Seminiferous Tubule – Class 12 | Chapter – 3 | Biology Short Notes Series PDF

Seminiferous Tubule: A coiled structure with a diameter of 150 m and a length of 80 cm is known as a seminiferous tubule. Seminiferous Tubules are located in the testicles, the two oval-shaped organs on either side of a male’s penis. There are around 800 seminiferous tubules in each testicle, and this is where meiosis and subsequent development of spermatozoa occurs.

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In a mature adult male, each of these tubules creates thousands of sperm every second. The tubules are tightly looped throughout the testes, and are incredibly long: perhaps as much as a mile between the two testes! Their tissue is lined with Sertoli Cells, a specialized cell type that is responsible for creating new sperm. They do so by secreting a protein that increases the concentration of testosterone inside the seminiferous tubules.

Structure of Seminiferous Tubules

Structure of Seminiferous Tubules

  • Seminiferous tubules are located in the testicular lobules. Their structure is highly coiled in nature. It is the site for spermatogenesis within the testes.
  • They are lined with germinal epithelium.
  • The inner side has a lining of two types of cells – Spermatogonia and Sertoli cells.
  • Spermatogonia are the male germ cells that undergo meiotic divisions, giving rise to primary spermatocytes. The primary spermatocytes undergo subsequent meiotic divisions producing secondary spermatocytes which is then followed by spermatids. These spermatids eventually mature and undergo metamorphosis giving rise to spermatozoa, the male gametes.
  • Sertoli cells act as nurse cells and nourish the germ cells in the testicular lining.
  • Adjacent to the seminiferous tubules, there are large polygonal cells called Leydig cells or interstitial cells that secrete the male hormone testosterone.

Types of Seminiferous Tubules

  • Convoluted Tubules: These are located on the sides of the testes, where sperm cells are produced
  • Straight Tubules: These are short canals that transport sperm cells to the rete testis, a network of small tubes in the testicle that helps move the sperm cells from the testicle to the epididymis

Role of Seminiferous Tubules

  • They play a role in the production of sperms.
  • They help in the maintenance of sperms.
  • They also play a role in storage of the sperms.
  • They create androgens and release them.
  • During the process of meiosis, the Sertoli cells that line the seminiferous tubules undergo the process of differentiation to be converted into sperm.

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By Team Learning Mantras