The drug type illustrated in the diagram as drug type 1 is a calcium channel blocker. The mode of action for calcium channel blockers is that they widen blood vessels (which is the process of vasodilation) which reduces blood pressure. They do this by preventing calcium ions from entering cells of the heart and blood vessel walls. Calcium ions cause contraction of the vascular smooth muscle found in the walls of blood vessels when they enter the muscle cells. The calcium ions are able to enter the muscle cells through a voltage dependent channel. As soon as the calcium enters the cell via this channel, the muscle contracts which causes the blood vessel walls to constrict (known as vasoconstriction). This narrows the vessels, causing
