Pulmonary vein - wikipedia Pulmonary vein Pulmonary veins Anterior ( frontal ) view of the opened heart. White arrows indicate normal blood flow. Diagram of the alveoli with both cross-section and external view. Details Precursor truncus arteriosus System Circulatory system Drains from lungs Drains to left atrium Artery pulmonary artery Identifiers Latin venae pulmonales MeSH D011667 TA A12. 3.02. 001 FMA 70827 Anatomical terminology ( edit on Wikidata ) The pulmonary veins are the veins that transfer oxygenated blood from the lungs to the heart. The largest pulmonary veins are the four main pulmonary veins, two from each lung that drain into the left atrium of the heart. The pulmonary veins are part of the pulmonary circulation. Contents 1 Structure 1.1 Variation 2 Function 3 Clinical significance 4 Additional images 5 See also 6 References 7 External links Structure Two main pulmonary veins emerge from each lung hilum, receiving blood from three or four bronchial veins apiece and draining into the left atrium. An inferior and superior main vein drains each lung, so there are four main veins in total. At the root of the lung, the right superior pulmonary vein lies in front of and a little below the pulmonary artery ; the inferior is situated at the lowest part of the lung hilum. Behind the pulmonary artery is the bronchus. The right main pulmonary veins ( contains oxygenated blood ) pass behind the right atrium and superior vena cava ; the left in front of the descending thoracic aorta. Variation Occasionally the three lobar veins on the right side remain separate, and not infrequently the two left lobar veins end by a common opening into the left atrium. Therefore, the number of pulmonary veins opening into the left atrium can vary between three and five in the healthy population. The two left lobar veins may be united as a single pulmonary vein in about 25 % of people ; the two right veins may be united in about 3 %. Function Further information : Pulmonary circulation The pulmonary veins play an essential role in respiration, by receiving blood that has been oxygenated in the alveoli and returning it to the left atrium. Clinical significance As part of the pulmonary circulation they carry oxygenated blood back to the heart, as opposed to the veins of the systemic circulation which carry deoxygenated blood. A rare genetic defect of the pulmonary veins can cause them to drain into the pulmonary circulation in whole or in part, this is known as a total anomalous pulmonary venous connection, or partial anomalous pulmonary connection, respectively. Additional images Computed tomography of a normal lung, with different levels of pulmonary veins. Bronchial anatomy Transverse section of thorax, showing relations of pulmonary artery. Pulmonary vessels, seen in a dorsal view of the heart and lungs. See also This article uses anatomical terminology ; for an overview, see Anatomical terminology. References This article incorporates text in the public domain from page 642 of the 20th edition of Gray 's Anatomy ( 1918 ) Jump up ^ Drake, Richard L. ; Vogl, Wayne ; Tibbitts, Adam W.M. Mitchell ; illustrations by Richard ; Richardson, Paul ( 2005 ). Gray 's anatomy for students ( Pbk. ed. ). Philadelphia : Elsevier / Churchill Livingstone. ISBN 978 - 0 - 443 - 06612 - 2. ^ Jump up to : Skandalakis, editor in chief John E. ( 2004 ). `` Chapter 7. Pericardium, Heart, and Great Vessels in the Thorax ''. Skandalakis ' surgical anatomy : the embryologic and anatomic basis of modern surgery. Athens, Greece : PMP. pp. section titled ' Pulmonary veins '. ISBN 9603990744. CS1 maint : Extra text : authors list ( link ) External links Anatomy figure : 19 : 05 - 08 at Human Anatomy Online, SUNY Downstate Medical Center Illustration at infomat.net Arteries and veins Vessels Arteries Nutrient artery Arteriole Metarteriole Elastic artery Capillaries Types Continuous Fenestrated Sinusoidal Precapillary sphincter Precapillary resistance Veins Vena comitans Superficial vein Deep vein Emissary veins Venous plexus Venule Lymph Lymphatic vessel Lymph Lymph capillary Circulatory system Systemic Left heart → Aorta → Arteries → Arterioles → Capillaries → Venules → Veins → Vena cava → ( Right heart ) Pulmonary Right heart → Pulmonary arteries → Lungs → Pulmonary vein → Left heart Microanatomy Microvessel Microcirculation Tunica intima Endothelium Internal elastic lamina Tunica media Tunica externa Vasa vasorum Vasa nervorum Vascular nerves Rete mirabile Circulatory anastomosis Veins of the thorax and vertebral column Thorax Heart Coronary sinus Great cardiac ( Left marginal ) Posterior of the left ventricle Oblique of the left atrium ( Ligament of the left vena cava ) Middle cardiac Small cardiac vein Anterior cardiac ( Right marginal ) Smallest cardiac veins Right atrial veins Right ventricular veins Lungs Pulmonary veins superior vena cava Brachiocephalic internal thoracic anterior intercostal superior epigastric left superior intercostal supreme vertebral subclavian axillary : lateral thoracic thoracoepigastric dorsal scapular external jugular pericardiacophrenic internal jugular Azygos right superior intercostal bronchial intercostal / posterior intercostal 5 - 11 accessory hemiazygos / hemiazygos superior phrenic Vertebral column vertebral venous plexuses external internal spinal posterior anterior basivertebral intervertebral Anatomy portal Retrieved from `` https://en.wikipedia.org/w/index.php?title=Pulmonary_vein&oldid=847232751 '' Categories : Wikipedia articles incorporating text from the 20th edition of Gray 's Anatomy ( 1918 ) Veins of the torso Hidden categories : Pages with unresolved properties CS1 maint : Extra text : authors list Anatomy NAV infobox with use of other NAV parameters Talk Contents About Wikipedia Azərbaycanca Bosanski Català Deutsch Español فارسی Français Italiano עברית Latina Nederlands 日本 語 Norsk nynorsk Polski Português Русский Српски / srpski Srpskohrvatski / српскохрватски Suomi Svenska ไทย Türkçe 中文 15 more Edit links This page was last edited on 23 June 2018, at 20 : 59 ( UTC ). 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Question: where does the blood in the pulmonary vein come from
Answer: the lungs