fight or flight response

Which 2 systems are activated in a fight or flight response?

hormonal system

sympathetic nervous system

fight or flight response

-nerve impulses from sensory neurone is transmitted to the hypothalamus

-The hypothalamus activates the sympathetic nervous system

-The sympathetic nervous system activates the adrenal medulla to release adrenaline and noradrenaline into the bloodstream→ increases heart rate etc

-The hypothalamus also activates the hormonal system

-the hypothalamus stimulates the pituitary gland to release ACTH into the bloodstream

-ACTH stimulates the adrenal cortex to release steroid hormones such as cortisol

physiological responses in the fight or flight response [explain purpose]

increases heart rate

→increases blood flow to muscles (heart, brain, lungs etc)

→delivers more oxygen and glucose to muscles for respiration

pupils dilate

→allows more light into the eye→ this improves vision to detect danger

smooth muscle in airways relax [airways become wider]

→ allows more oxygen to enter the lungs

glycogen is converted into glucose via glycogenolysis

→increases blood glucose concentration

→more glucose is available for respiration, producing ATP for muscle contraction

arterioles in skin constrict

→reduces blood flow to skin

→blood diverted from skin to muscles (heart, brain, lungs etc)

Erector pili muscles contract

→hair stands up→ makes animal look larger and more aggressive

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