Question

Select the correct statements regarding oogenesis.
(i) It is initiated during the embryonic development stage when millions of oogonia are formed within each ovary.
(ii) Graafian follicle releases primary oocyte from the ovary by ovulation.
(iii) At puberty, only 60,000 - 80,000 primary follicles are left in each ovary.
(iv) Secondary oocyte within tertiary follicles grows in size and completes its second meiotic division.

A) (i), (ii) and (iii)
B) (i) and (iii)
C) (ii) and (iv)
D) All of the above

Answer 1

Hint: Ovulation is the process by which the Graafian follicle releases the secondary oocyte from the ovary. The primary oocyte expands and completes its initial meiotic division inside the tertiary follicle.

Complete Step by Step Answer:
Oogenesis is the process by which ova, usually referred to as female gametes, are produced. The female gamete that results is also known as an ovum. Female gametes are generally referred to as eggs, but because the word "egg" can refer to different developmental phases, the meaning of an egg differs depending on the type of creature.
Different stages of oogenesis are:
Pre natal Stage
While in meiosis-I arrest, the main oocyte develops. In order to create a stratified cuboidal epithelium, the follicular cells multiply. Granulosa cells are the name for these cells. In order to create zona pellucida around the main oocyte, these cells produce glycoproteins.
Antral stage
A central fluid-filled gap known as the antrum is created by the fluid-filled region that exists between granulosa cells. The term "secondary follicles" refers to them. These secondary follicles form during every monthly cycle under the guidance of follicle-stimulating hormone and luteinizing hormone.
Pre ovulatory stage
Meiosis-I finishes at this stage, which is brought on by an increase in LH. Within the follicle, two haploid cells of different sizes are created. A polar body develops in one of the daughter cells that receives less cytoplasm. This cell is not involved in the development of the ovum. The secondary oocyte is the name for the other daughter cell. During meiosis-II, the two daughter cells take part. The secondary oocyte is stopped in the metaphase of meiosis-II while the polar body divides to produce two polar bodies.
Hence, option B is the correct answer.

Note: During the period from birth to puberty, a significant number of primary follicles degenerate. So each ovary has between 60,000 and 80,000 primary follicles during puberty, which are created by the mitotic division of the germ cells.