Homeostasis and Feedback Mechanisms

If the environment gets cold, we will often shiver in order to:

• keep body temperature the same as the external temperature
• decrease body temperature
• increase body temperature
• regulate blood pressure

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NGSS.HS-LS1-3

The two types of feedback systems that help organisms maintain homeostasis are:

• positive and negative 
• receptor and effector
• static and dynamic
• minor and major

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NGSS.HS-LS1-3

Maintaining body temperature is an example of a:

• negative feedback loop
• positive feedback loop

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NGSS.HS-LS1-3

When glucose levels in the blood rise, your brain sends a signal to your pancreas. The pancreas releases insulin, which opens channels in cell membranes to allow glucose to enter the cell, lowering blood sugar levels. This is an example of a:

• Positive Feedback Loop

• Negative Feedback Loop

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NGSS.HS-LS1-3

Which of the following scenarios describes a positive feedback mechanism?

• After childbirth, high levels of prolactin induce lactation in the mother. During nursing, infant suckling triggers the release of more prolactin, which further stimulates lactation.

• After eating, blood glucose levels rise, stimulating the release of insulin from the pancreas. Insulin causes cells to uptake glucose from the blood, lowering blood glucose levels.

• several hours after a meal, blood glucose levels begin to drop, prompting the pancreas to secrete glucagon. Glucagon causes the liver to convert stored glycogen into glucose, raising blood glucose levels.

• During exercise, an increase in body temperature causes the body to produce sweat. As the sweat vaporizes, the body cools down due to evaporative cooling.

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NGSS.HS-LS1-3

In a negative feedback loop, what happens to a variable (like temperature) when it increases past its normal state?

• It continues to increase.

• It decreases until it resumes its normal state.

• It decreases until it is lower than its normal state.

• It does not change.

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NGSS.HS-LS1-3

Rapid growth during puberty causes your body to release more and more growth hormones. As you grow, more and more growth hormones are released until puberty is reached, and then the hormones stop.

• Positive feedback

• Negative feedback

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NGSS.HS-LS1-3

What is another word that can be used to describe "homeostasis"?

• equal

• complete

• stable

• correct

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NGSS.HS-LS1-3

What is the point of a feedback loop?

• To provide the body with more energy.

• To provide the body with more food.

• To make sure the conditions in the body are always changing.

• To make sure the conditions in the body remain stable.

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NGSS.HS-LS1-3

Negative feedback loops

• amplify processes

• prevent small changes from getting larger

• are initiated during childbirth

• are found only in plants

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NGSS.HS-LS1-3