Human Circulatory System Overview

Key Components of the Heart

Aorta: The main artery that carries oxygenated blood away from the heart to the rest of the body.
Superior Vena Cava: A large vein that carries deoxygenated blood from the upper half of the body to the right atrium of the heart.
Inferior Vena Cava: A large vein that carries deoxygenated blood from the lower half of the body to the right atrium of the heart.
Right Pulmonary Veins: Veins that carry oxygenated blood from the right lung to the left atrium of the heart.
Left Pulmonary Veins: Veins that carry oxygenated blood from the left lung to the left atrium of the heart.
Right Atrium: The upper right chamber of the heart that receives deoxygenated blood from the body.
Left Atrium: The upper left chamber of the heart that receives oxygenated blood from the lungs.
Right AV (Tricuspid) Valve: The valve that separates the right atrium from the right ventricle, preventing backflow during contraction.
Left AV (Bicuspid) Valve: The valve that separates the left atrium from the left ventricle, preventing backflow during contraction.
Right Ventricle: The lower right chamber of the heart that pumps deoxygenated blood to the lungs.
Left Ventricle: The lower left chamber of the heart that pumps oxygenated blood to the body.
Pulmonary Trunk: The vessel that carries deoxygenated blood from the right ventricle to the lungs.
Pulmonary Valve: The valve that controls blood flow from the right ventricle into the pulmonary trunk.
Aortic Valve: The valve that controls blood flow from the left ventricle into the aorta.

Blood Flow Pathway

Blood Entry into Right Atrium: Blood enters the right atrium from the superior and inferior venae cavae.
Flow to Right Ventricle: Blood in the right atrium flows through the right AV (tricuspid) valve into the right ventricle.
Contraction of Right Ventricle: The contraction of the right ventricle forces the pulmonary valve open.
Flow to Pulmonary Trunk: Blood flows through the pulmonary valve into the pulmonary trunk.
Blood Distribution to Lungs: Blood is distributed by the right and left pulmonary arteries to the lungs, where it unloads CO₂ and loads O₂.
Return from Lungs: Blood returns from the lungs via the pulmonary veins to the left atrium.
Flow to Left Ventricle: Blood in the left atrium flows through the left AV (bicuspid) valve into the left ventricle.
Contraction of Left Ventricle: The contraction of the left ventricle (simultaneous with step 3) forces the aortic valve open, allowing blood to flow through.
Flow to Aorta: Blood flows through the aortic valve into the ascending aorta.
Distribution to the Body: Blood in the aorta is distributed to every organ in the body, where it unloads O₂ and loads CO₂.
Circulation Completion: Blood returns to the heart via the venae cavae, completing the circuit.