Question

Which part of the ovary in mammals acts as an endocrine gland after ovulation?
(a) Stroma
(b) Germinal epithelium
(c) Vitelline membrane
(d) Graafian follicle

Answer 1

Hint: A structure present in the mammalian ovary within which an ovum develops before ovulation (release of eggs from woman ovaries) . The structure also has a fluid- filled antral cavity which is known as antrum.

Complete answer:
After ovulation, the Graffian follicle is transformed into a yellow- colored endocrine gland, called corpus luteum, formed from an empty Graffian follicle during the pregnancy. The corpus luteum is formed on the nineteenth day of the menstrual cycle. The Grafian follicle is formed after the first meiotic division and before ovulation.
- Reinier de Graaf discovered the follicles of the ovary, known as the Graafian follicle.
- The Graafian follicle is also known by the name of the ovarian follicle.
- The Graafian follicle provides two major functions which are:
1. It is responsible for the maturation of the oocytes and the release of fertilizable oocytes.
2. It is responsible for the formation of the corpus luteum, which helps in the maintenance of embryos.
- Granulosa cells or follicular cells are the cells that surround the oocyte within the follicle.
- The follicular antrum is the portion of an ovarian follicle that is filled with follicular fluid.
- The corona radiata is the granulosa cells that directly surround the oocyte, and are released along with it at ovulation.
- Cumulus oophorus is a cluster of cells (called cumulus cells) that surround the oocyte both in the ovarian follicle and after the ovulation.
- In mammals having an oestrus cycle, the follicle enlarges during the early part of the cycle. The follicle cells divide into two layers, one around the oocyte and the other an external layer, until the follicle bursts on to the surface of the ovary, discharging the oocyte (ovulation).
- The follicles that do not ovulate, degenerate, while the rest forms the corpus luteum.
So, the correct answer is,’Graafian follicle.’

Note: The Graafian follicle contains an oocyte attached to its wall, and responsible for estrogen production in the ovary. The corpus luteum secretes a steroid hormone called progesterone under the influence of the anterior lobe of the pituitary gland.