Homeostasis 5.0 / 5 based on 2 ratings ? BiologyHomeostasisA2/A-levelAQA Created by: natalie1421Created on: 20-04-17 11:41 What is homeostasis? The maintenance of a constant internal environment despite external changes 1 of 9 Give 4 things that need to be maintained in humans Body temperature, pH, blood glucose concentration, water potential of the blood 2 of 9 What is negative feedback? The reversing of a change in the internal environment, bringing the level back to normal 3 of 9 Outline the negative feedback pathway Stimulus - Receptor - Communication pathway - Effector - Response 4 of 9 Give an an example of a stimulus for negative feedback Low blood temperature/high blood glucose concentration etc. 5 of 9 What is positive feedback? When the original change in internal environment is increased, bring the level further away from normal 6 of 9 Give an example of positive feedback Hypothermia- When the body temperature falls, enzyme activity decreases causing a further drop in body temperature 7 of 9 What systems are involved in signalling a change in internal environment to other cells? Nervous system and endocrine system 8 of 9 Outline the positive feedback pathway Change away from optimum/stimulus - Receptor - Communication pathway - Effector - Change away from optimum 9 of 9
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