Sperm aren't the graceful swimmers you think they are, according to new research. Instead of gracefully waving their flagella and swimming through the vaginal tract, most sperm actually bump along the walls and crash into each other on the way.
The research, published in the Proceedings of the National Academy of Sciences, explains that sperm don't really "swim" per say - instead they cling to the sides of the reproductive tract and bump their way along. Imagine a crowded ice skating rink for novices. Most people cling to the wall, slipping and sliding and half-dragging themselves along. That's essentially what sperm are doing inside the female reproductive tract.
In fact, sperm almost never swim, the researchers say. The only time they leave the walls is when the tract makes a sharp corner. At that point, the sperm wind up swimming along until they crash into the other wall, and continue their unsteady journey onwards.
If this sounds ridiculous looking, you're right, says Dr. Denissenko at the University of Warwick who did the study. ""I couldn't resist a laugh the first time I saw sperm cells persistently swerving on tight turns and crashing head-on into the opposite wall of a micro-channel," she said.
Figuring out how sperm swim is important for couples who have to turn to fertility treatments for help conceiving. ""In basic terms – how do we find the 'Usain Bolt' among the millions of sperm in an ejaculate," explained Dr. Kir,man Brown, at the University of Warwick. "Through research like this we are learning how the good sperm navigate by sending them through mini-mazes." If you can figure out which characteristics make the most successful sperm, you can pick the strongest ones to use during fertility treatments.
Bonus: there's a movie to go along with the paper.
Photo: Wikimedia Commons