Heart blood vessels

• The heart is divided into four chambers, two atria (right and left) and two ventricles (right and left).
• Deoxygenated blood enters the right atrium through superior vena cava and inferior vena cava.
• Oxygenated blood returns to the heart via pulmonary veins on the left side.
• Blood flows from the right side to the lungs through pulmonary arteries.
• During diastole, the heart muscle relaxes and blood fills the heart.
• During systole, the heart muscle contracts and blood is ejected from the heart.
• The cardiac cycle consists of systole and diastole.
• Oxygenated blood from lungs enters the left atrium through pulmonary veins.
• Blood flows to the right ventricle through tricuspid valve.
• Blood flows out of the right ventricle through pulmonary semilunar valves to the pulmonary artery.
• Blood flows from the right atrium to the right ventricle through tricuspid valve.
• From the right ventricle, deoxygenated blood goes to lungs through pulmonary artery.
• Blood flows from the left side to the body's tissues through systemic circulation.
• Pulmonary vein carries oxygenated blood back to the heart.
• Systemic circulation includes the coronary artery that supplies oxygenated blood to the myocardium.
• Atrial systole occurs when the atria contract simultaneously, pushing blood into the ventricles.
• Ventricular systole follows with contraction of both ventricles, forcing blood out of the heart.
• Diastolic pressure refers to the lowest pressure within an artery during relaxation phase.
• Valves prevent backflow of blood between chambers or out of the heart.