What happens to heart rate and contractility when Beta 1 receptors are blocked?

Blocking beta-1 receptors has a significant impact on heart function. Beta-1 adrenergic receptors are primarily located in the heart, where their activation leads to an increase in heart rate (positive chronotropic effect) and enhanced myocardial contractility (positive inotropic effect). Therefore, when these receptors are blocked, the opposite effect occurs.

The inhibition of beta-1 receptors results in a decrease in heart rate and contractility. The reduction in heart rate can lower the cardiac output, which is the amount of blood the heart pumps per minute, and the decreased contractility can lead to a reduced force of contraction of the heart muscle. This pharmacological action is crucial in the treatment of conditions such as hypertension and heart failure, where reducing the heart's workload can be beneficial.

The other options do not accurately reflect the physiological effects of beta-1 receptor blockage. An increase in heart rate and contractility or no change contradicts the established effects of beta-blockade, as does the statement about decreased blood flow to muscles, which focuses on peripheral effects rather than the direct impact on cardiac function.