PSL301H1 Lecture 9: Heart as a Pump (Jan. 25, 2017)
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PSL301H1 Full Course Notes
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Sequence of events that occur when the heart beats - two phases. Overall aim: understand and integrate electrical activity, contraction, and blood flow in/out. You need this to have that pumping action - lowest and highest pressure. Blood flows from high pressure to low pressure. Events on right and left sides of heart are the same, but pressures are low on right. Right side does not need high pressure bc blood is only going to the lungs which aren"t too far from (pulmonary circuit) Left side needs a lot of pressure to push throughout the systemic circuit. Ventricles spend 2/3 of time in diastole, 1/3 of time they are contracting. Atria contracts only for 1/4 of the cycle. Late diastole: heart is filling until it is almost full (1), Then you have atrial systole (2 - contraction of atria) This pushes blood into the ventricles just before they contract (2)
