Blood circulation through the heart is a continuous process that involves the movement of oxygen-rich blood from the lungs to the rest of the body, and oxygen-poor blood from the body back to the heart and lungs.
This process involves the heart's four chambers and is divided into two main circulatory pathways: pulmonary circulation and systemic circulation.
Step-by-step Blood Circulation:
1. Return to the Heart:
Oxygen-poor blood enters the right atrium via the superior vena cava (upper body) and inferior vena cava (lower body).
2. Right Atrium to Right Ventricle:
The right atrium contracts, pushing blood through the tricuspid valve into the right ventricle.
3. Right Ventricle to Lungs:
The right ventricle contracts, sending blood through the pulmonary valve into the pulmonary artery.
Blood travels to the lungs to receive oxygen and release carbon dioxide.
4. Return to the Heart:
Oxygen-rich blood returns to the left atrium via the pulmonary veins.
5. Left Atrium to Left Ventricle:
The left atrium contracts, pushing blood through the mitral (bicuspid) valve into the left ventricle.
6. Left Ventricle to Body:
The left ventricle contracts, sending blood through the aortic valve into the aorta.
Oxygen-rich blood is distributed to the body's organs and tissues via arteries, arterioles, and capillaries.
7. Completion of the Circulatory Loop:
Oxygen-poor blood is collected from tissues through venules and veins, returning to the right atrium, and the cycle repeats.
