What effect does the sympathetic nervous system have on the heart?

The sympathetic nervous system plays a crucial role in the body's "fight or flight" response, significantly impacting cardiac function. When it is activated, it releases neurotransmitters such as norepinephrine, which bind to receptors on heart tissue. This action leads to an increase in both heart rate and the force of contraction, known as contractility.

By increasing heart rate, the sympathetic nervous system prepares the body for rapid responses to stress or emergency situations, ensuring that more blood is pumped throughout the body to deliver oxygen and nutrients to vital organs and muscles. Enhanced contractility further boosts the efficiency of the heart’s pumping action, allowing for greater blood flow.

Understanding this mechanism is key for recognizing how physiological responses are coordinated during times of stress or physical exertion, thus highlighting the importance of the sympathetic nervous system in maintaining adequate cardiovascular performance.