list the varios steps that lead to the formation of egg of hen


  • The ovum is formed by the process of oogenesis.

  • It starts during embryonic growth and millions of gamete mother cells (oogonia) are formed in the foetal ovary.

  • These cells undergo meiosis, but get temporarily arrested at the prophase and are called primary oocytes.

  • Before reaching puberty, a large number of primary oocytes degenerate and the remaining ones get surrounded by layers of granulosa cells and new theca and are called secondary follicles.

  • The secondary follicles are then converted into tertiary follicles that have characteristic fluid-filled cavity called antrum. At this stage, the primary oocyte present within the tertiary follicle completes meiosis, which results in the formation of haploid secondary oocyte and a tiny polar body.

  • This tertiary follicle further changes into the Graafian follicle. The secondary oocyte is surrounded by the zone pellucida.

  • Then the Graafian follicle ruptures to release the ovum by ovulation.

  • 1
What are you looking for?