How does the sympathetic nervous system influence blood pressure?

The sympathetic nervous system primarily influences blood pressure by activating the "fight or flight" response, which is crucial during stressful situations. When it is stimulated, it increases heart rate and enhances the force of heart contractions, thereby elevating cardiac output. Additionally, this system causes the constriction of blood vessels, which leads to increased vascular resistance. Together, these actions result in a significant rise in blood pressure.

This response is critical for ensuring that adequate blood flow reaches vital organs during times of stress or danger. The increase in heart rate and blood vessel constriction is mediated by neurotransmitters such as norepinephrine, which bind to receptors that promote these effects. Hence, the correct characterization of the sympathetic nervous system’s role in blood pressure regulation highlights its ability to increase both heart rate and vascular resistance, making the blood pressure rise as needed.