Final answer:
Beta blockers, such as metoprolol and propranolol, are commonly used during a heart attack to slow the heart rate and decrease blood pressure. They are not used to treat stroke, asthma attacks, or broken bones. Their mechanism of action involves blocking the effects of adrenaline on β-receptors in the heart.
Step-by-step explanation:
Beta blockers are a class of medications that are commonly prescribed for various cardiovascular conditions. They work by binding to β-receptors, which are G-protein-linked receptors in the heart muscles, blocking the effects of adrenaline and noradrenaline (NE). Metoprolol and propranolol are two common beta blockers, with metoprolol specifically blocking the β1-receptor, and propranolol blocking β-receptors more generally. One primary use of beta blockers is during a heart attack to improve cardiac function in a compromised system by slowing the heart rate and diminishing blood pressure. They do this by inhibiting the stimulatory effect of adrenaline, thus producing an inhibitory effect on the heart rate and vasoconstriction. This can help prevent further damage to the heart muscle and reduce the risk of future cardiovascular events. While beta blockers can be used to treat high blood pressure, chest pain (angina), and certain arrhythmias, they are not the appropriate treatment for conditions such as stroke, asthma attacks, or broken bones. In the case of a heart attack or other instances where enhanced cardiac function is needed, beta blockers can be lifesaving.