Feedback

• Insulin Receptor (hormone receptor): Found on many cell surfaces, e.g. muscle, liver, Insulin binding causes glucose transporter proteins to be placed in cell membranes so more glucose enters cell; membrane is more permeable
• Drugs: Beta-blockers bind to beta-adrenoreceptors on cardiac and vascular smooth muscle cells, they block the receptors which bind to adrenaline which raises heart rate; heart rate is therefore steady
• Homeostasis: Maintenance of a constant internal environment despite external changes; physiological factors controlled in mammals: body temperature, blood glucose, salt, water potential, pressure and tissue CO_2 concentration
• Negative Feedback: Reverse any change in internal environment condition in 3 steps, ensuring return and maintenance of optimal state: Change detected (stimulus) -> Change is signalled to other cells -> Response occurs to reverse change