Question

Polar bodies formed during the formation of oocytes are

• A. Smaller cells formed due to unequal meiosis.
• B. Structures which bud off during oogenesis.
• C. Structures formed during spermatogenesis.
• D. Daughter cells formed after mitosis.

Answer 1

The correct option is A Smaller cells formed due to unequal meiosis.

During oogenesis in human females, the primary follicles get surrounded by layers of granulosa cells and a new theca and called secondary follicles. The secondary follicle transforms into a tertiary follicle which is characterised by a fluid filled cavity called antrum. The theca layer is organised into an inner theca interna and an outer theca externa. It is important that it is at this stage that the primary oocyte within the tertiary follicle grows in size and completes its first meiotic division. It is an unequal division resulting in the formation of a large haploid secondary oocyte and a tiny first polar body. The secondary oocyte retains bulk of the nutrient rich cytoplasm of the primary oocyte. The secondary oocyte undergoes second meiotic division just before the fertilisation. The second meiotic division is also unequal and results in the formation of a second polar body and a haploid ovum (ootid). Both the polar bodies are produced as a result of unequal division and do not participate in development of embryo.