spermium

Spermium, commonly referred to as a sperm cell, is the male gamete involved in sexual reproduction in animals. In everyday use the term sperm is preferred, while spermium appears in some historical or scientific contexts. Spermium is produced by spermatogenesis in the testes and matures and is stored in the epididymis until ejaculation.

Structurally, the spermium is highly specialized. The head contains the haploid nucleus and is capped by an acrosome that carries enzymes needed to penetrate the egg. The midpiece houses mitochondria that supply energy for movement, and the tail or flagellum propels the cell through the female reproductive tract toward the egg.

Fertilization begins when a spermium reaches the oocyte. After capacitation, it binds to the zona pellucida, undergoes the acrosome reaction to breach protective layers, and fuses its membranes with the oocyte. The paternal and maternal pronuclei then combine to form a zygote, initiating embryonic development.

Count and quality of spermium are assessed in semen analysis. In humans, a typical healthy sample contains tens of millions of sperm per milliliter, with progressive motility and normal morphology influencing fertility. Variation occurs within and between species, reflecting different reproductive strategies and selection pressures.

Clinical relevance: Abnormal production or function of spermium can contribute to infertility. Diagnosis commonly involves semen analysis and hormonal testing, while assisted reproductive technologies may employ techniques to assist fertilization when natural conception is challenging.