vein

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Dictionary: vein (vān) pronunciation

1. Anatomy. Any of the membranous tubes that form a branching system and carry blood to the heart.
2. 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.
1. A transient attitude or mood.
2. A particular turn of mind: spoke later in a more serious vein.

tr.v., veined, vein·ing, veins.

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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Britannica Concise Encyclopedia: vein

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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 (see 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. See also circulation; varicose vein.

For more information on vein, visit Britannica.com.

Thesaurus: vein

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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.

Dental Dictionary: vein

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(vān)
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.

Sports Science and Medicine: vein

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Vessel carrying blood to the heart. A vein usually has thin walls and a series of one-way valves.

Veins
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Columbia Encyclopedia: vein

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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).

Health Dictionary: veins

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Blood vessels that return blood from the body tissues to the heart. (Compare arteries; see circulatory system.)

Veterinary Dictionary: vein

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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.

Gardener's Dictionary: vein

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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.

Geological Glossary: Vein

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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: vein

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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 .

Wikipedia: Vein

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For other uses, see Vein (disambiguation).

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 where appropriate. (June 2008)

Vein

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. They differ from arteries in structure and function; for example, arteries are more muscular than veins and they carry blood away from the heart.

1 Anatomy
- 1.1 Notable veins and vein systems
- 1.2 Color
2 Function
3 Classification
4 Clinical significance
- 4.1 Phlebology
- 4.2 Venous diseases
5 See also
6 References
7 External links
- 7.1 Scientific publications

Anatomy

Cross section of a vein showing a valve which prevents backflow

Veins generally 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 generally thin as veins do not function primarily in a contractile manner. The interior is lined with endothelial cells called tunica intima. Most veins have one-way flaps called venous valves that prevent blood from flowing back and pooling in the lower extremities due to the effects of gravity. These are infoldings of the tunica intima. The precise location of veins is much more variable from person to person than that of arteries.^[1]

Notable veins and vein systems

The greater saphenous vein is the most important superficial vein of the lower limb. First described by the Persian physician Avicenna, Saphenous derives its name from Safina, meaning hidden. This vein is "hidden" in its own fascial compartment in the thigh and only exits the fascia 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.

Color

Vein color is determined in large part by the color of venous blood, which is usually dark red 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 off. This phenomenon is the opposite of Rayleigh scattering, the reason the sky is blue.

Function

Veins serve to return blood from organs to the heart. 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, entering the 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 which helps maintain the extremely low blood pressure of the venous system. Fainting can be caused by failure of the skeletal-muscular pump. Long periods of standing can result in blood pooling in the legs, with blood pressure too low to return blood to the heart. 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.

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.

Classification

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.

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

Venous valves prevent reverse blood flow.

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 a professional organization of physicians and health care professionals from a variety of backgrounds. 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.

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. A variety of treatments are used depending on the patient's particular type and pattern of veins and on the physician's preferences. Treatment can include radiofrequency ablation, vein stripping, ambulatory phlebectomy, foam sclerotherapy, lasers, or compression.

Postphlebitic syndrome is venous insufficiency that develops following deep vein thrombosis.^[2]

Deep vein thrombosis

Main article: Deep vein thrombosis

Deep vein thrombosis is a condition where 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.

References

This article needs additional citations for verification.
Please help improve this article by adding reliable references. 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.
^ 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

Look up vein in Wiktionary, the free dictionary.

Merck Manual article on veins.
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

v • d • e Circulatory system: Arteries and veins (TA A12.2-3, GA 6.543/GA 7.641)

Systemic circulation	(Heart ) → Aorta → Arteries → Arterioles → Capillaries → Venules → Veins → Vena cava → (Heart)

Pulmonary circulation	(Heart) → Pulmonary arteries → (Lungs) → Pulmonary vein → (Heart)

Blood vessels	Endothelium · Tunica intima · Tunica media · Tunica externa Vasa vasorum · Vasa nervorum Rete mirabile · Arteriovenous anastomosis

Arteries	Nutrient artery

Veins	Vena comitans · Superficial vein · Deep vein · Emissary veins · Venous plexus

vascular navs: anat/physio/dev, noncongen/systemic vasculitis/congen/neoplasia, symptoms+signs/eponymous, proc

Veins (emissary, jugular and others) of head and neck (drainage patterns can vary) (TA A12.3.04-06, GA 7.644)

External jugular

Retromandibular	maxillary (pterygoid plexus) · superficial temporal (anterior auricular)

Direct	posterior auricular transverse cervical · suprascapular · anterior jugular (jugular venous arch)

Internal jugular

Diploic/brain

Facial/common facial

frontal · supraorbital · angular · superior labial · inferior labial · deep facial

Direct

lingual (dorsal lingual, deep lingual, sublingual) · pharyngeal · superior thyroid (superior laryngeal) · middle thyroid

Brachiocephalic

Vertebral	occipital (occipital emissary) · suboccipital venous plexus deep cervical

Direct	inferior thyroid (inferior laryngeal) · thymic

v • d • e Veins of upper limbs (TA A12.3.08, GA 7.660)

superficial - hand/forearm	Dorsal digital · Dorsal metacarpal · Dorsal network · Palmar digital · Intercapitular

superficial - arm	Cephalic · Median cubital · Accessory cephalic · Basilic · Median antebrachial

deep - hand/forearm	Palmar metacarpal · Superficial palmar arch · Deep palmar arch

deep - arm	Radial · Ulnar · Brachial · Axillary

Veins of the torso (TA A12.3.01-04, 07, 09-10, GA 7.664)

Thorax

Vertebral column

vertebral venous plexuses (external, internal) · spinal (posterior, anterior) · basivertebral · intervertebral

Abdomen/pelvis

To azygos system

ascending lumbar (subcostal)

IVC
(Systemic)

To IVC or left renal vein

inferior phrenic · hepatic (central veins of liver, liver sinusoid) · suprarenal · renal · gonadal (ovarian ♀/testicular ♂, pampiniform plexus ♂) · lumbar · common iliac

Common iliac

Unpaired	median sacral vein

External iliac	inferior epigastric · deep circumflex iliac vein

Internal iliac	posterior: iliolumbar · superior gluteal · lateral sacral anterior: inferior gluteal · obturator · uterine ♀ (uterine plexus ♀) · vesical (vesical plexus, prostatic plexus ♂, deep of penis ♂/clitoris ♀, posterior scrotal ♂/labial ♀) · vaginal plexus/vein ♀ · middle rectal · internal pudendal (inferior rectal, bulb of penis ♂/vestibule ♀) · rectal plexus

Portal vein
(Portal)

Splenic	short gastric · left gastroepiploic · pancreatic · inferior mesenteric (superior rectal, left colic)

Superior mesenteric	right gastroepiploic · pancreaticoduodenal · jejunal · ileal · middle colic · right colic · ileocolic (appendicular)

Direct	cystic · left gastric/esophageal · right gastric · paraumbilical

v • d • e Veins of lower limbs (TA A12.3.11, GA 7.669)

thigh	femoral · profunda femoris · popliteal

deep leg	fibular · anterior tibial · posterior tibial

superficial leg	small saphenous · great saphenous (external pudendal, superficial of penis ♂/clitoris ♀)

foot	dorsal arch · dorsal metatarsal · dorsal digital · plantar arch · plantar metatarsal · common digital · plantar digital

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)

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Translations: Vein

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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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