Herzvorhöfen

Herzvorhöfen, also known as atria, are the two upper chambers of the heart. The right atrium receives deoxygenated blood from the body, while the left atrium receives oxygenated blood from the lungs. These chambers play a crucial role in the circulatory system by collecting blood and then pumping it into the ventricles below.

The right atrium receives blood from the superior vena cava and the inferior vena cava, which are large veins that carry blood from the upper and lower parts of the body, respectively. It also receives blood from the coronary sinus, which drains blood from the heart muscle itself. From the right atrium, blood flows through the tricuspid valve into the right ventricle.

The left atrium receives oxygenated blood from the pulmonary veins, which come from the lungs. This oxygenated blood then passes through the mitral valve (also known as the bicuspid valve) into the left ventricle. The coordinated contraction and relaxation of the atria and ventricles ensure the continuous circulation of blood throughout the body, delivering oxygen and nutrients to tissues and removing waste products. The atria are thinner-walled than the ventricles because they only need to pump blood a short distance to the adjacent ventricles. Their rhythmic contractions are initiated by the sinoatrial node, the heart's natural pacemaker.