5.5.8 coordinating responses

Question 1

physiological changes associated with the fight or flight response:
survival value of

Answer 1

• pupils dilate
• heart rate & blood pressure increase
• arterioles to digestive system & skin constrict (vasoconstriction) whilst those to muscles & liver dilate (vasodilation)
• blood glucose levels increase
• metabolic rate increases
• erector pili muscles in skin contract
• ventilation rate & depth increases
• endorphins released in brain (natural painkillers)

Question 2

physiological changes associated with the fight or flight response:
survival value of pupils dilating

Answer 2

allows more light to enter eyes = makes retina more sensitive

Question 3

physiological changes associated with the fight or flight response:
survival value of HR & blood pressure increase

Answer 3

increases rate of blood flow to deliver more oxygen/glucose to muscles & remove more carbon dioxide/other toxins

Question 4

physiological changes associated with the fight or flight response:
survival value of vasodilation of arterioles to muscle/liver & vasoconstriction of arterioles to digestive system/skin

Answer 4

diverts blood flow awa from skin/digestive system & towards muscles

Question 5

physiological changes associated with the fight or flight response:
survival value of increase in blood glucose levels

Answer 5

supplies energy for muscular contraction

Question 6

physiological changes associated with the fight or flight response:
survival value of increase in metabolic rate

Answer 6

converts glucose to useable forms of energy (eg. ATP)

Question 7

physiological changes associated with the fight or flight response:
survival value of erector pili muscles in skin contracting

Answer 7

makes hairs stand up = sign of aggression

Question 8

physiological changes associated with the fight or flight response:
survival value of ventilation rate & depth increasing

Answer 8

increases gaseous exchange so more oxygen enters blood & supplies aerobic respiration

Question 9

physiological changes associated with the fight or flight response:
survival value of endorphins being released in the brain

Answer 9

wounds inflicted on mammal don’t prevent activity

Question 10

outline the coordination of the fight or flight response

Answer 10

1. inputs feed into sensory centres in cerebrum
2. cerebrum passes signals to association centres
3. if threat is recognised, cerebrum stimulates hypothalamus
4. hypothalamus increases activity in sympathetic nervous system & stimulates release from hormones from anterior pituitary gland

Question 11

examples of hormones released from anterior pituitary gland (fight or flight response)

Answer 11

• hypothalamus secretes releasing factors into blood
• pass down portal vessel into pituitary gland & stimulate release of tropic hormones from anterior pituitary gland
• eg. CRH, ACTH, TRH

Question 12

role of CRH

Answer 12

• released from hypothalamus (releasing factor) & stimulates release of ACTH from anterior pituitary gland
• ACTH passes around blood & stimulates adrenal cortex to release many different hormones (eg. glucocorticoids such as cortisol)

Question 13

role of TRH

Answer 13

• causes release of TSH
• TSH stimulates thyroid gland to release more thyroxine

Question 14

what does the sympathetic nervous system stimulate

Answer 14

= adrenal medulla

• adrenaline released

Question 15

what is adrenaline also known as

Answer 15

the first messenger

Question 16

outline the mechanism of adrenaline action

Answer 16

1. adrenaline binds to adrenaline receptor on plasma membrane
   - receptor associated with G protein on inner surface of plasma membrane
   - G protein stimulated to activate enzyme adenyl cyclase
2. adenyl cyclase converts ATP to cyclic AMP (cAMP) = second messenger inside cell
3. cAMP causes an effect inside cell by activating enzyme action
   - precise effect depends upon cell that adrenaline has bound to