Cardiac Performance, Dr. D. Penney
Actions of Vagal Parasympathetic Neurons to the Heart (through release of acetylcholine)
...... Site ................................ Action .......................................... Affecting ......
sino-atrial node ................... decreases heart rate ................................ chronotropicity
atrial myocardium ................ decreases atrial force .............................. inotropicity
atrio-ventricular node ............ slowed AV conduction ............................ chronotropicity
atrio-ventricular node ............ delayed conduction / increased refractoriness ... chronotropicity
Note: There are few/no parasympathetic nerve endings on the ventricular myocardium, so while acetylcholine is a potential negative inotrope for the ventricles, it is not released there.
Last changed 02/17/03
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