Unit 14: Homeostasis and Feedback Loops
How the body senses when something is off balance and pulls it back -- or, in labor and clotting, pushes it further.
4 topics · 12 questions
Each topic is a path, not a menu: work down it in order and every question builds on the one above. Click any of them to watch the answer draw itself.
What Homeostasis Actually Means
- How it worksHow do sensors, a control center, and effectors work together to keep an internal condition stable?
- Common mistakeWhy isn't homeostasis about keeping a condition perfectly constant with zero fluctuation at all?
- Going furtherWhat happens to a body's internal stability when one of its feedback systems fails?
Your turn1 of 2
Whether you're standing in snow or walking through a desert, your internal body temperature stays remarkably close to 37 degrees Celsius. Why does your body temperature stay this stable across such different environments?Negative Feedback
- How it worksWalk me through how a thermostat's negative feedback loop senses temperature and shuts the heater off automatically.
- Common mistakeWhy doesn't negative feedback mean something bad is happening inside the system?
- Ties togetherHow does your body's response to overheating mirror a thermostat's negative feedback loop?
Your turn1 of 2
A house's thermostat is set to a target temperature, and the heater clicks off automatically the instant a room reaches that temperature. Why does the heater turn off the moment the target temperature is reached?Positive Feedback
- How it worksHow does a positive feedback loop amplify a signal further away from a starting point instead of restoring it?
- Common mistakeWhy doesn't positive feedback keep running forever without ever being switched off?
- Ties togetherHow does blood clotting use positive feedback to rapidly seal a wound once it starts?
Your turn1 of 2
Unlike a thermostat correcting back toward a set point, labor contractions during childbirth get progressively stronger and more frequent as delivery approaches. Why do contractions get stronger and stronger instead of leveling off?How Body Systems Cooperate to Maintain Balance
- How it worksHow does the nervous system coordinate signals across multiple organ systems during physical exertion?
- Going furtherWhat happens to overall homeostasis when one organ system can't keep up with the demands of the others?
- Ties togetherHow do the circulatory, respiratory, and excretory systems each play a different role in maintaining homeostasis?
Your turn1 of 2
A hard sprint causes your heart rate, breathing rate, and sweating to all increase at nearly the same moment, even though they involve completely different organs. Why does a hard sprint speed up your heart, lungs, and sweat glands all at once?