Circulatory System The circulation system supplies oxygen and nutrients to tissues round the body and carries away wastes.

The Heart Deoygenated blood flows from the body into the heart in veins From the Right Atrium through a valve To the Right Ventricle Through another valve out the artery to the lungs Oxygenated blood flows back from the lungs in the vein from the lungs From the Left Atrium To the Left Ventricle Through another valve out the artery to the body Through another valve

Arteries, Capillaries & Veins Arteries Thick muscular walls l Oxygenated (except pulmonary artery) blood carried away from the heart l Blood at high pressure, can feel pulse when close to skin Veins Thin muscular walls l Deoxygenated (except pulmonary vein) blood carried back to the heart l Blood at low pressure l Valves stop back flow of blood between heart beats Capillaries Walls one cell thick l Dissolved gases, soluble food and other soluble substances to pass into and out of capillarie l Exchange materials between blood and tissues