The cardiovascular system in action 1/Cardiac function and cardiac output 2/ Cardiac cycle
The cardiovascular system in action 1/Cardiac function and cardiac output 2/ Cardiac cycle
Is there a difference between the volume of blood pumped by the right and the left ventricles? NO! What is the name given to the volume of blood pumped out of the heart to the body with each heartbeat? Stroke volume
The volume of blood pumped out of the heart to the body with each heartbeat
What is meant by cardiac output? It is the volume of blood pumped through each ventricle (i.e. out of the heart) per minute. Cardiac output is determined by the heart rate and stroke volume. How do you work out the cardiac output? By multiplying the heart rate by the stroke volume. CO = HR X SV What are the units of cardiac output? Litres/minute Check the video
The cardiovascular system in action 1/Cardiac function and cardiac output 2/ Cardiac cycle 3/ Cardiac conducting system
What is responsible for the heart sounds heard with a stethoscope? The opening and closing of the AV and SL valves What is name given to the contraction & relaxation of heart muscles? Contraction is the systole, relaxation is the diastole
Both sets of chambers are relaxed and ventricles fill passively
Atrial contraction forces a small volume of additional blood into ventricles Atrial systole
First phase of ventricular contraction pushes AV valves closed but does not create enough pressure to open semilunar valves Ventrical systole
As ventricular pressure rises and exceeds pressure in the arteries, the semilunar valves open and blood is ejected Ventrical systole
P P P As ventricles relax, pressure in ventricles falls, blood flows back into cusps of semilunar valves and snaps them closed. P P P P Diastole
What is the function of diastole? Blood returning to the atria flows into the ventricles. Explain the changes in blood pressure in diastole and their effect on valves. In diastole the higher pressure in the arteries compared to the pressure in the ventricles closes the SL valves. What is the function of systole? Atrial systole transfers the remainder of the blood through the atrio-ventricular (AV) valves to the ventricles. Ventricular systole closes the AV valves and pumps the blood out through the semi lunar (SL) valves to the aorta and pulmonary artery.
Pressure graph Watch this video from 12min45s to 15min n5KdjM n5KdjM
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