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Right atrium
From Wikipedia, the free encyclopedia
| Right atrium | |
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| Anterior (frontal) view of the opened heart. White arrows indicate normal blood flow. | |
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| Interior of right side of heart. | |
| Latin | atrium dextrum |
| Gray's | subject #138 528 |
| MeSH | Right+Atrium |
| Dorlands/Elsevier | a_71/12167861 |
The right atrium (in older texts termed the "right auricle") is one of four chambers (two atria and two ventricles) in the human heart. It receives de-oxygenated blood from the superior and inferior vena cavae and the coronary sinus, and pumps it into the right ventricle through the tricuspid valve.
The sinoatrial node (SAN) is located within this chamber next to the vena cava. This is a group of pacemaker cells which spontaneously depolarise to create an Action Potential. The cardiac action potential then spreads across both atria causing them to contract forcing the blood they hold into their corresponding ventricles.
In early life, when a foetus is in the womb, the right atrium has a hole within its septum through to the left atrium, this makes them continuous with each other which is essential for foetal circulation. This junction is called the “Foramen Ovale”. Once born (usually within a year's time) the Foreman Ovale seals over and it is renamed as the “Fossa Ovalis”. The Fossa Ovalis is seen as an embryonic remnant.
The right atrium also holds the coronary sinus which is the opening of the vein that drains the myocardium itself. Attached to the right atrium is the right auricular appendix.
 Heart seen from above. |