What sound does the heart make? What causes it?

The Cardiac Cycle DatE:

Learning Objectives Describe the passage of blood through the heart Explain how blood pressure affects and is affected by the valves Interpret graphs of blood pressure and explain what they show about the cardiac cycle

What sound does the heart make? What causes it? (Click the picture to hear it!)

Can you explain what is happening in the graph?

The Cardiac Cycle Watch the animation Describe what is happening There are three stages to the cycle, what do you think is going on in each one? Complete the card sort

Pressure through the cycle For each stage of the cycle write down whether the blood pressure is increasing or decreasing What effect does pressure have on the valves? (HINT: it depends on the valve and where the pressure is increasing) Sketch a simple graph for each of the aorta, ventricles and atria to show what happens to blood pressure throughout the cycle

Can you explain what is happening in the graph?

Suggest three questions you could be asked about this graph in an exam Try them out on a partner!

Describe the passage of a red blood cell through the circulatory system by referring to the pressure at each point Explain how blood is prevented from travelling in the wrong direction when the heart muscles contract Suggest why the aorta and arteries must have such a thick muscle wall and why this is not necessary in the veins