Question

Take notes from the following to explain homeostasis and how negative feedback are essential to maintaining homeostasis. Write notes from the below reading in 6 label sentences in a 6th grader’s response


READING.

Your cells, tissues, organs, organ
systems---yep we just leveled up those biological levels of organization---they're all working towards something called homeostasis. It's a state of balance.
Yes, homeostasis means many things in your
body: for example, that your blood stays within a certain pH level range.
It means your blood glucose remains within a certain range. It means your internal body temperature stays within a certain range.
See, we've mentioned the major body systems before, and that they work together---and today we're going to talk about HOW they work together---using something called positive and negative feedback. And, also, how this relates to homeostasis.

Ectotherm Regulating temperature
Debbie loved her heat lamp.
She would sit under the heat lamp on her rock. And when she got too hot, she would get off her rock and out of the heat lamp range and
go somewhere else.
So many years ago, I had a pet bearded dragon.
Her name was Debbie and she was the best lizard ever.
Debbie used to sit on our couch with me when
I'd watch TV.
And she loved to have her chin scratched
Debbie to be a happy lizard, so she could find an ideal temperature.
Well why all this talk about Debbie?
Well, Debbie is an example of an animal that
some people refer to as cold-blooded.
Or a fancier term, ectotherm.
We actually like the fancier term a bit better though, because her blood isn't necessarily
cold.
Her body temperature can fluctuate with the environment

But not you.

Endotherm Regulating temperature

You are warm-blooded, or the fancier term, an endotherm.
Your body works hard to keep the internal temperature it keeps.
It's also a beautiful example of something
called negative feedback.
Before we define it---let us show you this example.
Say you are in an environment that is very hot.

Like...being outside in the Texas summer heat.
That's typically hot.
Thanks to nerves which can act as sensors, the brain notices this.
It will send signals to counteract this variable.
Sweat glands do what they do best: sweat!
Heat is lost as that sweat evaporates off of your skin.
You may have some redness too---that's because of your blood vessels are getting wider (dilating) ---in order to help get rid of that heat.
The result, whether you realize it or not,
helps you lower your body temperature.
But wait!
What if you now go inside and the AC is blasting.
You will stop sweating.
You may even shiver.
The muscle contractions of shivering can generate heat.

And those blood vessels will now decrease
in diameter size (constrict) to help you conserve
the heat because that makes it harder for heat to escape.
Your body temperature can increase then.
This is negative feedback.
So a simplified definition: negative feedback
is when some variable triggers a counteracting

NEGATIVE Feedback Defined
response---in order to come back to some set point.
If we consider that this whole thing is actually
a negative feedback loop, we can see that
the negative feedback brings the body back
to the set point, which in this case, is a
stable temperature. Keeping homeostasis.

Regulating Blood Sugar

Negative feedback is also going on in the regulation of your glucose (your blood sugar).
Ok we're really simplifiying this here,
as we often do, but when glucose (blood sugar)
is too high, one hormone that is released is insulin.
I always imagine insulin as this hormone that
makes the cells say, "FEED ME!" because
it has the ability to make cells take in glucose.

On the flip side, if glucose is too low in
the blood, a hormone called glucagon can be
released. This hormone can have many effects and one of them is that it can cause the liver to release glucose into the blood.
There's more to the regulation of blood
sugar than this but you can see how that's
negative feedback---you have counteracting
responses here in order to keep homeostasis.

Answer 1

1. Homeostasis is your body keeping things steady, like temperature, blood sugar, and pH.
2. Cells, tissues, organs, and organ systems all work together to help keep homeostasis.
3. Some animals, like my bearded dragon Debbie, are ectotherms and change places to get warmer or cooler.
4. Humans are endotherms and use negative feedback to control temperature, for example sweating to cool down and shivering to warm up.
5. Negative feedback is when a change makes the body do the opposite thing to return to a set point, like blood vessels widening to lose heat or narrowing to keep heat.
6. Negative feedback also controls blood sugar: insulin helps cells take in glucose when it is too high, and glucagon makes the liver release glucose when it is too low.