Question

Graafian follicles are found in
(a) Testis of mammal
(b) Ovary of frog
(c) Ovary of cockroach
(d) Ovary of mammals

Answer 1

Hint: Inside the female, the reproductive organ which produces ovum there is a large sac- like structure of spheroid cellular aggregation called Graafian follicle where each follicle contains a maturing ovum which is controlled by a follicle- stimulating hormone.

Complete step by step answer:
The Graafian follicle is the stage soon after the first meiotic division has completed but before ovulation. The Graafian follicle produces two major roles in maturation which is release of a fertilized oocyte and information of corpus luteum which is important in implantation and maintenance of the embryo. The Graafian follicle is quite large in size because of the increase in the size of the follicular antrum. In humans, only one of these follicles will actually be ovulated during each menstrual cycle.

So, the correct answer is ‘(d) Ovary of mammals.’/b>

Additional Information: Following changes occurs in Graafian follicle at ovulation:
- The oocyte and the corona radiata separates from the cumulus oophorus.
- The primary oocyte completes meiosis I and results in formation of a secondary oocyte. It then undergoes its second maturation division, which only proceeds to metaphase II. It will only complete cell division if fertilization occurs.
- In mature Graafian fluid the amount increases and the ovum is pushed to one side surrounded by cumulus oophorus.
- The external follicular is surrounded by theca and theca externa, with the increase of intrafollicular pressure follicle ruptures.

Note:
- Two hormones luteinizing hormone and follicle- stimulating hormone produced by the pituitary gland causes the development of the primordial follicles and further to form mature follicles.
- Stages of maturation of ovum includes:
Primordial follicle
Primary follicle
Secondary follicle
Antral follicle
Mature follicle-Graffian follicle