KIN-3505 Lecture Notes - Xerostomia, Blind Experiment, Flecainide
6 Oct 2013
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Evidence based medicine is the conscientious, explicit and judicious use of the best available information. It is used to make decisions about the care of patients. Problem- a 8-15% mortality rate post heart attack (mi), half of which died of heart rate problems (arrhythmias). Sa node (innervated by vagus nerve x) = primary control (100bpm) Parasympathetic nervous system decreases hr via acetacholine (60-80bpm) Options for controlling hr: beta-blockers (class ii) reduce sympathetic input to cells (which decreases hr). They do this by binding/interfering with receptors for norepinephrine and epinephrine: na+ channel blockers (class i) na+ initiates depolarizations of a nerve cell (from a negative resting potential (-70mv)). Na+ blockers cause it to take longer to depolarize (for na+ to rush into cell) which slows hr: k+ channel blockers (class iii) more k+ inside cell, k+ initiates repolarization (k+ rushes out, decreases conc.
