Negative Feedback
The primary mechanism that maintains homeostasis.
Negative feedback
Organ that detects high blood glucose and releases insulin.
Pancreas.
Device used to explain negative feedback in a house.
Thermostat.
Part of the brain that regulates body temperature.
Hypothalamus.
When homeostasis fails, the result is often...
illness
Two required components of a negative feedback mechanism.
Senor and control center.
Hormone released when blood glucose is too high.
Insulin
Desired temperature set on a thermostat.
Set point
Blood vessels do this when body temperature is too low.
Constrict (vasoconstriction)
Disease caused when the pancreas cannot produce enough insulin.
Diabetes mellitus
What happens to the original stimulus during negative feedback?
It is reduced or dampened.
Insulin causes body cells to do what with glucose?
Take up glucose from the blood
The thermostat detects temperature using this component.
Senor (thermometer)
Muscle activity that generates heat when you're cold.
Shivering
Sweat lowers body temperature by this process
Evaporation
What happens to the control center once normal conditions are restored?
It is no longer activated.
Why does insulin secretion stop after blood glucose returns to normal?
The stimulus (high blood glucose) has been removed.
Explain why room temperature fluctuates slightly around the set point.
The furnace turns on when the room is too cold and off when it's too warm, causing small fluctuations above and below the set point.
Compare the body's responses to being too cold versus too hot.
Too cold: Vasoconstriction and shivering conserve and generate heat. Too hot: Vasodilation and sweating increase heat loss.
Name the sensor and control center in body temperature regulation.
The hypothalamus acts as the control center and detects changes in core body temperature.
Explain the sequence of a negative feedback loop.
A stimulus changes the internal environment → the sensor detects the change → the control center activates effectors → the response opposes the original change → normal conditions are restored → the response stops.
Explain how insulin maintains homeostasis.
High blood glucose stimulates the pancreas to release insulin. Insulin causes cells to absorb glucose, lowering blood glucose back to normal. Once normal levels are reached, insulin secretion decreases.
Compare the thermostat in a house with homeostasis in the human body.
Both have a set point, a sensor to detect changes, a control center to initiate a response, and effectors that return conditions to normal by reducing the original stimulus.
Explain how body temperature returns to normal after becoming too high.
The hypothalamus detects increased temperature, blood vessels in the skin dilate, sweat glands produce sweat, evaporation removes heat, and body temperature gradually returns to about 37°C (98.6°F).
Explain why negative feedback is essential for survival.
Negative feedback prevents internal conditions from moving too far from normal, allowing body temperature, blood glucose, pH, and other internal conditions to remain within the narrow ranges necessary for cells to function properly.