homeostasis

  • Created by: aryan26
  • Created on: 06-02-19 19:47
View mindmap
  • 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
    • negative feedback
      • change detected by receptors= effectors stimulated to reduce/reverse the change
      • e.g. control of blood glucose levels by insulin and glucagon
  • heat loss
    • activated when temp of blood flowing through hypothalamus increases

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Health, illness and disease resources »