What is the difference between these blood pressure medication classifications? Pharmacy student – need help.?

I need someone to explain the difference between a Calcium channel blocker medication, a beta – blocker, and an ACE inhibitor. I am a pre-Pharmacy student, and I really need someone to explain the difference please. Thanks so much for you help. Greatly appreciate it.

ACE Inhibitors work in the lungs by blocking the conversion of a specific protein from its inactive to its active form. This protein, in its active form, can cause constriction of small blood vessels, called arterioles, and exhert various other effects which can raise blood pressure. By blocking the formation of this active protein, blood pressure is lowered over time.

Beta blockers inhibit these normal epinephrine-mediated sympathetic actions, but have minimal effect on resting subjects. That is, they reduce the effect of excitement/physical exertion on heart rate and force of contraction, dilation of blood vessels and opening of bronchi, and also reduce tremor and breakdown of glycogen.

Many calcium channel blockers also slow down the conduction of electrical activity within the heart, by blocking the calcium channel during the plateau phase of the action potential of the heart (see: cardiac action potential). This results in a negative chronotropic effect resulting in a lowering of the heart rate and the potential for heart block. The negative chronotropic effects of calcium channel blockers make them a commonly used class of agents in individuals with atrial fibrillation or flutter in whom control of the heart rate is an issue.