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A Level Biology: Homeostasis 3 – Blood Sugar
Hi! Welcome to the third of our videos on Homeostasis. Today, we are going to be looking
at Blood sugar regulation.
Glucose is a very important compound as it is needed by body cells for respiration. Once
we’ve digested our food, our blood sugar level increases. What then happens, because
of that, the pancreas produces a hormone called insulin. Insulin then enters the blood stream
and what that does is it allows the body cells to take up glucose which is needed for respiration.
Any excess glucose is then converted to glycogen by the liver. Therefore, blood glucose gets
reduced.
If blood sugar is too low, say you had a period of fasting then the pancreas stops producing
insulin. What this does, it just means that less glucose is absorbed by the cells and
therefore, blood glucose increases. What also happens is the pancreas also produces another
hormone called glucagon. What this does is it tells the liver to convert glycogen back
into glucose. It does this because glycogen is just a polymer chain. It is very similar
to starch. What happens is you got your individual monomer units which are glucose molecules
and these are broken off one at a time and released back into the blood stream.
Here, we’ve got our negative feedback loop. Here, you can see just what controls are regulated
plus blood sugar. So you can see that if we have an increase in blood sugar levels, the
pancreas makes insulin, the blood then transports insulin to our body where it is picked up
by the body cells and also the liver where it is converted to glycogen, therefore reducing
blood sugar. If it is too low, the pancreas stops making insulin and starts to make glucagon
instead. Glucagon is transported around the body and the liver is where glycogen is converted
back into glucose and put back into the blood stream which overall raises blood sugar levels.
If this feedback system doesn’t work properly, it can lead to conditions such as diabetes
and also hyperglycemia, which is high blood sugar and hypoglycemia which is low blood
sugar.
That concludes the short presentation. I hoped you enjoyed it. Don’t forget to keep a lookout
for some more videos coming out soon.
[end of audio – 03:06] A Level Biology: Homeostasis 3 – Blood Sugar
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