HOMEOSTASIS

Question 1

homeostasis

Answer 1

maintenance of a constant internal environment

Question 2

factors to be maintained (4)

Answer 2

• glucose concentration
• pH
• core temperature
• solute potential

Question 3

how is dynamic equilibrium kept?

Answer 3

• negative feedback

Question 4

negative feedback

Answer 4

• moving back to equilibirum

Question 5

steps of negative feedback (6)

Answer 5

• set point - the norm
• input - change to the system
• receptor - measures level of new factor
• co-ordinator - information stored here to co-ordinate effectors
• effectors - bring about change to return to set point
• output - corrective procedures

Question 6

negative feedback in the body (2)

Answer 6

• glucose concentration - too high, release insulin, too low, glucagon released to convert glycogen to glucose
• temperature, too high, vasodilation, sweat, behaviour (take off clothes), too low, vasoconstrict, shiver, hair stands on end

Question 7

positive feedback

Answer 7

• intensifying a change

Question 8

positive feedback in the body (2)

Answer 8

• pregnancy, oxytocin stimulates contraction of uterus, contraction stimulates production of oxytocin
• when a person is cut platelets adhere to wound, secreting signalling molecules attracting more platelets