homeostasis
- Created by: aryan26
- Created on: 06-02-19 19:47
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- homeostasis
- uses chemical and electrical systems to monitor and respond to changes
- info transmitted to the brain via impulses sent along motor neurones to effectors
- sensory receptors detect internal and external changes
- positive feedback
- change detected by receptors= effectors stimulated to reinforce the change
- e.g. blood clotting,childbirth
- thermoregulation in ectotherms
- depends on: exothermic reactions latent heat evaporation radiation convection condction
- use surroundings to warm up- core body temp dependent on environment
- those in water may not need to thermoregulate
- high heat capacity so temp doesn't change much
- behavioural responses: basking, conduction, seek shade
- physiological responses: dark colours, can alter heart rate
- more vulnerable to fluctuations in external temp
- thermoregulation in endotherms
- e.g. mammals and birds
- metabolic processes warm them up- maintain stable core temp despite environmental changes
- adaptations
- detection: peripheral receptors detect surface changes
- receptors in hypothalamus detect temp of blood
- temp of skin more likely to be effected by external conditions- allows to predict possible problems
- becoming dormant/hibernation
- humans: clothes housing
- rely on physiological adaptations
- peripheral receptors, thermoregulatory centres
- vasodilation- arteriovenus shunt vessels constrict=forces blood through capillary systems. skin flushes, cools via radiation
- vasoconstriction
- increased/decreased sweating
- shivering- metabolic heat from exothermic reactions
- erector pili muscles relax/contract
- anatomical adaptations- large SA:V
- two control centres
- heat loss
- activated when temp of blood flowing through hypothalamus increases
- heat gain
- activated when temp of blood flowing through hypothalamus decreases
- sends impulse through autonomic NS to effectors in skin and muscles
- heat loss
- negative feedback
- change detected by receptors= effectors stimulated to reduce/reverse the change
- e.g. control of blood glucose levels by insulin and glucagon
- uses chemical and electrical systems to monitor and respond to changes
- heat loss
- activated when temp of blood flowing through hypothalamus increases
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