What is a Sperm Cycle? How Are Sperm Made?
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What are sperm? How do they become sperm?
The cycle of human sperm, known as spermatogenesis, is a complex process that occurs within the seminiferous tubules of the testicle. Each testicle has hundreds of seminiferous tubules, which are coiled structures packed within the testicle. A sperm cycle takes somewhere between 62 and 74 days. Producing a mature sperm involves several stages, beginning with spermatogonia:
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Spermatogonial Phase: Spermatogonia are germ cells located in the outermost layer of the seminiferous tubules. These cells undergo mitosis, which produces more spermatogonia with the same number of chromosomes as the original cell.
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Spermatocyte Phase: Some spermatogonia differentiate into primary spermatocytes. Each primary spermatocyte undergoes meiosis, a specialized form of cell division that reduces the chromosome number by half. This process results in two secondary spermatocytes, each with half the chromosome number of the original spermatocyte.
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Spermatid Phase: The secondary spermatocytes undergo a second meiotic division to form four spermatids. These cells are haploid, meaning they have half the number of chromosomes compared to the original spermatogonia.
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Spermiogenesis: Spermatids then undergo a series of morphological changes to become mature spermatozoa. During this phase, spermatids develop a head, midpiece, and tail, transforming from round cells into the streamlined sperm shape that you're familiar with. This process involves the development of the acrosome (a cap-like structure that helps in fertilization), and the elongation of the tail for mobility.
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Spermiation: The final stage involves the release of mature spermatozoa from the Sertoli cells into the lumen (inner area) of the seminiferous tubules. From there, spermatozoa are transported through the epididymis, where they undergo further maturation and gain motility.
Sperm are stored in the epididymis for 2-3 weeks. During ejaculation, sperm are transported into the vas deferens (the tube that is "snipped" during a vasectomy) and eventually are combined with seminal fluid.
*This post is for educational purposes only, and should not be taken as medical advice. If you have personal medical questions, consult with your personal physician*