The heart is made up of four chambers, two atria (top) and two ventricles (bottom). The right side pumps blood to the lungs where it picks up oxygen and gets rid of carbon dioxide.
Blood flows through one way valves between the chambers so that it only moves forward.
The left side of the heart receives oxygen-rich blood from the lungs and then pumps it out into the rest of the body.
Blood throws into the atria from vena cava and pulmonary vein
Atria contract pushing blood into ventricles
Ventricles contract forcing blood into pulmonary artery and the aorta out of the heart
Blood flows to organs through arteries and returns through veins
Resting heart rate is controlled by a natural pacemaker which produces small electrical impulses which spreads to the muscle cells causing them to contract
An artificial pacemaker is a device that sends electrical impulses to the heart to keep it beating at a regular rate
There are 3 different types of blood vessel
Arteries - carry blood away from heart
Capillaries - exchange of materials at the tissues
Veins - carry blood to the heart
Artery features
strong + elastic walls as blood in arteries is at high pressure
thick walls
Capillaries
Very small lumen
Thin wall (one cell thick)
Permeable walls so substances can diffuse through them
Supply food + oxygen and take away carbon dioxide
Veins
walls are less thick as blood at low pressure
have a large lumen
Veins have valves to keep the blood flowing in the right direction
