Structure of the Heart (OCR GCSE Physical Education (PE)): Revision Note

Heart: structure

• The heart has walls made up of cardiac muscle which contracts and enables blood to be pumped around the body

• The heart consists of four chambers;  

  • Two chambers at the top are called the atria (plural of atrium)

    • they receive blood from either the body or the lungs and pump it to the lower chambers 

  •  Two chambers at the bottom are called the ventricles  

    • they receive blood from the atria and pump it to either the body or the lungs

    • the left ventricle wall is much thicker  

• The septum separates the left and right side to prevent oxygenated and deoxygenated blood mixing 

• Valves within the heart prevent blood from flowing backwards

  • The tricuspid valve prevents back flow of blood from the right ventricle to the right atrium

  • The bicuspid valve prevents back flow of blood from the left ventricle to the left atrium

  • The semilunar valves stop the back flow of blood into the heart

    • There is a semilunar valve where the aorta leaves the left ventricle and another where the pulmonary artery leaves the right ventricle

Blood vessels of the heart

• The four main blood vessels that take blood into and out of the heart are as follows:

  • The aorta

    • The largest artery that carries oxygenated blood away from the left ventricle to the body

  • The vena cava

    • The largest vein that carries deoxygenated blood from the body back to the heart

    • Enters the right atrium

  • The pulmonary artery

    • Carries deoxygenated blood away from the right ventricle to the lungs

  • The pulmonary vein

    • Carries oxygenated blood from the lungs to the heart

    • Enters the left atrium