Sperm cells are the male reproductive cells.
They were first discovered by a Dutch scientist, Antonie van Leeuwenhoek in 1677 when he looked at his own semen under a microscope.
He was also the first person to observe bacteria, muscle fiber patterns and the flow of blood cells in capillaries. His findings also earned him the name 'father of microbiology'.
The word 'sperm' was coined from the Greek word 'sperma', which means 'seed'.
When a sperm cell fuses with a female egg, they form a single-cell called the zygote, which can then grow to become a baby. (It's interesting to know that every one of us spent about 24 hours as a single cell)
Sperm cells are very unique. In this post, we would be looking at 11 things that make them very special.
1. They are produced at very fast rates.
Unlike women that are born with all their egg cells, men produce new sperm cells every day. The average man produces about 290 million new sperm cells per day, that is about 1,500 sperm cells every second! A man would also produce about 500 billion sperm cells in a lifetime.
2. They are released in large quantities.
Sperm cells are not only made at high rates, they are also released in large quantities. When a man ejaculates, he releases about 2-5 milliliters of semen, with each milliliter containing at least 20 million sperm cells. What this means is that in a single ejaculate, there could be 20-100 million sperm cells. Those are 'wowing' numbers!
3. They take their time to get matured.
Considering how many sperm cells are produced and released, you might think their maturation time would be really short. However, that is not the case.
Despite their high rates of production, it takes about 2-3 months for each sperm cell to mature. When they are first made, they are immobile and infertile. They have to go through different stages of differentiation before they are ready for ejaculation.
4. Sperm cells have a unique structure.
Each sperm cell is made up of three parts: the head, the middle piece, and the tail.
The head contains the nucleus which carries genetic material. It is conical in shape and has a tip called the acrosome. The acrosome contains hydrolytic enzymes which help to penetrate the female egg cell during fertilization.
The middle piece lies in between the head and the tail and contains lots of mitochondria (power-producing structures) that provide the energy needed for its swim.
The tail is the longest part of the cell. It is a 'whip-like' structure that propels the cell forward during its swim.
5. Most of those released are deformed.
Don't be surprised about this, but about 90% of sperm cells are deformed. They are either released without tails, have coiled tails, two tails, two heads or a deformed head.
According to the World Health Organization, a man can be considered to have a normal sperm count if more than 5% of his sperm cells are well formed.
6. They prefer low temperatures.
Have you ever wondered why guys have their testes hanging in a scrotal sac? Well, it has to do with the temperature.
Sperm production requires a cooler temperature (about 2 degrees Celsius less than the body's core temperature). An increase in temperature can affect sperm production and lead to infertility. This is one reason why guys are advised not to use their laptops on their laps.
7. They are the smallest cells.
Guess what the largest cell is? The female egg cell.
A sperm cell is in fact 20 times smaller than an egg cell.
8. They prefer a different sugar as their energy source.
While most cells in the body thrive on glucose as their source of energy, sperm cells use fructose. Fructose is one of the important nutrients contained in semen, it helps to nourish sperm cells and provides energy for their swim.
It is sometimes measured in the analysis of semen during fertility testing.
9. They can survive for a few days in a woman's body.
Sperm cells can survive for only a few minutes outside a man's body (like on a bedsheet or clothing). However, they have been found to live up to 5 days in a woman's body.
In laboratories, sperm cells can be frozen and stored for several years.
10. They respond to a man's lifestyle.
Sperm quality can be affected by a person's lifestyle. Activities like cigarette smoking and excessive alcohol intake can cause a decreased fertility in men. Obesity also makes a man more likely to have a low sperm count.
11. They have their own bank.
Sperm cells are one of the few cells in the body (like blood cells) to have their own bank. Sperm banks are places where sperm cells are donated, stored and supplied to people desirous of children.
Sperm cells can be stored in these banks for several years without losing their viability. The largest sperm bank in the world is Cryos International, a Danish company. It holds about 170 liters of sperm and supplies more than 80 countries.