+
Positive and Negative Feedback
Next Generation: HS.LS1.3 NGSS

Positive and Negative Feedback

Description:

This lesson will explain in detail positive feedback as a control mechanism of homeostasis.

(more)
See More
Try a College Course Free

Sophia’s self-paced online courses are a great way to save time and money as you earn credits eligible for transfer to over 2,000 colleges and universities.*

Begin Free Trial
No credit card required

25 Sophia partners guarantee credit transfer.

221 Institutions have accepted or given pre-approval for credit transfer.

* The American Council on Education's College Credit Recommendation Service (ACE Credit®) has evaluated and recommended college credit for 20 of Sophia’s online courses. More than 2,000 colleges and universities consider ACE CREDIT recommendations in determining the applicability to their course and degree programs.

Tutorial

What's Covered

Welcome to today’s lesson on negative and positive feedback. In this lesson today, you will learn about negative and positive feedback as a means of maintaining homeostasis in our body. Specifically, you will learn about:

  1. Overview of Homeostasis
  2. Negative Feedback
  3. Positive Feedback

1. Overview of Homeostasis

Homeostasis is just that maintenance of our internal environment and the internal environment is maintained by either negative or sometimes positive feedback.

Terms to Know

    • Homeostasis
    • The maintenance of the body’s internal environment.
    • Negative Feedback
    • A mechanism in which a change in the body is detected and then reversed to maintain homeostasis.
    • Positive Feedback
    • A mechanism in which a change in the body is detected and then intensified.

2. Negative Feedback

Negative feedback is the most common type of feedback that we experience and negative feedback will reverse a detected change.

Conditions in your extra cellular fluid might experience some sort of change. Maybe the pH changes, or the temperature changes, or the chemical makeup changes, and sensory receptors will detect that change. Then that change will be reversed in order to maintain homeostasis, so cells need to be in an environment that's relatively constant.

If the pH or temperature gets too high or too low, cells aren't going to be able to function properly, and then other body mechanisms aren't going to function properly as well. So it's really important that homeostasis is maintained.

Terms to Know

    • Sensory Receptor
    • Receptors that detect a stimulus or change in the body.
    • Integrator
    • The main integrator in the body is the brain. The integrator receives signals from sensory receptors and determines an appropriate response.
    • Effectors
    • Glands or muscles that carry out the response as designated by the integrator.

Take a look at the diagram below to see how negative feedback works to maintain homeostasis.

So first, your body will experience some sort of stimulus. Let's say you walk outside today and it's really hot outside. The stimulus would be the heat that you feel and you start to get really hot from being outside. Sensory receptors in your skin will detect that heat and send the information to the main integrator in your body, which is the brain.

Your brain will then interpret what needs to happen in order to lower your body temperature and then it'll send that information to effectors; which are glands or muscles. Those effectors will then carry out the response.

There are different mechanisms in order to cool down your body temperature, vasodilation is one mechanism. Vasodilation is when your blood vessels will widen and they do this in order to expel access heat. Effectors, muscles or glands, will work to carry out these responses such as vasodilation and sweating. When you sweat, the fluids that you sweat out will be evaporated off your body and then by being evaporate off your body, it allows your body temperature to cool. You might experience heavy breathing when you really hot, and when you're really hot, your muscle activity will also be reduced. These are all ways that your body temperature could be lowered.

Then from there, our response would be that our body temperature lowers, so you'll notice how the change that we first experienced, is reversed.


3. Positive Feedback

Positive feedback is more rare in our body, and it doesn't have a huge effect on homeostasis. When you're talking about homeostasis, you're talking about the maintenance of our extracellular fluids.

Positive feedback will detect a change, and rather than reversing it, it will actually intensify it.

IN CONTEXT

A common example is childbirth; in childbirth the fetus in the mother will exude pressure on the uterus. The uterus will then exude pressure on the fetus back and forth. This will keep intensifying until, finally, the fetus is expelled. Rather than that change reversing, it is actually being intensified.

Summary

So this lesson has been an overview on negative and positive feedback and the maintenance of homeostasis in our body.

Keep up the learning and have a great day!

Source: THIS WORK IS ADAPTED FROM SOPHIA AUTHOR AMANDA SODERLIND

TERMS TO KNOW
  • Homeostasis

    The maintenance of the body’s internal environment.

  • Negative Feedback

    A mechanism in which a change in the body is detected and then reversed to maintain homeostasis.

  • Positive Feedback

    A mechanism in which a change in the body is detected and then intensified.

  • Sensory Receptor

    Receptors that detect a stimulus or change in the body.

  • Integrator

    The main integrator in the body is the brain. The integrator receives signals from sensory receptors and determines an appropriate response.

  • Effectors

    Glands or muscles that carry out the response as designated by the integrator.