Question

Explain the process of spermatogenesis in humans.

Answer 1

Hint: In humans, spermatogenesis takes place in the testicles when males reach puberty, generally around the age of 14 years. It is the process by which diploid cells are converted into haploid male gametes or sperm cells.

Complete Answer:
The testes are the male reproductive organs. They are composed of several different types of tissues to aid in the production of sperm cells. Production of sperm occurs in the walls of the seminiferous tubules from diploid spermatogonial stem cells which divide mitotically to give one primary spermatocyte and one spermatogonial cell.

Primary spermatocytes then enter into meiotic cell division. The first division gives rise to two secondary spermatocytes, and the second meiotic division results in four haploid spermatids. SO from each primary spermatocyte four spermatids are produced.

The four spermatids then undergo the process of spermiogenesis. This is when the shape goes for a round cell to the familiar elongated sperm structure. Microtubules grow to form a tail at one end, with an axoneme at the anterior end. The axoneme is surrounded by many mitochondria which provide the energy for motion of the sperm. The chromatin is tightly packed and the Golgi body forms a cap shaped acrosome around the nucleus. The acrosome contains enzymes necessary for penetrating the protective layers of the ovum. With the influence of testosterone, sperm maturation completes, getting rid of the excess cytoplasm and other contents. A mature sperm consists of the cell body, which is essentially the nucleus and acrosome, and the tail.

This process of maturation occurs in the Sertoli cells that line the lumen of the seminiferous tubules. These are supporting cells which secrete Androgen Binding Protein and testicular fluid as well as protect the developing sperm.

Note: Spermatogenesis completes in the seminiferous tubules. Sperm then move through the epididymis where they complete their maturation process. Addition of supporting substances from the prostate gland and seminal vesicles completes the production of semen.