Cardiac pacemaker controls the rate of contraction for the entire heart muscle because its cells have the quickest rate of spontaneous depolarization, thus they initiate action potentials the quickest. The action potential generated by the SA node passes down the electrical conduction system of the heart, and depolarizes the other potential pacemaker cells (AV node) to initiate action potentials before these other cells have had a chance to generate their own spontaneous action potential, thus they contract and propagate electrical impulses to the pace set by the cells of the SA node. This is the normal conduction of electrical activity in the
Common name objects, typically an incomplete and informal classification, in which some names are degenerate examples in that they are unique and lack reference to any other name, as is the case with say, "ginkgo", "okapi", and "ratel". Folk taxonomy, which is a classification of objects using common names, has no formal rules and need not be consistent or logical in its assignment of names, so that say, not all flies are called flies (for example Braulidae, the so-called "bee lice") and not every animal called a fly is indeed a fly (such as dragonflies and mayflies). In contrast, scientific or biological