- Pulmonary circulation
Pulmonary circulation is the portion of the
cardiovascular system which carriesoxygen -depletedblood away from the heart, to thelungs , and returns oxygenated blood back to the heart. The term is contrasted withsystemic circulation .Course
In the pulmonary circulation, deoxygenated blood exits the heart through the
pulmonary arteries , enters the lungs and oxygenated blood comes back throughpulmonary veins .The blood moves from right ventricle of the heart to the lungs back to the left atrium.Right heart
Oxygen-depleted blood from the
body leaves the systemic circulation when it enters theright heart , more specifically theright atrium through thesuperior vena cava . The blood is then pumped through thetricuspid valve (or right atrioventricular valve), into theright ventricle .Arteries
From the
right ventricle , blood is pumped through the pulmonarysemilunar valve into thepulmonary artery . This blood enters the twopulmonary arteries (one for each lung) and travels through thelungs .Lungs
The pulmonary arteries carry blood to the lungs, where
red blood cell s releasecarbon dioxide and pick up oxygen during respiration.Exchanges carbon dioxide for oxygen in the lungs.Veins
The oxygenated blood then leaves the lungs through
pulmonary veins , which return it to theleft heart , completing the pulmonary cycle. This blood then enters theleft atrium , which pumps it through the bicuspid valve, also called the mitral or left atrioventricular valve, into theleft ventricle . The blood is then distributed to the body through the systemic circulation before returning again to the pulmonary circulation.History
Pulmonary circulation was first discovered and published by
Ibn Nafis in his "Commentary on Anatomy in Avicenna's Canon" (1242), for which he is considered the father of circulatory physiology. [Chairman's Reflections (2004), "Traditional Medicine Among Gulf Arabs, Part II: Blood-letting", "Heart Views" 5 (2), p. 74-85 [80] .] It was later published byMichael Servetus in "Christianismi Restitutio " (1553).Since it was a theology work condemned by most of the Christian factions of his time, the discovery remained mostly unknown until the dissections ofWilliam Harvey in1616 .Embryonic
The pulmonary circulation loop is virtually bypassed in
fetal circulation . The fetal lungs are collapsed, and blood passes from the right atrium directly into the left atrium through theforamen ovale , an open passage between the two atria. When the lungs expand at birth, the pulmonary pressure drops and blood is drawn from the right atrium into the right ventricle and through the pulmonary circuit. Over the course of several months, theforamen ovale closes, leaving a shallow depression known as thefossa ovalis in the adult heart.References
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