definitions

• what is the atria

  two upper chambers of the heart
• what is the ventricle

  two bottom chambers of the heart
• what is the atrio ventricular valve

  found between the atrial and ventricular chambers of the heart to prevent blood flowing back into the atria when the ventricles contract
• what is the tendinous cords

  fibrous cords that attach the papillary muscle to the atrioventricular valves , preventing backflow of blood during the cardiac cycle
• what is the aorta

  large artery carrying oxygenated blood from the left ventricle
• what is the semi lunar valve

  found at the base of the aorta and pulmonary artery which prevent blood flowing back into the ventricles when the heart relaxes
• what is the systole

  time in heartbeat when cardiac muscle contracts
• what is diastole

  time in heartbeat when the cardiac muscle relaxes
• what is the sino-atrial node

  specialised muscle cells in the right atrium that start the cardiac cycle by sending impulses across the atria walls - known as hearts pacemakers
• what is the atrio ventricular node

  specialised muscle cells in the junction of the atria and ventricles that recieve impulses from the SAN and send impulses across the ventricle walls