Sympathomedullary Pathway (SAM Pathway)
The sympathomedullary pathway (SAM pathway) is the route through which the brain directs the sympathetic branch of the autonomic nervous system (ANS) to activate in response to short-term stress. The hypothalamus activates the sympathetic branch of the ANS, which then signals the adrenal medulla to secrete adrenaline and noradrenaline. The sympathetic nervous system itself has direct connections to the heart and activation speeds up heart rate and raises blood pressure. These effects are increased and sustained by the release of adrenaline and noradrenaline. The end result is that oxygen is rapidly pumped to the muscles allowing for increased physical activity. As a result of all this the person is ready for ‘fight or flight’.