Blockers, also known as inhibitors, are substances that prevent or reduce the activity of specific biological processes or reactions. They can interfere with enzymes, receptors, or other proteins, effectively slowing down or stopping their function. This property makes blockers useful in various medical treatments, such as managing high blood pressure or controlling pain. In pharmacology, blockers are often used to target specific pathways in the body. For example, beta-blockers are a class of medications that inhibit the effects of adrenaline on the heart, leading to decreased heart rate and blood pressure. Similarly, enzyme inhibitors can be used to treat conditions like cancer by blocking the activity of enzymes that promote tumor growth.