When an organism confronts any scary situation, adrenaline hormone is secreted from the adrenal gland and is poured directly into the blood which then circulates to various parts of the body, resulting into the following actions:
(i) The main target organ includes the heart which starts to beat faster. Due to which, more amount of oxygen is supplied to the muscles.
(ii) The blood supply to digestive system and the skin is reduced due to contraction of muscles around small arteries in these organs. This diverts the blond to the skeletal muscles.
(iii) The breathing rate also increases because of the contraction of the diaphragm and rib muscles.