Glossary
negative feedback
Negative feedback is a loop in which the response reverses the change that triggered it, bringing the value back toward its set point.
Negative feedback is the loop that keeps a value steady by reversing whatever moved it. A receptor detects the change, a control center compares the reading with the set point, and an effector acts to undo the change — and because the action removes the signal that started it, the loop settles. Body temperature works this way: a rise triggers sweating and widened vessels in the skin, both of which lose heat, and the temperature comes down until the trigger is gone. Blood glucose works this way in both directions, with insulin lowering a high reading and glucagon raising a low one. The name describes the direction and not a judgment: the response opposes the input. Most of the body's loops are negative feedback, because most of its jobs are holding something steady rather than finishing it.
Taught in
Related terms
- positive feedback — Positive feedback is a loop in which the response amplifies the change that triggered it, so a process runs to a finish instead of settling.
- receptor — A receptor is the structure that detects a change — the sensor of a feedback loop, reporting temperature, pressure, chemistry or stretch.
- effector — An effector is what carries out a feedback loop's response — a muscle that contracts or a gland that secretes.
- homeostasis — Homeostasis is the maintenance of a stable internal environment while conditions outside the body change — a loop that keeps correcting, not a fixed state.
Source: The anatomy and physiology guide in this course, whose organ and tissue descriptions follow the US National Cancer Institute's SEER Training Modules and MedlinePlus consumer health pages. Both are US federal government material, not subject to copyright in the United States. The definition above is written for this course in our own words. (SEER Training Modules accessed 2026-10-26; definition written 2026-10-27)