How does blood flows through the heart?
Our heart carries blood to the arteries and supplies oxygen and nutrients to all the body tissues, which is an essential job. Regular uninterrupted blood flow is important to sustain life as we know fresh oxygen and vital nutrients reach all over in the body through the blood. In a healthy heart, blood flows in one way through all the four chambers in the heart with the help of the valves.
Blood supply to the heart is separate through the cardiac arteries that provide oxygen to the tissues of the heart as the blood within the heart is not used for oxygenation by the heart.
One atrium on top and one ventricle on lower side situated at the right side of the heart are referred as ‘Right Heart’. Similarly ‘Left Heart’ consists of one atrium on top of left heart and one ventricle on the lower side of the heart. In general, due to the placement of these chambers, the heart is referred as the right heart and the left heart. Basically left and right heart name is given because of the division in the heart chambers.
The atria and ventricle on each side of the heart are linked together by valves that prevent backflow of blood. A wall of muscle called the septum separates the two sides of the heart. The right and left sides of the heart work together. The whole process is repeated all the time resulting blood to flow constantly to the heart, lungs and the body. The heart circulates blood through two pathways: the pulmonary route and the systemic route. The left heart deals with systemic circulation, while the right heart deals with pulmonary circulation.
Right Side of the Heart
The right side of the heart (i.e. right atrium and right ventricle) receives blood which has less oxygen from the systemic circulation (through the inferior and superior vena cava, two large veins).
As the atrium contracts, blood flows from right atrium into the right ventricle through the open tricuspid valve.
When blood level is full in the right ventricle, the tricuspid valve closes to prevent backflow of the blood into the atrium at the time of contraction.
Thereafter as the ventricle contracts this blood leaves the heart and pumped into the pulmonary circulation. The pulmonary trunk carries blood through the lungs where it gets fresh oxygen and releases carbon dioxide.
The blood in the lungs returns to the heart through the pulmonary veins. From the pulmonary veins, blood enters the heart again in the left atrium.
Left Side of the Heart
Once the oxygenated blood through pulmonary veins from the lungs enters the left side (i. e. left atrium and left ventricle) of the heart and pumps it into the aorta.
The left atrium contracts to pump blood through the bicuspid (mitral) valve into the left ventricle.
When the ventricle is full, the mitral valve shuts. This prevents blood from flowing backward into the atrium while the ventricle contracts.
As the left ventricle contracts, blood leaves the heart through the aortic valve which is called semilunar valve into the aorta. From the aorta, blood enters into the systemic circulation via arteries throughout the body tissues where the oxygen is used and metabolized to carbon dioxide.
This whole process is done and then blood returns to the heart via the large veins and the same gets repeated again.