Swimming sperm

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Sperm gets ejected from the penis, enters the vagina, and swims up the reproductive tract until they reach the egg to fertilize it. Barely years ago, it was considered a major scientific breakthrough when scientists came up with the idea that a fully formed, tiny human inhabited the head of each sperm — totally debunked and untrue. Fortunately, as the human body has evolved over thousands of years to maximize fertility potential, so has our scientific understanding about sperm.

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However, those species also tended to have high rates of abnormal or damaged sperm. The second part of the study, identifying the association between sperm shape and sperm damage, was published today in Journal of Evolutionary Biology. The first part, which describes that screw-shaped sperm swim faster, was published in Evolution in July

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Despite the huge global demand for both fertility treatment and contraception, there are surprisingly few options to boost male fertility, or for male contraception. To have more options, we really need a better understanding of how human sperm work. Unfortunately, they are incredibly difficult to study in the lab.

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For full functionality, it is necessary to enable JavaScript. Here are instructions how to enable JavaScript in your web browser. Healthline Media, Inc.

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With every ejaculation, men produce around million sperm cells. How much do you know about these wiggly little cells? Read on for 7 surprising facts about sperm.

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Sperm competition is now recognised as a potent selective force shaping many male reproductive traits. While the influence of sperm competition on sperm number is widely accepted, its effects upon sperm size remain controversial. It had been traditionally assumed that there is a trade-off between sperm number and sperm size, so that an increase in sperm number would result in a decrease in sperm size, under conditions of sperm competition. Contrary to this prediction, we proposed some time ago that sperm competition favours an increase in sperm size, because longer sperm swim faster and are more likely to win the race to fertilize ova.

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By Clare Wilson. We thought we had sperm figured out, but it turns out they wiggle in mysterious ways. The finding could shed light on why some men have fertility problems, and lead to more accurate diagnostic tests for infertility.

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The predictable swimming sperm featured in health class videos are rather uncharacteristic portraits of the life of these sex cells. Spermatozoa actually spend most of their time resting up in the male reproductive tract so they can make a dash to the egg once the opportunity arises. It has long been known that the little swimmers get their cue to start moving from a big change in pH levels, but a new study explains just how that shift occurs: a specific molecule in the sperm cells' tails releases protons when the time is right. So releasing many of those protons from inside of the sperm cells lowers the internal acidity, a cue to the sperm cells to start flipping their flagella.

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