How do the fast and the slow stress responses differ? · Grey Matter

The fast response is nervous: within seconds the sympathetic system drives the adrenal medulla to release adrenaline, and with noradrenaline from sympathetic nerves it raises heart rate, blood glucose and alertness, fading within minutes.

How do the fast and the slow stress responses differ?

The fast response is nervous: within seconds the sympathetic system drives the adrenal medulla to release adrenaline, and with noradrenaline from sympathetic nerves it raises heart rate, blood glucose and alertness, fading within minutes. The slow response is hormonal: the hypothalamus releases CRH, the pituitary releases ACTH, and the adrenal cortex makes cortisol, which peaks some tens of minutes after the event. Cortisol is a steroid that enters cells and changes gene expression, so its effects last hours, and it ends the response by feeding back on the hypothalamus and pituitary. The first prepares for action now, the second reorganises metabolism, immunity and the brain for what follows.