homeostasis & response

• homeostasis describes all of the processes that happen in a cell or organism to maintain conditions optimal
• homeostasis is needed to respond to changes in the internal and external environment
• because humans are organisms that live in a changing environment, we must regulate our body's internal conditions to make sure our enzymes and cells function well
• if conditions are not optimal, then our enzymes can denature, which reduces their ability to catalyse metabolic reactions
• humans must regulate their body's internal conditions to make sure that enzymes and cells function well
• the conditions that need to be regulated are internal body temperature, urea concentration, water levels, blood sugar levels, carbon dioxide levels
• control systems use both nervous and chemical responses
• control systems are made up of receptors, coordination centres, and effectors
• receptor cells detect changes in the environment
• coordination centres receive and process information arriving from receptor cells
• effectors (muscles or glands) carry out responses to stimuli that help to restore optimum levels
• negative feedback is the process that responds to changes in internal conditions away from the optimum and returns these conditions to their optimal range
• when our internal condition are optimal, the body does not need to respond, but if an internal condition changes and is no longer optimal, the body detects this change using receptors
• after a change has been detected, the body works to counteract the change, and the change is reversed and conditions are returned to the optimum