Heart Pt3

Question 1

Define the regular heart beat

Answer 1

SAN (pacemaker) sets rhythm. Sending out regular waves of electricity. Causes right atria to contract. Collagen prevents electricity passing onto ventricles directly. Instead, it goes to the AVN. AVN passes this onto the bundle of His but there is a delay. Ventricles contract after atria empty. His is a group of muscle fibres responsible for conducting the waves of electrical activity to purkyne tissue. This then carries the waves of electrical activity into muscle walls or ventricles causing simultaneous contraction.