AMY-2A Lecture Notes - Lecture 5: Qt Interval, Purkinje Fibers, Afterload
Document Summary
Pacemaker cells, contractile cells, depolarization, hyperpolarization, na, k, Action potential: leaky na, fast ca, volt k. Pacemaker cells (autorhythmic cells): in ra, set heart rate but don"t contribute to force of heartbeat. Conduction cells: sends action potentials between pacemaker and contractile cells. Action potential: leaky ca, fast na, volt k, slow ca. Contractile cells: mechanical force, atrial and ventricle walls factors affecting cardiac output: bainbridge principle, preload, afterload. Preload- ventricles are most related to preload, it is how much the ventricles expand and how much blood they able to push into next area. Starling"s law is related to the ventricle, the stretch that occurs before contraction is positively correlated with amount of blood pushed out. Afterload- function of the heart is to get oxygenated blood out to the rest of the body, after load is the back pressure in the aorta that the left ventricle has to push against to get blood out.
