vein
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(vān) 
n.
n.
- Anatomy. Any of the membranous tubes that form a branching system and carry blood to the heart.
- A blood vessel.
- Botany. One of the vascular bundles or ribs that form the branching framework of conducting and supporting tissues in a leaf or other expanded plant organ. Also called nervure.
- Zoology. One of the horny ribs that stiffen and support the wing of an insect. Also called nervure.
- Geology. A regularly shaped and lengthy occurrence of an ore; a lode.
- A long wavy strip of a different shade or color, as in wood or marble, or as mold in cheese.
- A fissure, crack, or cleft.
- A pervading character or quality; a streak: "All through the interminable narrative there ran a vein of impressive earnestness" (Mark Twain). See synonyms at streak.
- A transient attitude or mood.
- A particular turn of mind: spoke later in a more serious vein.
- To supply or fill with veins.
- To mark or decorate with veins.
[Middle English veine, from Old French, from Latin vēna.]
veinal vein'al adj.
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Vessel that carries blood to the heart. Except for the pulmonary veins, veins bear deoxygenated blood from capillaries, which converge into threadlike venules and then veins, finally emptying into the venae cavae ( cardiovascular system; vena cava). Blood moves through veins by contraction of the surrounding muscles. Backflow is prevented by valves in most veins' inner layer (tunica intima), which lacks the elastic membrane lining of arteries. The thin middle layer (tunica media) is mostly collagen fibres, and the thick outer layer (tunica adventitia) is mostly connective tissue. circulation; varicose vein.
For more information on vein, visit Britannica.com.
Roget's Thesaurus:
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vein
noun
- An intermixture of a contrasting or unexpected quality, especially in a person's character: strain2, streak. See be.
- A temporary state of mind or feeling: frame of mind, humor, mood, spirit (used in plural), temper. See feelings.
- A distinctive way of expressing oneself: fashion, manner, mode, style, tone. See style/good style/bad style.
Vessel carrying blood to the heart. A vein usually has thin walls and a series of one-way valves.
Veins
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vein, blood vessel that returns blood to the heart. Except for the pulmonary vein, which carries oxygenated blood from the lungs to the heart, veins carry deoxygenated blood. The oxygen-depleted blood passes from the capillaries to the venules (small veins). The venules feed into larger veins, which eventually merge into the superior and inferior vena cavae, large vessels that consolidate the blood flow from the head, neck, and arms and from the trunk and legs, respectively (see also circulatory system). The vena cavae direct the blood back into the heart. The walls of a vein are formed of three layers like the walls of an artery. However, these layers are thinner and less muscular and collapse when empty. With such notable exceptions as the portal system, most veins contain valves, formed by pouches in their inner coats, that keep the blood from flowing backward. Valves are most numerous in the veins of the extremities, and are absent in the smallest veins. Veins are subject to inflammation, dilatation or enlargement (as in a varicose vein), rupture, and blockage by blood clots (thrombosis).
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Blood vessels that return blood from the body tissues to the heart. (Compare arteries; see circulatory system.)
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One of the vascular bundles or ribs that form the branching framework of conducting and supporting tissues in a leaf, flower, or fruit.
A more or less upright sheet deposit of minerals, cutting other rocks and formed from solutions rather than from a molten magma like a dike.
Word Tutor:
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vein
IN BRIEF: Any blood vessel that carries blood back to the heart from some part of the body. Also: A layer of mineral or rock formed in a crack in different rock.
Love is a second life; it grows into the soul, warms every vein, and beats in every pulse.
— Joseph Addison (1672-1719).
Tutor's tip: Other words that sound like vein which is a kind of blood vessel, are vain which means useless or having a high opinion of oneself and vane which is a part of a propeller .
LearnThatWord.com is a free vocabulary and spelling program where you only pay for results!
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- (in animals) the blood vessels conducting blood from the tissues.
- (in plants) a vascular bundle in a leaf.
| vehicle, vegetative reproduction, vegetative bacteriophage | |
| velocity of reaction, venom, venombin |
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A vessel through which blood passes from various organs or parts back towards the heart, in the systemic circulation carrying blood that has given up most of its oxygen. Veins, like arteries, have three coats, an inner, middle and outer, but the coats are not so thick and they collapse when the vessel is cut. Many veins, especially the superficial, have valves formed of reduplication of their lining membrane. For a complete list of the named veins of the body,
- afferent v's — veins that carry blood to an organ.
- allantoic v's — paired vessels that accompany the allantois, growing out from the primitive hindgut and entering the body stalk of the early embryo.
- cardinal v's — the major veins within the early embryo that include the pre- and postcardinal veins and the ducts of Cuvier (common cardinal veins).
- emissary v. — a vein escaping from a chamber or organ such as one passing through a foramen of the skull and draining blood from a cerebral sinus into a vessel outside the skull.
- postcardinal v's — paired vessels in the early embryo that return blood from regions caudal to the heart.
- precardinal v's — paired venous trunks in the embryo cranial to the heart.
- pulp v's — vessels draining the venous sinuses of the spleen.
- subcardinal v's — paired vessels in the embryo, replacing the postcardinal veins and persisting to some degree as definitive vessels.
- sublobular v's — tributaries of the hepatic veins that receive the central veins of hepatic lobules.
- supracardinal v's — paired vessels in the embryo developing later than the subcardinal veins and persisting chiefly as the lower segment of the inferior vena cava.
- thebesian v's — smallest cardiac veins: numerous small veins arising in the muscular walls and draining independently into the cavities of the heart, and most readily seen in the atria.
- trabecular v's — vessels coursing in splenic trabeculae, formed by tributary pulp veins.
- varicose v's — permanently dilated, tortuous veins. The milk vein of a lactating cow is a normal varicose vein. See varicose veins.
- vitelline v's — veins that return the blood from the yolk sac to the primitive heart of the early embryo.
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(vān)
n
n
A blood vessel that conducts blood from the capillary bed to the heart. Size may range from the venules to small veins to large veins.
Random House Word Menu:
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categories related to 'vein'
- Heart and Circulatory and Lymphatic Systems - vein: blood vessel conducting blood from tissue back to heart
- Processes, Phenomena, Events, and Techniques - vein: narrow water channel in rock or earth
- Mining - vein: lengthy, regularly shaped bed of useful mineral matter that fills narrow water channel in rock and earth; lode; reef
See crossword solutions for the clue
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For other uses, see Vein (disambiguation).
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This article includes a list of references, related reading or external links, but its sources remain unclear because it lacks inline citations. Please improve this article by introducing more precise citations. (June 2008) |
| Vein | |
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| The main veins in the human body | |
| Latin | vena |
In the circulatory system, veins (from the Latin vena) are blood vessels that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart. Veins differ from arteries in structure and function; for example, arteries are more muscular than veins, veins are often closer to the skin and contain valves to help keep blood flowing toward the heart, while arteries carry blood away from the heart.
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Contents
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Anatomy
In general, veins function to return deoxygenated blood to the heart, and are essentially tubes that collapse when their lumens are not filled with blood. The thick outermost layer of a vein is made of connective tissue, called tunica adventitia or tunica externa. Deeper are bands of smooth muscle called tunica media, which are, in general, thin, as veins do not function primarily in a contractile manner. The interior is lined with endothelial cells called tunica intima. The precise location of veins is much more variable from person to person than that of arteries.[1] Veins often display a lot of anatomical variation compared with arteries within a species and between species.
Notable veins and vein systems
The great saphenous vein is the most important superficial vein of the lower limb. First described by the Persian physician Avicenna, this vein derives its name from the word safina, meaning "hidden". This vein is "hidden" in its own fascial compartment in the thigh and exits the fascia only near the knee. Incompetence of this vein is an important cause of varicose veins of lower limbs.
The pulmonary veins carry relatively oxygenated blood from the lungs to the heart. The superior and inferior venae cavae carry relatively deoxygenated blood from the upper and lower systemic circulations, respectively.
A portal venous system is a series of veins or venules that directly connect two capillary beds. Examples of such systems include the hepatic portal vein and hypophyseal portal system
The Thebesian veins within the myocardium of the heart are valveless veins that drain directly into the chambers of the heart. The coronary veins all empty into the coronary sinus which empties into the right atrium.
The Dural sinuses within the dura mater surrounding the brain receive blood from the brain and also are a point of entry of cerebrospinal fluid from arachnoid villi absorption. Blood eventually enters the internal jugular vein.
Color
Vein color is determined in large part by the color of venous blood, which is usually dark red (and not blue as is commonly believed) as a result of its low oxygen content. Veins appear blue because the subcutaneous fat absorbs low-frequency light, permitting only the highly energetic blue wavelengths to penetrate through to the dark vein and reflect back to the viewer. A recent study found the color of blood vessels is determined by the following factors: the scattering and absorption characteristics of skin at different wavelengths, the oxygenation state of blood, which affects its absorption properties, the diameter and the depth of the vessels, and the visual perception process.[2]
Function
Veins serve to return blood from organs to the heart. Veins are also called "capacitance vessels" because most of the blood volume (60%) is contained within veins. In systemic circulation oxygenated blood is pumped by the left ventricle through the arteries to the muscles and organs of the body, where its nutrients and gases are exchanged at capillaries, the blood then enter venules, then veins filled with cellular waste and carbon dioxide. The de-oxygenated blood is taken by veins to the right atrium of the heart, which transfers the blood to the right ventricle, where it is then pumped through the pulmonary arteries to the lungs. In pulmonary circulation the pulmonary veins return oxygenated blood from the lungs to the left atrium, which empties into the left ventricle, completing the cycle of blood circulation.
The return of blood to the heart is assisted by the action of the skeletal-muscle pump, and by the thoracic pump action of breathing during respiration. Standing or sitting for a prolonged period of time can cause low venous return from venous pooling (vascular) shock. Fainting can occur but usually baroreceptors within the aortic sinuses initiate a baroreflex such angiotensin II and norepinephrine stimulate vasoconstriction and heart rate increases to return blood flow. Neurogenic and hypovolaemic shock can also cause fainting. In these cases, the smooth muscles surrounding the veins become slack and the veins fill with the majority of the blood in the body, keeping blood away from the brain and causing unconsciousness. Jet pilots wear pressurized suits to help maintain their venous return and blood pressure.
The arteries are perceived as carrying oxygenated blood to the tissues, while veins carry deoxygenated blood back to the heart. This is true of the systemic circulation, by far the larger of the two circuits of blood in the body, which transports oxygen from the heart to the tissues of the body. However, in pulmonary circulation, the arteries carry deoxygenated blood from the heart to the lungs, and veins return blood from the lungs to the heart. The difference between veins and arteries is their direction of flow (out of the heart by arteries, returning to the heart for veins), not their oxygen content. In addition, deoxygenated blood that is carried from the tissues back to the heart for reoxygenation in systemic circulation still carries some oxygen, though it is considerably less than that carried by the systemic arteries or pulmonary veins.
Although most veins take blood back to the heart, there is an exception. Portal veins carry blood between capillary beds. For example, the hepatic portal vein takes blood from the capillary beds in the digestive tract and transports it to the capillary beds in the liver. The blood is then drained in the gastrointestinal tract and spleen, where it is taken up by the hepatic veins, and blood is taken back into the heart. Since this is an important function in mammals, damage to the hepatic portal vein can be dangerous. Blood clotting in the hepatic portal vein can cause portal hypertension, which results in a decrease of blood fluid to the liver.
Also transports proteins and other materials throughout the body.
Classification
_Venenbild.jpg)
Veins are classified in a number of ways, including superficial vs. deep, pulmonary vs. systemic, and large vs. small.
- Superficial veins
- Superficial veins are those whose course is close to the surface of the body, and have no corresponding arteries.
- Deep veins
- Deep veins are deeper in the body and have corresponding arteries.
- Communicating veins
- Communicating veins (or perforator veins) are veins that directly connect superficial veins to deep veins.
- Pulmonary veins
- The pulmonary veins are a set of veins that deliver oxygenated blood from the lungs to the heart.
- Systemic veins
- Systemic veins drain the tissues of the body and deliver deoxygenated blood to the heart.
Clinical significance
Phlebology
Phlebology is the medical discipline that involves the diagnosis and treatment of disorders of venous origin. Diagnostic techniques used include the history and physical examination, venous imaging techniques and laboratory evaluation related to venous thromboembolism. The American Medical Association has added phlebology to their list of self-designated practice specialties. A medical specialist in Phlebology is termed a Phlebologist. A related image is called a phlebography
The American College of Phlebology (ACP) is the largest professional organization in the world dedicated to Phlebology. It is composed of physicians and healthcare professionals from a variety of medical backgrounds and holds an Annual Scientific Congress as well as many symposia that educate and train practitioners in this field in order to enhance the quality of patient care. ACP meetings are conducted to facilitate learning and sharing of knowledge regarding venous disease. The equivalent body for countries in the Pacific is the Australasian College of Phlebology, active in Australia and New Zealand.
The American Venous Forum (AVF) is the leading academic international consortium of venous and lymphatic specialists dedicated to improving patient care. Research in clinical and basic sciences is reported at the AVF annual meetings, along with the reports on new developments in diagnosis and treatment of venous diseases. The main body of the AVF consists of vascular surgeons and other physicians who specialized in management of not only simple varicose veins but the whole spectrum of venous and lymphatic diseases from congenital abnormalities to deep vein thrombosis to chronic venous diseases.
Venous diseases
Venous insufficiency
Main article: Chronic venous insufficiency
Venous insufficiency is the most common disorder of the venous system, and is usually manifested as spider veins or varicose veins. Several varieties of treatments are used, depending on the patient's particular type and pattern of veins and on the physician's preferences. Treatment can include Endovenous Thermal Ablation using radiofrequency or laser energy, vein stripping, ambulatory phlebectomy, foam sclerotherapy, lasers, or compression.
Postphlebitic syndrome is venous insufficiency that develops following deep vein thrombosis.[3]
Deep vein thrombosis
Main article: Deep vein thrombosis
Deep-vein thrombosis is a condition in which a blood clot forms in a deep vein, which can lead to pulmonary embolism and chronic venous insufficiency.
Thrombophlebitis
Main article: Thrombophlebitis
Thrombophlebitis is an inflammatory condition of the veins related to blood clots.
See also
- Artery
- Deep vein
- Deep vein thrombosis
- Peripheral vein
- Phlebologist
- Pulmonary circulation
- Superficial vein
- Varicose veins
References
 |
This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (January 2008) |
- ^ Maton, Anthea; Jean Hopkins, Charles William McLaughlin, Alexandra Senckowski, Susan Johnson, Maryanna Quon Warner, David LaHart, Jill D. Wright (1993). Human Biology and Health. Englewood Cliffs, New Jersey: Prentice Hall. ISBN 0-13-981176-1.
- ^ Appl Opt. 1996 Mar 1;35(7):1151. doi:10.1364/AO.35.001151. Why do veins appear blue? A new look at an old question. Kienle A, Lilge L, Vitkin IA, Patterson MS, Wilson BC, Hibst R, Steiner R..
- ^ Kahn SR (August 2006). "The post-thrombotic syndrome: progress and pitfalls". Br. J. Haematol. 134 (4): 357–65. doi:10.1111/j.1365-2141.2006.06200.x. PMID 16822286.
External links
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Look up vein in Wiktionary, the free dictionary. |
- Merck Manual article on veins.
- American Venous Forum
- American College of Phlebology
- American Board of Phlebology
- American College of Phlebology Foundation
- Australasian College of Phlebology Information from the Australasian College of Phlebology Website
- In economics: Arterial and venous industries
- Animated Venous Access tutorials
Scientific publications
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This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
Translations:
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Vein
Dansk (Danish)
n. - blodåre, vene
v. tr. - mærke med årer, forgrene som årer
Nederlands (Dutch)
ader, bladader, nerf, ertsader, geest, stemming, overvloed, vleugelader, stijl, druk (figuurlijk), talent, topvorm, van aderen voorzien
Français (French)
n. - veine, nervure, veine (dans le marbre), veinure (dans le fromage), (Minér) veine, veine (un thème)
v. tr. - veiner
Deutsch (German)
n. - Ader, Vene, Zug, Stimmung
v. - ädern
Ελληνική (Greek)
n. - φλέβα, στρώμα, νεύρο, νεύρωμα, νεύρωση, (μτφ.) διάθεση, ύφος, πνεύμα, ταλέντο
v. - κάνω νερά σε (πόρτα κτλ.)
Italiano (Italian)
vena, venatura, filone
Português (Portuguese)
n. - veia (f), veio (m), talento (m), disposição (f), vocação (f)
v. - marmorear, cobrir de veias
Русский (Russian)
вена, канал, склонность, настроение, тон, покрывать сетью чего-л., распространяться
Español (Spanish)
n. - vena, nervadura, filón, veta
v. tr. - cubrir de venas, vetear, jaspear
Svenska (Swedish)
n. - åder, ådra, humör (fig.)
v. - ådra
中文（简体）(Chinese (Simplified))
血管, 叶脉, 静脉, 使成脉络, 像脉络般分布于
中文（繁體）(Chinese (Traditional))
n. - 血管, 葉脈, 靜脈
v. tr. - 使成脈絡, 像脈絡般分佈於
한국어 (Korean)
n. - 정맥, 잎맥, (인품, 행위 등에 나타난) 성격
v. tr. - ~에 맥을 넣다, (~위를) 맥처럼 뻗치다
日本語 (Japanese)
n. - 静脈, 血管, 気質, 葉脈, 翅脈, 気分, 鉱脈
العربيه (Arabic)
(الاسم) وريد, عرق, ميل, نزعه, عرق ملون في الرخام
עברית (Hebrew)
n. - וריד, עורק, נימה, רצועה, צלע עלה, צינורית חלולה בכנף של חרק, מצב-רוח, אווירה, נטייה, תכונה מובהקת, פס צבע בשיש וכו', נקיק סלע המלא בחומר גולמי כלשהו
v. tr. - מילא או כיסה בנימים, ברצועות וכו'
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