Negative and Positive Feedback Loops

Negative Feedback

Negative feedback is an important type of control that is found in homeostasis. A negative feedback control system responds when conditions change from the ideal or set point and returns conditions to this set point.

Direction of compensation is opposite to direction of disturbance.

To regulate these things the body needs firstly to detect the level then to respond in an appropriate way.

 For temperature, water and glucose there is a level called the 'norm' (e.g, normal body temperature is 36.9°C).
If the level gets too high this triggers the body to lower it. If the level gets too low this triggers the body to raise it. This is the principle of negative feedback.



Examples;

• Control of Blood pressure
• Blood Sugar concentration
• Heat response
• Cold Response

Positive Feedback

Compensation INCREASES the level of disturbance = amplified response.
Positive feedback is when a high level of something triggers the body to increase it even further

Neuron Membrane depolarization: A typical positive feedback response

- Emptying of body cavities (defecation, urination, birth, ejaculation)
- Filing of Body cavities
- Sexual Behaviour
- Muscle

Feedforward

Feedforward information serves to alter the set point in regulatory systems. An examples might be changes in set point due to acclimation.



SOME SYSTEMS NEED BOTH POSITIVE AND NEGATIVE FEEDBACK RESPONSES


for example the Human Ovarian and Uterine Cycles
the cycle that women go through,  systems within the body are constantly changing meaning the maintaining levels of Estragon are having to keep changing, therefore both responses are needed


Overall....
All control Systems require:
A sensor
A reaction mechanism (integrator and effector)
Communication system (E.g. hormones)



@Science_nerd101 (Twitter)