Adrenaline is the common name for Epinephrine. It occurs natuarlly in the body and is vital to life.
It is a Central Nervous System stimulant, it speeds up heart rate, breathing rate, constricts (shrinks) Peripheral blood vessels and Dilates(enlarges) central blood vessels.
WHen you get Scared, startled, or in a fight epinephrine AKA adrenaline is released and makes all the blood vessel's close to skin shrink for a variety of reasons, to reduce blood loss if injured because the vessels are smaller so less blood can flow thru them to leak out, it also causes blood to be diverted to heart, lungs and large muscles to aid in the "fight or flight" response. Muscles get more blood to "fight or flight" depending on your choice, heart speeds up to circulate more blood and therefore more oxygen to the heart lungs and muscles to either get you away from the threat by the "flight" response or keep muscles well oxygenated for the "Fight" response..
Im sure if you google Epinephrine or adrenaline, you can find what u need.
In answer to the question of "harm" to organs... yes and no. large doses will cause your heart to beat too fast and depending on the health of the heart could cause a heart attack. Interestingly enough when someone has a heart attack that causes the heart to stop beating, we give epinephrine to try to stimulate it to pump again... but we only give 1milligram thru the IV up to a maximum of 10milligrams in 1 milligram doses., for severe anaphalactic (allergic) reactions we only give 0.3milligrams injected into the fat just under the skin.
17 years emergency medicine.