B – The Cardiovascular System The structure and function of arteries, capillaries and veins The structure and function of the heart Pathology of cardio vascular disease (CVD) Blood glucose levels and obesity

KA 6: The structure and function of the heart 2.6 Key Topics REVISION: Structure of the heart (D) Blood Pressure (A) Cardiac function and cardiac output (B) Cardiac cycle (C) The structure and function of cardiac conducting system

KA 6b: Learning Outcomes State what is meant by the cardiac cycle Define and describe what happens during atrial systole Define and describe what happens during ventricular systole Define and describe what happens during diastole Describe the action of AV and SL valves during the cardiac cycle Describe the changes in pressure during the cardiac cycle Interpret graphs of pressure changes in heart and blood vessels

2 minutes – think/pair/share This animation shows REPEATED cardiac cycles… What do think the cardiac cycle is? What do you think makes ONE cycle?

The Cardiac Cycle The cardiac cycle is the name of the pattern of contraction (systole) and relaxation (diastole) in one complete heartbeat.

The Cardiac Cycle ATRIAL SYSTOLE Atrial systole is when the atria contract to transfer blood through the open atrio-ventricular (AV) valves to the ventricles.

The Cardiac Cycle VENTRICULAR SYSTOLE Ventricular systole closes the AV valves. The ventricle contract and pump the blood out through the open semi lunar (SL) valves to the aorta and pulmonary artery.

The Cardiac Cycle DIASTOLE During diastole blood returning to the relaxed atria flows into the relaxed ventricles. In diastole the higher pressure in the arteries closes the SL valves.

The Cardiac Cycle

Cardiac Cycle Videos https://www.youtube.com/watch?v=5tUWOF6wEnk http://highered.mheducation.com/sites/0072495855/student_view0/chapter22/animation__the_cardiac_cycle__quiz_1_.html http://www.educationscotland.gov.uk/highersciences/humanbiology/animations/cardiaccycle.asp

Task: Use your card sort to describe what is going on in this graph! “DUB” Blood flows from the atria into the ventricles through the atrioventricular valves. The atria contract. The semilunar valves close. The ventricles contract. The atrioventricular valves close. Blood flows through the semilunar valves into the aorta (from the left ventricle) and the pulmonary artery (from the right ventricle). Heart muscle relaxes. The semilunar valves are closed. Blood flows into the atria (right – from vena cava, left – from pulmonary vein). The atrioventricular valves are open to allow blood to move into the ventricles. “LUB” 0 0.2 0.4 0.6 0.8 The atrioventricular valves are open to allow blood to move into the ventricles. The atria contract. The SL valves open. The AV valves close. The ventricles contract Heart muscle relax The SL valves are closed

Colour code each of the 3 lines! The Cardiac Cycle The opening and closing of the AV and SL valves are responsible for the heart sounds heard with a stethoscope (‘lub’ and ‘dub’). TASK: Colour code each of the 3 lines!

KA 6b: Learning Outcomes State what is meant by the cardiac cycle Define and describe what happens during atrial systole Define and describe what happens during ventricular systole Define and describe what happens during diastole Describe the action of AV and SL valves during the cardiac cycle Describe the changes in pressure during the cardiac cycle Interpret graphs of pressure changes in heart and blood vessels