Homeostasis: The maintenance of a stable internal environment within narrow limits despite changes in external conditions.
Negative feedback: A control mechanism in which a change in a variable triggers a response that reverses that change, returning it towards the set point.
Set point: The target value around which a controlled variable is kept by homeostatic mechanisms.
Effector: A structure (such as a muscle or gland) that carries out the corrective response directed by the control centre.
Antagonistic hormones: A pair of hormones with opposite effects, such as insulin and glucagon, allowing precise two-way control.
Insulin: A hormone from pancreatic β cells that lowers blood glucose by promoting glucose uptake and storage as glycogen.
Glucagon: A hormone from pancreatic α cells that raises blood glucose by stimulating breakdown of glycogen in the liver.
Osmoregulation: The homeostatic control of the water and solute balance of body fluids, carried out chiefly by the kidney.