2.6

• Aorta


  Main artery which carries oxygenated blood from the heart
• Arteries


  Blood vessels that carry uxygenated blood away from the heart (except for the pulmonary artery)
• Atrioventricular (AV) valves


  Consists of the tricuspid and bicuspid valve
• Atrioventricular node (AVN)


  Located in the centre of the heart, receives impulses from SAN and then sends impulses down fibres in the central wall of the heart and then up through the walls of the ventricles, causing ventricular systole
• Atrium (right/left)


  Upper chambers of the heart which receive blood from veins
• Bicuspid valve


  Located between the left atrium and left ventricle, opens due to a build-up of pressure in the left atrium
• Blood pressure


  Measure of the force that your heart uses to pump blood around your body
• Capillary


  Tiny blood vessels with walls one-cell thick where exchange of materials occurs
• Cardiac cycle


  Pattern of contraction and relaxation of the heart during one complete heartbeat
• Cardiac output


  Volume of blood pumped through each ventricle per minute, determined by heart rate and stroke volume
• Diastole


  Relaxation of the heart muscle
• Heart


  Muscular organ that pumps blood around the body
• Heart rate


  Number of heart beats per minute
• Medulla


  Part of the brain controlling breathing, heart rate and peristalsis
• Peristalsis


  Involuntary constriction and relaxation of the muscles in the digestive tract that moves food
• Pulmonary artery


  Artery which carries deoxygenated blood from the heart to the lungs
• Pulmonary vein


  One of the four veins that carries oxygenated blood to the heart from the lungs
• Samilunar valves


  Stop the back flow of blood into the heart, one where the aorta leaves the left ventricle and another where the pulmonary artery leaves the right ventricle
• Septum


  Separates the right-hand and left-hand side of the heart
• Sino-atrial node (SAN)


  Located in the wall of the right atrium and sets the rate at which the heart contracts
• Stroke volume


  Volume of blood pumped from the heart within each beat
• Systole


  Contraction of the heart muscle
• Tricuspid valve


  Located between the right atrium and right ventricle, opens due to a build-up of pressure in the right atrium
• Vein


  Blood vessel with valves that transports deoxygenated blood to the heart (except from the pulmonary vein)
• Vena cava


  One of the two veins that carries deoxygenated blood to the heart from the body systems
• Ventricle (right/left)


  Lower chamber of the heart that receives blood from the atrium and pumps it into the arteries
• The heart is divided into two halves - the right-hand side and the left-hand side
• The right-hand side of the heart is responsible for pumping deoxygenated blood to the lungs
• The left-hand side of the heart pumps oxygenated blood around the body
• Each side of the heart consists of an atrium and a ventricle, which are two connected chambers
• Main blood vessels that take blood into and out of the heart

  • Aorta
  • Vena Cava
  • Pulmonary Artery
  • Pulmonary Vein
• Cardiac output calculation


  1. Cardiac Output = Stroke Volume x Heart Rate

  2. Units: ml/min or l/min

  3. SV: ml or l

  4. HR: beats per min (bpm)
• The left and right ventricles pump the same volume of blood through the aorta and pulmonary artery
• Cardiac cycle


  1. During diastole, blood returning to the atrium flows into the ventricles. The higher pressure in the arteries closes the SL valves

  2. Atrial systole transfers the remainder of the blood through the atrioventricular (AV) valves to the ventricles

  3. Ventricular systole closes the AV valves and pumps the blood out through the semilunar (SL) valves to the aorta and pulmonary artery
• The opening and closing of the AV and SL valves are responsible for the heart sounds heard with a stethoscope
• Blood pressure


  Increases during ventricular systole and decreases during diastole, measured using a sphygmomanometer
• A typical blood pressure reading for a young adult is 120/80 mmHg (systolic/diastolic pressure)
• Hypertension (high blood pressure) is a major risk factor for many diseases including coronary heart disease
• Cardiac conducting system


  1. The heartbeat originates in the heart itself. The sino-atrial node (SAN) sets the rate at which the heart contracts

  2. The SAN sends out an impulse which are carried through the muscular wall of both atria, causing atrial systole

  3. The impulse is then passed to the atrioventricular node (AVN)

  4. Once the impulse from the SAN reached the AVN, the impulse is passed to conducting fibres which travel down the central wall of the heart

  5. The impulse then splits and travels up the left and right ventricles causing them to contract simultaneously (ventricular systole)
• Impulses in the heart generate currents that can be detected by an electrocardiogram (ECG)