Egg fertilization is often described as an epic swimming meat: millions of sperm floats because they can do one to the eggs – the fastest, strongest, healthy sperm of all of them conquer and fall into the eggs. Jean For future children.
But how does this happen really? Do sperm really run for eggs?
Yes and no, David j millerA professor in the Department of Animal Sciences at Urbana-Shampain of Illinois University told Live Science. “In this, the important player is actually a female reproductive path.”
Sperm floats during this process, but “the major movement is actually provided by contraction of the female path,” Miller explained. “There are contractions of the uterus, for example, which are like contractions of the GI tract that can move fluid through the uterus.”
A 1996 study Miller noted how efficient these contractions are, Miller noted. Scientists deposited sperm-shaped beads in the uterus of 64 women, and some beads travel all the way for fallopian tubes-where fertilization is usually done-within-within.
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It is understandable that sperm will require some additional help, because when sperm floats in one direction, the eggs need to travel in the opposite direction to meet them, Sabine KoleA full professor of Anatomy and Developmental Biology at University College Dublin School of Medicine and Medical Sciences told Live Science. The egg cannot swim, so short hair called cilia instead helps it with it.
“Cilia defeated Oocyte,” or egg, Kole said. “Because sperm are coming from the opposite direction, they have to struggle against the stream created by cilia.
In fact, the movement of an individual sperm is less than an attempt to move forward and tries to move forward internalOn the middle of the path, Kole said. If sperm reach very close to the sides, they stick and lose their front speed.
However, just because a sperm is going to come first, it does not mean that it is found to fertilize. “Sperm require some final maturity that occurs in the female path, and it is up to time,” Miller said. “So sperm who win the race,” so to speak, more time is needed before they can actually fertilize the eggs. “
Miller said, “When they meet that maturity, they cannot be there.” “They can be replaced by some other gradual sperm carrying, which was the time to meet that maturity.”
But even those low-peripcu sperm are more successful than the vast majority of sperm that accumulate. Since the female breeding path pushes the sperm together, it also cuts inauspicious individuals from the swimming team.
Miller said, “Less than 1% – perhaps up to 2 or 3% of sperm that have actually accumulated – make it all where the egg is,” Miller said. “Many of them are swept away from the path. Some are eaten by immune cells in the uterus, as sperm are exotic.”
70% of sperm also do not make it in the past of the cervix, Kole said. “Sperm are trapped there and cannot free themselves,” he said.
For some sperm that make it in the fallopian tube, the goal is to keep as much as possible and then stick to the wall as they wait for the egg to arrive. This is another place where female breeding organs are choosing the winners: scientists have noticed that there is more likely to tie the normal looking sperm to the wall, Miller said, and the wall bound provides some metabolic benefits that increase their lifetime.
Then, once the egg arrives, the fallopian tube-also known as the ovarum-allows the sperm that looks healthy to the wall. “As soon as a sperm is not well, Dimbavahini does not release it,” Kole said. “It is the main selector of good sperm.”
This is not an ideal system, of course. “Obviously, we have genetic diseases that come through sperm. So it is not always true that the best genetic is the best,” Miller said.
At each step, the female reproductive tract is performing its best to remove the lower-fit sperm so that only healthy sperm reach the eggs. In this way, fertilization is less like a race and more like a job interview.
“There are some qualifications that you should be able to apply for a job,” Miller said. “But also, sperm that have qualifications will be when the job is open – the time when the egg is ovulated.” But in the end, it is the female breeding path that chooses the best candidate.
