What is the left atrium?
The left atrium is a hollow chamber that serves as a vessel and pump for blood entering the heart.
Human hearts contain four chambers: the left ventricle and right ventricle and the left atrium and right atrium. The left atrium is the chamber situated on the top left side – on the right when somebody faces you.
In men, the left atrial chamber has a diameter of approximately 30 to 40 millimeters, while in women it measures about 27 to 38 millimeters.
What is the left atrium’s function?
The chamber’s main function is to maintain blood flow to the heart.
Acting as a pump, it continuously passes along oxygen-rich blood entering from the pulmonary veins to the left ventricle (the main pumping chamber) by way of the bicuspid (aka mitral) valve. The blood is then pushed into the aorta (our largest artery) via the aortic valve and passes through the body.
Atrial contraction is initiated and regulated by the right atrium’s sinoatrial node, which is a natural pacemaker or impulse generator. This node triggers the cardiac cycle (our heartbeat), signalling blood to move from the left atrium, through the bicuspid valve, and into the left ventricular chamber.