Long answer!

Norepinephrine (i.e. sympathetic system hormone) binds to beta
receptors on the SA nodal cells to increase the heart rate, on the
cardiomyocytes to increase contractility and on the SMCs of blood
vessels to cause vasodilation. Compare and contrast the molecular
mechanisms at the intracellular level that bring about each of the
aforementioned effects. Make sure to name the key molecular players
involved and their effects on the cell physiology.