Which neurotransmisssion result is linked with the sympathetic nervous system?

The sympathetic nervous system plays a crucial role in the body's "fight or flight" response, which is activated during stressful situations. One of the key neurotransmitters involved in this system is norepinephrine, which is released from sympathetic nerve endings. When activated, the sympathetic nervous system triggers a range of physiological responses that prepare the body for action.

Increased heart rate is a vital response during sympathetic activation. This occurs because norepinephrine binds to beta-1 adrenergic receptors in the heart, leading to enhanced heart rate and contractility. This response is essential for ensuring that more blood, and therefore oxygen, is delivered to muscles and vital organs in critical situations.

Other options do not align with the typical effects of the sympathetic nervous system. For example, decreased contractility and vasodilation are more characteristic of the parasympathetic nervous system, which promotes a state of rest and relaxation. Similarly, decreased adrenaline would contradict the activation of the sympathetic nervous system, where increased levels of adrenaline (also known as epinephrine) are expected to support the heightened state of alertness and readiness for action.