Sperm develop in the testicles and mature until they are ready to fertilise an egg. The sperm cells have a long tail and head that contains genetic material.
It takes 74 days for the average sperm to fully mature. Despite this, people with normal sperm counts do not need to worry about running out of sperm.
The sperm cell
Unlike cells in other tissues, sperm don’t stop making new ones after puberty. As long as testosterone is present, these simple round cells continue to transform into sperm, which are released into the semen during nocturnal emissions. These sperm, also known as spermatozoa, are the little swimming critters that get women pregnant.
As they make their way through the testicles, sperm are subject to a battery of chemical changes. These chemical changes help sperm orient themselves towards the egg (ovum) that they will fertilize. They also trigger a release of hormones like oxytocin and dopamine, which promote feelings of bonding and sexual arousal.
Once a sperm has reached the egg, it must be able to pass on its genetic material in order to reproduce. Its cell structure is highly adapted to this purpose. It contains 23 chromosomes, half the number of chromosomes found in a normal cell. Its head, or acrosome, is shaped like an egg and contains inactive enzymes. When it comes into contact with diffusible molecules on the surface of an egg, these enzymes are converted into active forms that can break through the egg’s membrane and fertilize the ovum.
The middle section, or body of a sperm, takes up around 10% of its total length. This part does not contain the sperm’s genetic material, but it does have tightly concentrated mitochondria, which provide energy for sperm movement and swim to their destination. The tail section is an elongated, thin structure that makes up 80% of the sperm’s overall length. Its function is to propel the sperm forward, and it has an unusual shape that looks something like a propeller.
The sperm tail
The sperm tail, also called the flagellum or spermatid, is a long, whip-like structure that provides the movement of the gamete. This movement is necessary for the sperm to travel up the female reproductive tract and reach the egg for fertilization.
The tail is connected to the head and middle portion of the sperm cell by a slender, hairlike bundle of filaments known as the axoneme. This axoneme is made of microtubules and other proteins that help the sperm tail whip and undulate to propel the sperm towards the egg.
A team led by David Clapham at Harvard Medical School, has identified a protein in the sperm tail that controls this movement. They found that mice lacking this protein have sluggish sperm cells that can’t propel themselves to the egg. They found that the protein, which is named CatSper, is a calcium channel.
Although ejaculation is a natural bodily function, frequent masturbation can cause fatigue or discomfort in the genital area. It can also lead to a decrease in sperm count over time. However, it is important to note that your body releases millions of sperm every day. So, you should not worry about wasting sperm. In addition, if you are trying to conceive, limiting your daily ejaculation can increase your chances of success. However, it is up to you to decide whether or not to limit ejaculation.
The sperm head
If the head of a sperm is not properly formed, it can affect its ability to fertilize a woman’s egg. An abnormally shaped sperm may also have too few or too many chromosomes, which can lead to birth defects in the baby. This type of sperm morphology is called macrocephaly. A homozygous mutation in the aurora kinase C gene can cause this condition.
The head of most animal sperm is closely apposed to the nuclear envelope and contains a specialized secretory vesicle called the acrosome. When the acrosome is released into an egg during spermiation, it exposes and releases hydrolytic enzymes that help the sperm penetrate the egg’s outer coat. The head of the sperm is also a rich source of mitochondria, which provide energy for the flagellum.
In addition, the head of a normal sperm is oval-shaped and possesses an intact midpiece, which makes it easier for the sperm to swim in a straight line. The sperm head also has a single, uncoiled tail. Sperm that are defective in any of these areas can’t fertilize an egg and will not cause a pregnancy. Abnormal sperm morphology can sometimes be caused by lifestyle changes, like diet and exercise, and can be corrected with treatments like testosterone replacement therapy. A doctor can advise you on the best course of action.
The sperm nucleus
The sperm nucleus, also called the acrosome, contains enzymes that help break down the barriers of the female reproductive system to allow sperm to enter. It is also where genetic information resides and where sperm gets its energy for movement. The sperm nucleus is a very small structure, four to five micrometres in length and two to three micrometres wide. It is located in the head of the sperm.
In mammals, sperm cells are produced in the testis. Special cells in the testes go through meiosis to produce identical copies of themselves, known as spermatids. These cells have 23 chromosomes, one of each X and Y.
Sperm cells are streamlined in design to meet the challenges of a long journey through the female reproductive tract, where they compete with hundreds of millions of other sperm. They have a tail to help them move, mitochondria for energy and genetic material to transfer, and proteins that enable them to penetrate the egg cell.
The sperm tail, also called the flagellum, makes up about 80 percent of the sperm’s length. The tail moves in a wave-like fashion to propel the sperm for swimming, and the principal piece and the end piece of the flagellum help generate this motion. Mitochondria produce the energy needed for this motion from sugar, and the sperm cells get the rest of their energy from seminal fluid.