Adrenaline and noradrenaline are the fight and flight hormones and are secreted by the adrenal gland.
Both hormones show antagonistic effects and are responsible for the fight and flight response of the body.
Adrenaline initiates the stress responses in the body.
It mainly acts on smooth muscles, cardiac muscles, blood vessels, skeletal muscles and fat cells.
It increases heart rate, blood pressure, metabolic rate, dilates blood vessels and increases the breathing rate and hence oxygen consumption and glucogenesis (i.e. the formation of glucose by the breakdown of liver glycogen), elevating the blood glucose levels.