Arrange the following stages of the ovarian follicle in the order in which they develop:
A. Follicle with a fluid-filled cavity called antrum
B. Primary oocyte surrounded by a layer of granulosa cells
C. Follicle that ruptures to release the secondary oocyte
D. Follicle surrounded by more layers of granulosa cells and a new theca
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → B, D, A, C
Each follicle stage in the ovary can be known by its features. The order follows the growth of the follicle from the primary follicle to the Graafian follicle.
(B) Primary oocyte surrounded by a layer of granulosa cells is the primary follicle, the first stage.
(D) Follicle surrounded by more layers of granulosa cells and a new theca is the secondary follicle, which comes next.
(A) Follicle with a fluid-filled cavity called antrum is the tertiary follicle. At this stage the primary oocyte completes its first meiotic division.
(C) Follicle that ruptures to release the secondary oocyte is the mature Graafian follicle, the last stage; its rupture is ovulation.
So the correct order is B, D, A, C.
NCERT Extract:
Gametogenesis – “… Each primary oocyte then gets surrounded by a layer of granulosa cells and is called the primary follicle (Figure 2.7).”
Gametogenesis – “… The primary follicles get surrounded by more layers of granulosa cells and a new theca and are called secondary follicles. The secondary follicle soon transforms into a tertiary follicle which is characterised by a fluid filled cavity called antrum.”
Gametogenesis – “… The tertiary follicle further changes into the mature follicle or Graafian follicle (Figure 2.7). The secondary oocyte forms a new membrane called zona pellucida surrounding it. The Graafian follicle now ruptures to release the secondary oocyte (ovum) from the ovary by the process called ovulation.”
