The menstrual cycle and the journey of the egg cell is something that is common knowledge, at least to most women. After all, it is the very thing that women are intimate with on a monthly basis as they go through cycles of fertility and menstruation month after month.
The life and times of their male counterpart, the sperm, however is a bit less known. This is probably because sperm can be a bit boring. After all, each month there is usually just one egg cell released in a woman’s body. Sperm, on the other hand, is mass-produced and therefore not as rare or special.
However, if you take a closer look, sperm can be much more interesting than it lets on. To help you appreciate this, here are a few amazing facts about sperm’s journey from the testes all the way to the egg cell!
15 Sperm Production
Those lovable little microscopic tadpole-like cells called sperm are produced in the seminiferous tubules of the male testes. Each tubule contains stem cells that continually multiply to produce sperm. It takes about five different stages before the stem cells can produce sperm as we all know and love it. From start to end, it takes about two months to complete sperm production, but the male body is continually working on each step of the process to ensure that supplies don’t run out. Talk about efficient!
14 Secrets of Semen
In order to survive the long journey through the woman’s reproductive tract, the sperm needs provisions. With each ejaculation, about a teaspoon of semen is thrown out. Semen is especially produced lovingly by the prostate for two specific purposes.
First, it is meant to provide nutrition for the sperm cell’s long quest towards the egg. In fact, scientists have actually studied the nutritional content of semen. It contains proteins, sugars and a bunch of vitamins and minerals to help nourish the sperm. It kind-of makes you wonder why they didn’t just go ahead and publish the percent of nutritional value per serving of it!
Second, semen is an excellent medium in which the sperm can move more effectively. As we will talk about later, the vagina is a hostile place for sperm and semen makes it easier for sperm to just go ahead and do its job.
Over the course of his lifetime, a man will continuously produce billions upon billions of sperm cells. On average, however, a man will have about 20 million sperm cells per millilitre of semen. That’s a total of about 40 to 50 million per ejaculate!
If you’re wondering just how small a sperm is, think about it this way: that single teaspoon of ejaculate we were talking about earlier is only 1% sperm by volume. Mind-blowing how small they are, isn’t it?
12 Keep it Coming
Sperm doesn’t exactly have a long shelf life, which we’ll discuss a bit later. The longer they hang around in the testes, the more prone they are to damage. To maintain healthy sperm that’s just right for making all those babies, it is therefore better for a man to ejaculate frequently to just replenish the supply.
This could be one reason why men are just so biologically driven to having more sex!
Take one good look at the image and you’ll have a pretty good idea of what a healthy sperm looks like: with oval heads and single long tails. This is opposed to abnormal sperm, some of which may have different head shapes, two heads or two tails, or even just a tiny miniature head that’s barely there. Healthy sperm are typically better equipped to make the long journey towards the egg cell. They are usually the ones with the effective wriggle that can propel it forward through the depths of the vagina.
10 Many Aren’t Normal
Don’t think that just because you’re all normal and fertile, it automatically means that all your sperm are perfect. Even in a fertile sample of semen, up to 50% of sperm could be abnormal!
However, since these sperm may not be able to function as well as healthy sperm, they’re less likely to reach the egg cell in time for an effective fertilization. Although it is still possible for an unhealthy sperm to fertilize the egg.
9 Those Whips
Those little tails or whips at the end of each sperm cell are called flagellum. This is composed of microtubules with proteins attached to it. It moves in a twisty, rotating manner, literally causing the sperm to swim around to where it needs to go.
Incidentally, flagella can also be found in certain bacterial and protozoan species, where they also function in the same way: to get around!
8 Hostile Environments
For the unsuspecting sperm cell, the uterus is one of the most hostile of environments. This is especially when the lady in the equation is not fertile. During this time, her cervical mucus will be thick or creamy, which to sperm would be like swimming through mud. This is pretty much the vagina’s way of telling those poor little things that they shalt not pass.
If, however, the cervical mucus is thinner, with an almost egg white-like consistency, then it is much more survivable for our spermy heroes. However, that doesn’t mean that it’s hospitable.
7 Life Spans
Once in the female reproductive tract, sperm can survive for an average of two days. However, some of the hardiest are known to survive for up to five. Because sperm don’t have that long to live, it’s a mad rush for every single one to get up and fertilize the egg cell. If the female is infertile, then death is inevitable for these hardy heroes.
Oh, and for all those sperm cells that don’t end up in the female reproductive tract? They only survive for about an hour, at most.
6 Survival of the Fittest
The journey is long and treacherous and only the best sperm will survive. After all, the egg cell and likely the female carrying it is very picky. It only wants the fastest and healthiest of sperm to fertilize it. This is probably why the female reproductive tract is so designed to weed out all the weaklings and have all the strongest sperm in the end. (Although, of course, there are flukes, occasionally.)
If a man wants to improve the health of his sperm, however, he needs to stay in shape and lead a healthy lifestyle himself.
5 Timing is Everything
If you’re trying to get pregnant, timing is everything. Given that sperm only have a limited life span inside the female reproductive system and that the egg cell is only fertile for a specific amount of time as well, all the stars will have to align before a baby is made.
The importance of timing is probably why calendar methods of contraception are fairly accurate when done correctly.
4 Wrong Direction
When the sperm meets the egg cell, it’s likely to happen within the fallopian tubes. There’s just one problem: there are two of them! So when the sperm reaches the uterus, they have to make a tough choice: swim left or right? More accurately, though they just go through whichever way is easier.
The sperm therefore have a fifty-fifty chance of getting a once-in-a-lifetime chance to meet up with the egg. If he swims in the right direction, he’s in luck! Although that still isn’t a guarantee he’s going to win it all. However, if he swims in the wrong direction, nothing can help him, really. That is, unless two eggs were produced at once!
3 First Doesn’t Win
In the game of life, just because you’re the strongest and the fastest doesn’t necessarily mean you’re going to finish first. In the game of sperm, there’s another layer to that rule: just because you finish first doesn’t mean you’re going to win the race!
As the head of each sperm hits the egg, the tip of the head burrows into the thick jelly-like coating of the egg and has to get through that before it reaches the egg cell. Because it has to go through this extra layer of defense, just because a sperm gets there first doesn’t mean that he’s going to be the one to fertilize the egg! In some cases, a sperm that is late to the party has the advantage, as the egg’s layer is already weakened somewhat by other sperm.
2 Instant Change
Once the winning sperm finally meets the egg, something magical happens. The surface of the egg cell instantly changes, making it thick and even more inhospitable, blocking any other sperm from entry. In the race for the egg cell, after all, there can only be one. Most of the sperm also disintegrates, as the pair bond to form a union that is now inseparable.
As for all the other unfortunate sperm? Well, this is the end of the line for them.
1 Mixing and Matching
Inside the egg cell, or what is the fusion between the sperm and egg cell, the 23 chromosomes from the egg cell and the 23 from the sperm cell meet up. These 46 chromosomes make up the formula for what is a unique human being. Soon after the chromosomes merge, the fertilized cell begins the process of mitosis. That is, it begins to divide into two perfect daughter cells with exactly the same mix of genes from both mom and dad!
Given all that has to happen to produce a baby, it’s something of a miracle it happens so often!