Final answer:
Epinephrine acts rapidly to prepare the body for a fight-or-flight response by increasing blood glucose and oxygen supply, elevating heart and respiratory rates, and directing blood flow towards vital organs.
Step-by-step explanation:
Epinephrine, whether made by the body or by a drug manufacturer, works rapidly to increase blood glucose levels, enhance heart rate and respiratory rate, and redirect blood flow to essential organs. This action prepares the body for a 'fight-or-flight' response by increasing the blood supply to organs like the heart, brain, and skeletal muscles while constricting blood vessels to non-essential systems like the digestive and renal systems during moments of acute stress.
In addition to the immediate cardiovascular effects, epinephrine helps in the breakdown of glycogen stores, leading to an increase in blood glucose levels, which provides the required energy for muscles during stressful situations. It also facilitates increased oxygen supply to cells by dilating the bronchioles.