Human Reproduction: Spermatogenesis, Fertilization & Development

This report provides a detailed overview of the male reproductive system, focusing on the process of spermatogenesis and fertilization. It begins by describing the structure of the male reproductive system, including the testes, spermatic ducts, accessory glands, and external genital organs, emphasizing the roles of the penis, scrotum, testicles, epididymis, vas deferens, prostate, and seminal vesicles. The report then analyzes spermatogenesis, explaining how sperm cells develop from spermatogonium due to hormonal stimulation, and mature in the epididymis. Furthermore, the report elucidates the process of fertilization, detailing how sperm penetrates the oocyte, leading to the formation of a zygote, and outlines the stages of development, including the pre-embryonic, embryonic, and foetal periods, highlighting key events such as cleavage, implantation, gastrulation, organogenesis, and the functioning of organ systems. Desklib provides access to this document and many other resources for students.

Running head: REPRODUCTIVE SYSTEM
REPRODUCTIVE SYSTEM
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Author Note:

1REPRODUCTIVE SYSTEM
Answer No. 1:
The male reproductive system structure consists of gonads (testes), spermatic ducts
(epididymis, vas deferens and ejaculatory ducts), accessory glands (seminal vesicles, prostate
gland, bulbourethral glands) and external genital organs (scrotum and penis). The penis is the
sexual organ that lies externally, above the scrotum and blow the umbilicus. The major
function of penis is to deliver semen in to the vagina during coitus. The scrotum is the thick-
skinned sack like organs that surrounds and protects the testes. When temperature drops
below the optimum condition for spermatogenesis, it contracts to pull the testes closer to the
body for protection and warmth. The testicles are involved in production of sperms and
testosterone. The epididymis is a sperm storage zone lying against each testis. The vas
deferens is a firm tube structure that transports sperm from the epididymis. The prostate lies
just below the bladder and surrounds the urethra, contributing to the fluid that makes up the
sperm. The seminal vesicles located above the prostate, produce fluid that nourishes the
sperm (Shier, Butler and Lewis 2017).
Male reproductive system structure; Source: Shier, Butler and Lewis 2017
The process of spermatogenesis occurs in the testes and epididymis which is
responsible for producing sperms. This occurs in adult males since before puberty there is no

2REPRODUCTIVE SYSTEM
hormonal stimulation for spermatogenesis. With the onset of luteinizing hormone (LH) and
follicle stimulating hormone (FSH) production, spermatogenesis begins. Maturation of germ
cells occurs due to triggering of FSH and LH triggers the production of testosterone by the
testes. The stem cells present in the lobules of testes called spermatogonium develops in to
the sperm cells due to stimulation of the testosterone. Through meiosis I the spermatocyte
divides into two haploid secondary spermatocytes. Meiosis II forms four
haploid spermatid cells. Then by spermiogenesis the sperm head and the
flagellum develops. This is now called the spermatozoa. The spermatozoa
is released into the epididymis where it maturation completes and it
becomes ready to move on its own (Simpson 2018).
Spermatogenesis; Source: Simpson 2018

3REPRODUCTIVE SYSTEM
Answer No. 2:
The process of fertilization combines the sperm with an oocyte of
an egg cell that is produced by the female reproductive system. This
combination of the sperm and the oocyte form the fertilized zygote. In
order to reach the oocyte, the sperm must swim through the vagina and
the uterus to get entry into the fallopian tube where the oocyte is present.
In order to fertilize, the sperm must penetrate the walls of the oocyte. The
outer covering of the oocyte consists of the corona radiata and zona
pellucida layers. In the head region of the sperm an enzyme called
acrosome is present which helps the sperm to penetrate the outer layers
of the oocyte. After penetration, it fuses with the nucleic of the haploid
cells present in the interior of the oocyte. This fusion gibes rise to a diploid
cell which is called the zygote. The zygote then begins to divide forming
the embryo (Fowler et al 2013).

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Fertilization process; Source: Fowler et al 2013.
The development period is divided in three major stages namely
the pre-embryonic stage, the embryonic stage and the foetal period. The
pre-embryonic stage includes fertilization followed by cleavage,
implantation and gastrulation. This stage lasts for around two weeks. The
next is the embryonic stage which starts from the 3rd week. It consists of
organogenesis and formation of support structures like placenta, umbilical
cord and the extra-embryonic membranes. The last is the foetal period
which extends from the 9th week to the 38th week. During this period, the
organs start to function and works in coordination to form the organ
system. This marks the end of the pre-natal development periods and the
birth of the baby takes place (Citruscollege.edu 2018).

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Development before implantation; Source: Citruscollege. edu.2018
References
Citruscollege.edu.2018. [online] Available at:
http://www.citruscollege.edu/lc/archive/biology/Documents/KondoNotes/lewis_ch40.pdf
[Accessed 11 Jun. 2018].
Fowler, S., Roush, R., Wise, J. and Stronck, D., 2013. Concepts of Biology. Openstax
College, Rice University.
Shier, D.N., Butler, J. and Lewis, R., 2017. Hole's essentials of human anatomy &
physiology. McGraw-Hill Education.

6REPRODUCTIVE SYSTEM
Simpson, M.L., 2018. Human anatomy & physiology. Biol.