Dr. Yara Haridi

Yeah, yeah, yeah.

No, not the grizzlies.

Bone density, absolutely.

So definitely our hormones affect how most of our skeleton grows, but particularly our bones.

This is why women are very susceptible in menopause to losing bone density.

We start to lose some of our estrogen and estrogen.

that helps us maintain bone density.

It basically tells our bone cells, these things called osteocytes, to be more sensitive in certain ways so that they can help other cells communicate.

So a little bit of bone bio 101.

But basically within our bones, there's really just the three cell types.

There's the osteoclasts, the bone destroyers, osteoblasts, the bone builders, and then osteocytes, the ones that live and maintain inside the bones.

But when we lose hormones or certain types of hormones, it messes with the way that they communicate.

And so all of a sudden you have more osteoclast activity.

So removing too much bone and not enough building of bone.

What happens when that?

We get osteoporosis.

Yeah.

And so totally, hormones play a huge role in how we maintain our skeleton, particularly bone density.

This is also a problem when it comes to space travel because we lose bone density if we're not actually working out or getting gravity acting upon our skeleton.

So that's how the twin experiment where they sent one, yeah, one astronaut in space and left his twin on Earth, came back, and I think he had lost some crazy amount of bone density.