Understanding the human body is a team effort. That's where the Yachtel group comes in.

Researchers at Yachtolt have been delving into the secrets of probiotics for 90 years.

Yacold also partners with nature portfolio to advance gut microbiome science through the global grants for gut health, an investigator-led research program.

To learn more about Yachtolt, visit yawcult.co.

.jp. That's Y-A-K-U-L-T.C-O.J-P. When it comes to a guide for your gut, count on Yacolt. This is Scientific Americans Science Quickly. I'm Karen Hopkins.

Swimming against a current can be tough, but imagine having to do it in a fluid with the consistency of corn syrup.

That's more or less the challenge faced by mammalian sperm as they race to reach an egg.

That's such a hard race for sperm. It's like a very tough marathon.

Reza Nosrati is a mechanical engineer at Monash University in Melbourne.

He says that sperm are not deterred by tide or averted by viscosity.

In fact, Reza and his team have found that having to navigate the physiological slalom

of the female reproductive tract actually helps sperm swim with optimal efficiency

and may guide them to their desired destination.

The results appear in the journal Cell Reports Physical Science.

When you look at the female reproductive track, I think it's been known for such a long time

that it's a very complicated environment.

As sperm swim upstream, they make their way through secretions that vary in thickness and flow rate.

One of the first hurdles comes at the cervix, the gateway to the uterus.

Right at the port of entry to the cervix, there is a very strong flow because of mucose secretions by the cells within the cervix.

That current helps to flush out any harmful disease-causing bacteria, which are not known to

be strong swimmers.

It's kind of like a barrier and a filter to keep the environment essentially favorable

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