From terpenes to steroids part 2: squalene, cholesterol, and steroids

After learning about terpenes, lets see how are body uses them to eventually make all the steroid hormones of our body. By Ryan Patton.
More free lessons at: http://www.khanacademy.org/video?v=-1KeL9wVfOY

- [Voiceover] Now that the lights

at the end of the tunnel a little bit,

I'm going to move a little bit more

quickly through these reactions.

Let me just copy and paste here.

I'm going to clear a
little bit more space.

The body takes squalene

and through a series of ring closing

or cyclization reactions,
it makes cholesterol.

We consume some cholesterol in our diet,

but our body also completes
this reaction in the liver.

Our body takes squalene and turns it into

cholesterol in the liver.

Cholesterol travels through our blood

and it lives in the inside of
cells and on their surfaces.

In the case of integrate organs that use

steroid hormones to communicate,

cholesterol can actually be altered

to form the very characteristic
steroid backbone.

Let me draw that.

These are the four characteristic rings

of the steroid backbone.

As you can see, we are a really long way

off at this point from the very beginning

place that we started which
was that isoprene unit.

Now that I've dragged you all the way

from isoprene to the steroid backbone,

I figured it was only
fair that I showed you

that this actually happens in your body,

and there are actual steroids
floating around your blood.

I mentioned before that there are two

important classes of steroid
hormones in the body,

and those are the sex hormones

and the adrenal cortex steroids.

So with the sex hormones I
mentioned before estrogen's.

We have estradiol and estrone,

and you can see their steroid backbone.

Those are predominately
made in the ovaries,

and their principally involved in

secondary sex characteristics for females.

We have progesterone.

It's kind of the pregnancy hormone.

It's involved in prepping the uterus,

and it's also involved in
maintaining a healthy pregnancy.

Then, we have androgen's.

We have testosterone and androsterone,

and similarly to estrogen's,

those regulate the secondary
sex characteristics,

but more so in males,

and their predominantly
made in the testis.

Moving over to the
adrenal cortex steroids,

we had cortisone,

and cortisol,

and those are the bodies stress hormones.

They have a lot of effects
from anti-inflammatory

to increasing carbohydrate metabolism.

We also have aldosterone.

Aldosterone is one of the main hormones

that regulates our bodies blood pressure

and the fluid volume.

I hope all of these images makes steroids

a little bit more familiar to you

now that you've seen the classic backbone,

and you know how to make it.

Maybe the next time you find yourself

enjoying the soothing relief
of a menthol cough drop

or a savoring delicious
ginger snap cookie,

you'll think about the countless number of

terpenes that you're enjoying.