explanation of physiological changes in the stress response

heart rate increase

• allows more aerobic respiration for increased ATP

arterioles to digestive system are constricted

• less blood travels to the gut, where its not needed as much

blood glucose levels rise

• glycogen is broken down and released from the liver

endorphins are released in brain

• natural painkillers allow the body to push beyond normal limits

ventilation rate and depth increase

• more oxygen is taken in to be used in aerobic respiration

erector pili muscles

• hairs are raised on end, evolutionary adaptation to frighten an enemy

metabolic rate increases

• increased respiration releases ATP, more glycogenolysis occurs

sweat production increases

• prevents body overheating when exercise level increases

sweat production increases

prevents body overheating when exercise level increases

defaecation and urination may occur

• may deter predators and decreased body weight allows faster movement

pupils dilate

allows in more light, gives better image of threatening situation