the type and pattern of the particular patient's veins and on the doctor's preference. Treatment may include Endovenous Thermal Ablation using radiofrequency or laser energy, venous exfoliation, ambulatory phlebectomy, foam sclerotherapy, laser, or compression.
Pasphlebitic syndrome is a venous insufficiency that develops after deep vein thrombosis.
deep vein thrombosis
Deep venous thrombosis is a condition in which a blood clot forms in a deep vein. These are usually the leg veins, although they may also occur in the arm vessels. Immobility, active cancer, obesity, traumatic damage and congenital abnormalities that make clots more likely are all risk factors for deep vein thrombosis. Can cause affected limbs to swell, and cause pain and skin rash on it. In the worst case, deep vein thrombosis may be widespread, or parts of the clot can break and land in the lungs, called pulmonary embolism.
The decision to treat deep vein thrombosis depends on the size, the person's symptoms, and the risk factors. It usually involves anticoagulation to prevent clotting or to reduce clot size.
Portal hypertension
Portal vein is found in the stomach and carries blood to the liver. Portal hypertension is associated with cirrhosis or liver disease, or other conditions such as inhibited clots (Budd Chiari syndrome) or compression of a tuberculosis tumor or lesion. As pressure increases in the portal vein, collateral circulation develops, causing the blood vessels to look like esophageal varices.
More
Thrombophlebitis is a condition of blood vessel inflammation associated with blood clotting.
Imaging
Ultrasound, especially duplex ultrasonography, is a common way that venoms can be seen.
Vena clinical significance
Batson's vein plexus, or Batson's Plexus, travels through the inner vertebral column connecting the thoracic and pelvic veins. These veins gain their fame from the fact that they are without valves, which is believed to be the reason for certain cancer metastases.
The large saphenous vein is the most important superficial vein of the lower limb. First described by the physician Avicenna Persia, this vein gets its name from the word safina , which means "hidden". This vein is "hidden" in the fascia compartment itself in the thigh and out of the fascia just near the knee. The inability of these veins is an important cause of lower limb varices.
Thebesia vein in the myocardium of the heart is a vein without a valve that flows directly into the heart chamber. The coronary vein is all empty to the coronary sinus that empties into the right atrium.
The dural sinus sinus in the dura mater surrounding the brain receives blood from the brain and is also the entry point of cerebrospinal fluid from the absorption of arachnoid villi. The blood eventually enters the internal jugular vein.
Phlebology
Phlebology is a medical specialty devoted to the diagnosis and treatment of venous disorders. A medical specialist in phlebology is called a phlebologist. The associated image is called a phlebograph.
The American Medical Association added phlebology to a list of self-prescribed practice specializations in 2005. In 2007, the American Board of Phlebology (ABPh), later known as the American Board of Venous & Lymphatic Medicine (ABVLM), was established to raise the standards of phlebologists and the quality of their patient care by establishing certification checks, and requiring certification maintenance. Although in 2017 not a member of the Council of American Medical Specialties (ABMS), American Board of Venous & amp; Medical lymph using a certification exam based on ABMS standards.
American College of Phlebology (ACP), one of the world's largest medical communities for doctors and health professionals working in phlebology, has 2000 members. ACP encourages education and training to improve the standards of medical practitioners and the quality of patient care.
The American Venous Forum (AVF) is a medical community for doctors and dedicated health professionals dedicated to improving patient care with venous and lymphatic diseases. The majority of its members manage the entire spectrum of venous and lymphatic diseases - from varicose veins to congenital anomalies to blockage of blood vessels to chronic venous disease. Founded in 1987, AVF encourages research, clinical innovation, hands-on education, data collection and patient outreach.
History
The earliest known article in the circulatory system is found in Ebers Papyrus (16th century BC), an ancient Egyptian medical papyrus containing more than 700 prescriptions and treatments, both physical and spiritual. In papyrus, it recognizes the heart's connection to the arteries. The Egyptians thought the air entered through the mouth and into the lungs and heart. From the heart, the air travels to each member through an artery. Although the concept of the circulatory system is only partially true, it is one of the earliest reports of scientific thought.
In the 6th century BC, the knowledge of the circulation of vital fluids through the body was discovered by Ayurvedic doctors Sushruta in ancient India. He also seems to have had knowledge of arteries, described as 'channels' by Dwivedi & amp; Dwivedi (2007). Heart valves were discovered by the Hippocratean school physician around the 4th century BC. But their function was not properly understood at the time. Due to a pool of blood in the blood vessels after death, the arteries look empty. Ancient anatomists assume that they are filled with air and that they are to transport the air.
The Greek physician, Herophilus, distinguishes blood vessels from the arteries but thinks that the pulse is the property of the artery itself. The Greek anatomist, Erasistratus, observed that the arteries were cut during the bloody period. He attributes the fact to the phenomenon that the air coming out of the arteries is replaced by the incoming blood by a very small vein between the veins and the arteries. Thus it appears to be postulated capillary but with reverse blood flow.
In the 2nd century M Rome, Greek physician Galen knew that blood vessels carry blood and identify venous blood (dark red) and arteries (brighter and thinner), each with a separate and distinct function. Growth and energy come from the venous blood that forms in the liver of chyle, while arterial blood gives vitality by containing pneuma (air) and comes from the heart. Blood flows both from creating organs to all parts of the body where it is consumed and there is no return of blood to the heart or liver. The heart does not pump blood around it, the heart's motion sucks blood during diastole and blood moves by the pulsation itself.
Galen believes that arterial blood is made by the blood of the vein that flows from the left ventricle to the right by passing through the 'pores' in the interventricular septum, air flowing from the lungs through the pulmonary artery to the left side of the heart. When arterial blood is created, "dirty" vapors are created and passed into the lungs as well through the pulmonary arteries to exhale.
In 1025, the Canon of Medicine by a Persian physician, Avicenna, "mistakenly accepted the Greek idea of ​​the existence of a hole in the ventricular septum where blood moves between the ventricles." While also refining Galen's error theory, Avicenna gives the first correct explanation of the pulse: "Each pulse consists of two movements and two pauses, so expansion: pause: contraction: pause [...] Pulse is a movement in the heart and arteries... which take the form of alternative expansion and contraction. "
In 1242, the Arabian physician, Ibn al-Nafis, became the first person to accurately describe the process of pulmonary circulation, which he had described as the Arab Circumcision . Ibn al-Nafis states in his book Anatomy Comment on Canon Avicenna :
"... the blood from the right ventricle of the heart must arrive in the left room but there is no direct path between them.The thick septum of the heart is not hollow and has no pores that look like some people think or invisible pores as thought Galen, the blood from the right ventricle must flow through the arteriolar vein (lung lung) to the lungs, spread through its substances, blend in there with air, through the arteria venosa (pulmonary vein) to reach the left chamber, vital spirit... "
In addition, Ibn al-Nafis has an insight into what would become a larger capillary circulation theory. He states that "there must be little communication or pores ( manafidh in Arabic) between the pulmonary artery and vein," predictions that precede the invention of the capillary system for more than 400 years. However, Ibn al-Nafis's theory is limited to blood transits in the lungs and does not extend throughout the body.
Michael Servetus was the first European to describe the function of pulmonary circulation, although his achievements were not widely known at the time, for several reasons. He first described it in the "Paris Manuscript" (circa 1546), but this work was never published. And then he published this description, but in a theological treatise, Christianismi Restitutio , not in a book on medicine. Only three copies of the book survived but this remained hidden for decades, the rest burned shortly after publication in 1553 due to Servetus's persecution by religious authorities.
The well-known finding of the pulmonary circulation was by Vesalius' successor in Padua, Realdo Colombo, in 1559.
Finally, William Harvey, a student of Hieronymus Fabricius (who previously described venous valves without recognizing their function), conducted a series of experiments, and published the Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus in 1628, the " indicates that there must be a direct relationship between the venous system and the arteries throughout the body, not just the lungs.Most importantly, he argues that the heart rate produces continuous blood circulation through minute connections on the extremities of the body.This is a very different conceptual leap from the consummation of Ibn al-Nafis to the anatomy and blood flow in the heart and lungs. "This work, with a truly correct exposition, is slowly convincing the medical world. However, Harvey was unable to identify the capillary system linking arteries and veins; this was later discovered by Marcello Malpighi in 1661.
In 1956, AndrÃÆ'Â © FrÃÆ'Â © ric Cournand, Werner Forssmann and Dickinson W. Richards were awarded the Nobel Prize in Medicine "for their discovery of cardiac catheterization and pathological changes in the circulatory system." In his Nobel lecture, Forssmann praised Harvey as a cardiologist with the publication of his book in 1628.
In the 1970s, Diana McSherry developed a computer-based system to create images of the circulatory and cardiac system without the need for surgery.
See also
- May-Thurner syndrome
- Nutcracker Syndrome
- Thoracic outlet syndrome
References
Further reading
- Shoja, M. M.; Tubbs, R. S.; Loukas, M.; Khalili, M.; Alakbarli, F.; Cohen-Gadol, A. A. (2009). "Vasovagal syncope in Canon of Avicenna: First mention of carotid artery hypersensitivity". International Cardiology Journal . 134 (3): 297-301. doi: 10.1016/j.ijcard.2009.02.035. PMID 19332359.
External links
- Merck article Manual on vein
- American Vein Forum
- American College of Phlebology
- American Board of Phlebology
- American College of Phlebology Foundation
- International Phlebology Association
- Australasian College of Phlebology Information from Australasian College of Phlebology Website
- In economics: Industrial arteries and veins
- Animated Vein Access Tutorial
Scientific publications
- Phlebology: The Journal of Venous Disease
- Phlebology: 1986-1999
Source of the article : Wikipedia
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