ANP 1105 Lecture Notes - Lecture 14: Mitral Valve, Stroke Volume, Cardiac Output

• School: University of Ottawa
• Department: Anatomy and Physiology
• Course: ANP 1105
• Professor: Joanne Savory

Document Summary

Heart depolarizes and contracts w/o ns stimulation, although rhythm can be altered by. Coordinated heartbeat is a function of: a presence of gap junctions and intrinsic cardiac. Network of noncontractile (autorhythmic) cells initiate and distribute impuses to coordinate depolarization and contraction of heart. Sequence of excitation - process from initiaton at sa node to complete contraction takes ~0. 22s: sinoatrial (sa) node pacemaker of heart in right atrial wall; once it starts ap, it spreads throughout the heart. Inherent rate of 100x/min tempered by extrinsic factors. Impulse spread across atria and to av node: atrioventricular (av) node infereior interatrial septum. Delays impulses approximately 0. 1s b/c co2: allows atrial contration prior to ventricular contraction. Inherent rate of 50x/min in absence of sa node input: av bundle (bundle of his) in superior interventricular septum. Av bundle purkinje fibers depolarize 30x. min bentricular contraction immediately follows from apex toward atria. Rate of sa node depolarization regulated by ans.