What is Spermatogenesis?

Spermatogenesis is the process by which the male body makes sperm cells.

It happens in the testes, inside tiny coiled tubes called seminiferous tubules.

It starts during puberty and continues for a man’s entire life.

The goal is to make sperm that can fertilise a female egg.

Where Does It Happen?

• In the testes of males

• Inside tiny tubes called seminiferous tubules

• The process is controlled by hormones and begins at puberty

The Full Process of How Sperm Is Made (Spermatogenesis)

Step 1: Spermatogonia (Starter Cells)

• These are stem cells at the edge of the seminiferous tubules.

• They have 46 chromosomes (diploid).

• Some stay as stem cells to keep the process going.

• Others divide by mitosis to make primary spermatocytes.

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Step 2: Primary Spermatocyte

• Each one is diploid (46 chromosomes).

• It prepares for meiosis, which is a special type of cell division to reduce chromosome number.

• It goes through meiosis I, where the chromosomes are mixed and split.

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Step 3: Secondary Spermatocytes

• After meiosis I, the primary spermatocyte becomes two secondary spermatocytes.

• These cells now have 23 chromosomes (haploid).

• They are halfway to becoming sperm.

• They go through meiosis II, a second division.

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Step 4: Spermatids

• Each secondary spermatocyte forms two spermatids (total of 4 from one primary spermatocyte).

• Spermatids are round, immature, and can’t swim yet.

• They still have 23 chromosomes.

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Step 5: Spermiogenesis – Maturing into Sperm

• Spermatids now change shape:

• They grow a tail (flagellum) for swimming

• The nucleus becomes smaller and more compact (to carry DNA)

• They lose extra parts they don’t need

• This transformation makes them into spermatozoa (mature sperm).

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Final Product: Spermatozoa (Sperm Cells)

• These are long, streamlined cells with:

• A head (with DNA and enzymes to enter the egg)

• A midpiece (with mitochondria for energy)

• A tail (to swim toward the egg)

• Each sperm has 23 chromosomes — half of the father’s genetic information.

Favourite part/ note/ summary— Spermatogenesis is the process where sperm is made. There are 5 stages Spermatogonia, Primary Spermatocyte, Secondary Spermatocytes, Spermatids.

Spermatogonia is the starter cell, starts in testes inside tiny tubes called seminiferous tubules. Spermatogonia (starter cells) divide to form primary spermatocytes. Primary spermatocytes split into secondary spermatocytes (meiosis I).

Secondary spermatocytes split again into spermatids (meiosis II). Spermatids grow tails and change shape to become sperm (spermatozoa). Each sperm has 23 chromosomes and can fertilize an egg.