Question

Name the organs where gametogenesis gets completed in human males and females respectively?

Answer 1

Humans are sexually reproducing and viviparous organisms. When they reproduce, they include the formation of gametes (gametogenesis), i.e., sperms in males and ovum in females, respectively, and then occurs the transfer of sperms into the female genital tract (insemination) and after that there occurs fusion of male and female gametes (fertilization) leading to the formation of zygote.

Complete answer:
The formation and production of male gamete are known as spermatogenesis.
Spermatogenesis:
In testis, the immature male germ cells, spermatogonia produce sperms by process spermatogenesis that begins at puberty. Spermatogenesis occurs in four stages: (i ) Spermatocytogenesis, (ii) Meiosis-l (iii) Meiosis-II and (iv) Spermiogenesis.
Spermatocytogenesis: In spermatocytogenesis, the spermatogonia remains attached to the inside wall of the seminiferous tubules multiply by mitotic division and multiply in numbers. Some spermatogonia changes in their structure as they grow, increase in size by assimilating nourishing materials, and are called primary spermatocytes which periodically undergo meiosis and others remain as spermatogonia.
Meiosis-1: A primary spermatocyte is diploid, (2n) with 44 + XY (total 46) chromosomes. It undergoes the first meiotic division (reduction division) and after completion, it is leading to the formation of two equal, haploid cells called secondary spermatocytes,
Meiosis-ll: The secondary spermatocytes undergo the second meiotic division to produce four equal, haploid spermatids.
Spermiogenesis: Transformation of spermatid into sperm is termed spermiogenesis.
The formation of female gamete is known as oogenesis.
Oogenesis:
The process of formation and generation of a mature female gamete is called oogenesis which is markedly different from spermatogenesis. Oogenesis is started at the time of the embryonic development stage when a couple of million gamete mother cells (oogonia) are formed within each fatal ovary, no more oogonia are formed or added after birth. Scattered ovarian follicles are embedded in the stroma of the cortex.
An ovarian follicle consists of an oocyte, surrounded by one or more layers of follicular (flat epithelial) cells, the granulosa cells, which are derived from the germinal epithelium lining the ovary. The oogonial cells start division and enter into prophase-l of the meiotic division, and get temporarily arrested at this stage called primary oocytes. Each primary oocyte gets surrounded by a layer of granulosa cells and then called a primary follicle.
A large number of primary follicles degenerate from birth to puberty that is at the age of 14-16. Degeneration and disintegration of ovarian follicles are called follicular atresia and their disposal is done by phagocytes. Thus, at the time of puberty, only 60,000 to 80,000 primary follicles are left in each ovary.
So, the formation of a female gamete takes place in the ovary and a male gamete takes place in the testes.

Note:
The primary sex organs - the testis in the males and the ovaries in the females, produce gametes i.e. sperms and ovum respectively, by the process called gametogenesis. The ovary is the primary female sex organ. It produces ova and secretes the female sex hormones, estrogens, and progesterone which is responsible for the development of secondary female sex characters.