homeostasis and negative feedback 4.0 / 5 based on 2 ratings ? BiologyHealth, illness and diseaseA2/A-levelAQA Created by: EmmaCreated on: 03-04-13 17:13 deffinition and role of hormones 'chemical coordination', produced by endoctrine glands, transported in blood, target organs have specific receptor proteins 1 of 15 difference between nerve impulses and homones nerve impulses travel to specific parts of the body BUT hormones travel everywhere, only target cells respond 2 of 15 deffinion of homeostasis the mechanism that maintains a constant internal environment 3 of 15 why is homeostasis important? reactions are controlled by enzymes which could become denatured, osmotic problems, independence from external factors 4 of 15 deffinition of negative feedback a significant change from a set point or level that brings mechanisms to return to level 5 of 15 stages of control set point, receptor, controller, effector, feedback loop 6 of 15 deffinition of endotherms mammals, birds- rely on physicological means 7 of 15 deffinition of ectotherms reptiles, insects- rely on behavioural means 8 of 15 deffinition of convection due to movement of molecules - ie fluids 9 of 15 deffinition of conduction between molecules 10 of 15 deffinition of radiation emission of electromagnetic waves by a body 11 of 15 role of the hypothalomus the thermoregulatory centre, a controller, regulates heat loss and heat gain 12 of 15 heat loss: vasodilation, decreased metabolic rate, sweating, brown fat 13 of 15 heat gain: conservation- vasoconstriction, haising hairs // heat gain- increased metabolic rate, shivering, brown fat 14 of 15 positive feedback: results in greater departure from the original levels- eg. hypothermia- assocciated with the breakdown of control systems 15 of 15
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