Pressure and volume changes of the heart

• Mammals have a closed circulatory system (blood is confined to vessels) and this allows the pressure within them to be maintained and regulated
• Cardiac output - The volume of blood pumped by one ventricle of the heart in one minute
• Heart rate - Beats of the heart per minute
• Stroke volume - Volume of blood pumped out at each beat
• Cardiac output = heart rate x stroke volume