Editing Blood (section)

===Circulatory system===
[[File:Diagram of the human heart (cropped).svg|thumb|Circulation of blood through the human heart]]

{{main|Circulatory system}}
Blood is circulated around the body through [[blood vessels]] by the pumping action of the [[heart]]. In humans, blood is pumped from the strong [[left ventricle]] of the heart through [[arteries]] to peripheral [[Tissue (biology)|tissues]] and returns to the right [[Atrium (heart)|atrium]] of the heart through [[veins]]. It then enters the right [[Ventricle (heart)|ventricle]] and is pumped through the [[pulmonary artery]] to the [[lungs]] and returns to the left atrium through the [[pulmonary veins]]. Blood then enters the left ventricle to be circulated again. Arterial blood carries oxygen from inhaled air to all of the cells of the body, and [[venous blood]] carries carbon dioxide, a waste product of [[metabolism]] by [[Cell (biology)|cells]], to the lungs to be exhaled. However, one exception includes pulmonary arteries, which contain the most deoxygenated blood in the body, while the pulmonary veins contain oxygenated blood.

Additional return flow may be generated by the movement of [[skeletal muscles]], which can compress veins and push blood through the valves in veins toward the [[right atrium]].

The blood circulation was described by [[William Harvey]] in 1628.<ref>{{cite web |title=Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus |url=http://www.rarebookroom.org/Control/hvyexc/index.html |first=William |last=Harvey | name-list-style = vanc |author-link=William Harvey |language=la |year=1628 |url-status=live |archive-url=https://web.archive.org/web/20101127002138/http://rarebookroom.org/Control/hvyexc/index.html |archive-date=27 November 2010 }}</ref>