Question

What is spermatogenesis? Briefly describe the process of spermatogenesis.​

Answer 1

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The phenomena of sperm production from the immature germ cell in males is termed as spermatogenesis. The process occurs in the seminiferous tubules located inside the testes. In this process, a diploid male germ cell or spermatogonium enlarges (in size) for the formation of a diploid primary spermatocyte which inturn goes through the first meiotic division or meiosis I.

This division is a reductional division for the formation of two equal haploid secondary spermatocytes, each of which further undergoes second meiotic division of meiosis II for the formation of two equal haploid spermatids.

Subsequently, four haploid spermatids are formed from a diploid spermatogonium. The spermatids hence produced alter to form spermatozoa(sperm) through the process of spermiogenesis.

Answer 2

Definition

They produce male gametes called spermatozoa by the process of spermatogenesis.  

Process:

Spermatogenesis is the process by which haploid spermatozoa develop from germ cells in the seminiferous tubules of the testis. This process starts with the mitotic division of the stem cells located close to the basement membrane of the tubules.[1] These cells are called spermatogonial stem cells. The mitotic division of these produces two types of cells. Type A cells replenish the stem cells, and type B cells differentiate into primary spermatocytes. The primary spermatocyte divides meiotically (Meiosis I) into two secondary spermatocytes; each secondary spermatocyte divides into two equal haploid spermatids by Meiosis II. The spermatids are transformed into spermatozoa (sperm) by the process of spermiogenesis. These develop into mature spermatozoa, also known as sperm cells.[2] Thus, the primary spermatocyte gives rise to two cells, the secondary spermatocytes, and the two secondary spermatocytes by their subdivision produce four spermatozoa and four haploid cells.[3]

Spermatozoa are the mature male gametes in many sexually reproducing organisms. Thus, spermatogenesis is the male version of gametogenesis, of which the female equivalent is oogenesis. In mammals it occurs in the seminiferous tubules of the male testes in a stepwise fashion. Spermatogenesis is highly dependent upon optimal conditions for the process to occur correctly, and is essential for sexual reproduction. DNA methylation and histone modification have been implicated in the regulation of this process.[4] It starts at puberty and usually continues uninterrupted until death, although a slight decrease can be discerned in the quantity of produced sperm with increase in age (see Male infertility).

Spermatogenesis starts in the bottom part of seminiferous tubes and, progressively, cells go deeper into tubes and moving along it until mature spermatozoa reaches the lumen, where mature spermatozoa are deposited. The division happens asynchronically; if the tube is cut transversally one could observe different maturation states. A group of cells with different maturation states that are being generated at the same time is called a spermatogenic wave.[5]