The sympathetic nervous system activates the body's fight or flight response. When stimulated, it causes an increase in heart rate, among other effects. This helps prepare the body for action in stressful or dangerous situations. The sympathetic pathways travel from the spinal cord to the heart and release norepinephrine as a neurotransmitter at the cardiac synapses. Norepinephrine bi... https://www.newsstatix.com/cardiac-autonomic-control-market-size-share-analysis-2023-2030/