Human Biology

1.67. Human Sperm http://www.ck12.org

1.67 Human Sperm

• Explain what sperm are and how they are produced.

How many sperm does it take to fertilize an egg?

It might only take one sperm to fertilize an egg, but that sperm is not alone. Hundreds of millions of sperm can be
released during sexual intercourse.

Sperm and Sperm Production

Sperm(Figure1.129), the male reproductive cells, are tiny. In fact, they are the smallest cells in the human body.
What do you think a sperm cell looks like? Some people think that it looks like a tadpole. Do you agree?

Sperm

A sperm has three main parts:

1. The head of the sperm contains the nucleus. Thenucleusholds the DNA of the cell. The head also contains
   enzymes that help the sperm break through the cell membrane of an egg.


2. The midpiece of the sperm is packed with mitochondria.Mitochondriaare organelles in cells that produce
   energy. Sperm use the energy in the midpiece to move.


3. The tail of the sperm moves like a propeller, around and around. This pushes the sperm forward. A sperm can
   travel about 30 inches per hour. This may not sound very fast, but don’t forget how small a sperm is. For its
   size, a sperm moves about as fast as you do when you walk briskly.