8/13/2019 1.1 Negative Feedback
1/11
Group 1:
1)Nadiah binti Yusof
2)Genevie Eleanor Ruby
3)Latifah binti Jalilul
4)Chai Siew Lian
5)Nurpaznin binti Jusoh
8/13/2019 1.1 Negative Feedback
2/11
Negative Feedback
8/13/2019 1.1 Negative Feedback
3/11
Overview of Negative FeedbackIn animals such as ourselves, the internal
environment of our bodies must have certainconditions within tolerable limits to continue the
healthy functioning of us.
This is done by a process called negativefeedback control, where various receptors and
effectors bring about a reaction to ensure thatsuch conditions remain favourable.
8/13/2019 1.1 Negative Feedback
4/11
Definition of Negative Feedback
The mechanism by which the body maintains
conditions within particular limits. The body willdo this by opposing a change that deviates from
the normal
8/13/2019 1.1 Negative Feedback
5/11
The Principle of Negative Feedback
Control
8/13/2019 1.1 Negative Feedback
6/11
Examples of Negative FeedbackControl
Regulation of body temperature
Regulation of blood sugar
Regulation of blood pressure
8/13/2019 1.1 Negative Feedback
7/11
Glucose is important for healthy functioning becauseit is required for the formation of ATP, the molecule ofenergy transfer in our bodies.
Two important hormones for blood glucose regulationare insulin and glucagon.
Insulin is secreted by beta cells while alpha cellssecrete glucagon. As the food we eat is broken down,our blood sugar rises due to the carbohydrates. Inorder to avoid serious problems such as kidney andcardiovascular damage, blood sugar levels have to bedecreased.
Mechanism of Blood Sugar
Regulation
8/13/2019 1.1 Negative Feedback
8/11
So, how does our body regulate our
blood glucose levels to maintainhomeostasis?
8/13/2019 1.1 Negative Feedback
9/11
Mechanism of Blood Sugar Regulation
8/13/2019 1.1 Negative Feedback
10/11
The internal mechanism for blood glucose regulation
is negative feedback.
As you can see from the figure, depending on
whether glucose levels are rising or falling, the body
has a different response.
When levels increase, the beta cells secrete insulin
which then converts glucose to glycogen so that
extra glucose can be stored restoring glucose levels
to a normal level. When levels fall, the alpha cells secrete glucagon
which converts stored glycogen to glucose
increasing levels back to normal.
8/13/2019 1.1 Negative Feedback
11/11
Benefits of Negative Feedback
Homeostasis has survival value because itmeans an animal can adapt to a changingenvironment. It can deal with the temperaturedifference you face when you step out your frontdoor.
The body will attempt to maintain a norm, thedesired level of a factor to achieve homeostasis.However, it can only work within tolerable limits,where extreme conditions can disable thenegative feedback mechanism