in the little brown bat , myotis lucifugus , topography and ultrastructure of the sinus node and the atrioventricular ( av ) node resemble those in large mammalian hearts , except that the p cells in the sinus node are smaller than those in the bat av node or those in the sinus node of slower hearts ( e.g. , dog , man ) .
C0004247
av node
C0018787
hearts