Human cells come in different sizes.
Some cells are really small, some are relatively large.
The largest cell in the human body is the egg cell, while the smallest cell in the body is the sperm cell.
How large is the female egg cell?
To put things in perspective, egg cells are about 20 times larger than sperm cells. They are spherical in shape and measure about 0.1 millimeters in diameter.
One amazing thing about them is that unlike other cells of the body, they can actually be seen with the naked eye! Some estimates suggest that these cells are about the size of a grain of sand.
Each egg cell has a central nucleus that contains the female’s genetic material. The central nucleus is surrounded by a yolk (cell plasma), which contains the nutritional elements that are necessary for the development of the egg cell.
The medical name of egg cells is 'ova' (a single egg cell is called an 'ovum').
The ova or eggs are produced in the ovaries and are present at birth as “immature eggs”. When puberty is reached, the female's body would release one mature egg every month during ovulation for possible fertilization.
How small are sperm cells?
Sperm cells are really small in volume.
The head of a sperm cell measures just about 4 micrometers in length. That is just a little bit smaller than a red blood cell.
Sperm cells are very unique, they are divided into three parts:
- The head (Contains genetic material)
- The body (Made up of many energy-producing structures called mitochondria)
- The tail (Very important for their swimming abilities)
Sperm cells are actually produced in very large quantities.
The average man produces about 1500 sperm cells every second, in fact, a man would produce about 500 billion in his lifetime. It also takes about two and half months for sperm cells to grow and mature in the testes.
Sperm cells are known to survive just a few minutes outside a man's body but can live for up to 5 days inside the body of a woman.
If properly stored and frozen, sperm cells can live for several years.