Lecture Eight Homeostasis Homeostasis Homeostasis is all about

Lecture Eight Homeostasis

Homeostasis • Homeostasis is all about balancing inputs (stuff going into your body) with outputs to maintain a constant internal environment • The conditions inside your body need to be kept steady, even when the external environment changes. This is important because your cells need the right conditions in order to function properly. • You have loads of automatic control systems e. g. nervous and hormonal. There`s a control system that maintains your water content and body temperature • All your automatic control systems are made up of three main components; receptors, processing centres and effectors.

Negative feedback counteracts changes Your automatic control systems keep your internal environment stable using a mechanism called negative feedback. If the level of something in your body gets too high or low (water or temperature) your body uses negative feedback to bring it back to normal Step one – Receptor detects a change in the environment, level is high. Step two – The processing centre receives the information and coordinates a response. Step three – Effector produces a response which counteracts the change, the level decreases This then leads on to….

Negative feedback counteracts changes Step One – Receptor detects a change in the environment, level is low. Step Two – The processing centre receives the information and coordinates a response. Step Three – Effector produces a response which counteracts the change, the level increases. This leads back to the previous three steps. The effectors will continue producing the responses as long as they are stimulated by the processing centre. The process is all automatic.

Quiz Time !! What does homeostasis mean? Why do the conditions in your body need to be kept steady? Name two automatic control systems in your body. What are three main components working together to keep a steady condition? What is meant by the term “negative feedback”? Outline the diagram of how the three main components counteract changes. How long will the effectors continue producing responses?