Topic overview

Start with the big picture

Homeostatic systems detect changes in regulated variables such as temperature, blood glucose, blood pressure, and pH. A sensor sends information to a control center, which compares the sensed value with a set point and directs an effector response. Negative feedback counteracts deviations and is the main mechanism for maintaining stability; positive feedback amplifies change and requires a means of termination. Regulation also varies in timing and flexibility: nervous responses are generally rapid, endocrine responses more sustained, and set points may shift with conditions such as fever or acclimatization. The lesson connects these principles to examples including the baroreceptor reflex and thermoregulation, and considers how disrupted homeostasis relates to disease.