GENERAL HISTOLOGY

Detailed explanation-1: -Increased sympathetic activity produces dilatation of coronary resistance vessels and thus increases myocardial blood flow. This vasodilator response appears to be modulated, at least in part, by endothelial function.

Detailed explanation-2: -Increased parasympathetic stimulation decreases heart rate by decreasing SA node discharge rate and AV node conduction velocity. Ventricular contractility is not affected by parasympathetic activity when background sympathetic discharge is low but is enhanced in the presence of sympathetic activation.