Left atrium
It is the most posterior thin walled chamber of the heart. It receives blood from the lungs via 4 pulmonary veins
The left atrium of the heart forms from two different parts as it develops. A front half and a back half
The front half of the left atrium connects to a part called the left auricle and contains a special kind of muscles.
Left auricle of heart
The left auricle of heart is an outpouching that is located in the upper part of the left atrium, in front of the left superior pulmonary vein. It has a narrow-base origin.
Pectinate muscles of left atrium
They are raised muscular bands that are situated inside the left auricle.
Smooth part of left atrium
The back half, is the area where the four veins from the lungs connect. This part is smooth.
Sinus of pulmonary veins
The receiving chamber for the pulmonary veins is known as the sinus of pulmonary veins. It is the area where the oxygenated blood is funnelled from the lungs into the heart.
Openings of pulmonary veins
The pulmonary veins open into the sinus of pulmonary veins in the left atrium via 4 openings that are known as the openings of pulmonary veins.
Body of left atrium
In continuation with the sinus of the pulmonary veins is the body of the left atrium. This part represents the area where the collected blood from the lungs is stored temporarily before being pumped into the left ventricle.
Vestibule of left atrioventricular valve
Surrounding the left atrioventricular valve is an area that is known as the vestibule of left atrioventricular valve. This region acts as a critical juncture for blood flow between the chambers.
Interatrial septum
The left atrium is separated from the right atrium by the interatrial septum. This septum serves as an essential barrier distinguishing the heart’s left atrium and right atrium.