Human Reproductive System and Gestation in Humans

This article discusses the male and female reproductive systems, fertilization, gestation, and birth in humans. It covers the anatomy and functions of the male and female reproductive organs, the menstrual cycle, oogenesis, spermatogenesis, fertilization, and the stages of fetal development. It also explains the role of hormones during pregnancy and the process of birth. Course code, course name, and college/university are not mentioned.

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Title: Human Reproductive System and Gestation in Humans

Table of contents
Contents
Executive summary..................................................................................................................4
Introduction..............................................................................................................................4
Body.........................................................................................................................................5
Conclusion................................................................................................................................9
References..............................................................................................................................10

Executive summary
The male reproductive system is responsible for producing the male reproductive
gametes, so is the female reproductive system which produces the female reproductive
system. Unlike the male reproductive system, the female reproductive system is found inside
the body. The ova in the female are reproduced by the ovaries (oogenesis) and move through
the fallopian tube on their way to the uterus. Sperms are produced in the testes where they are
also stored. They pass through the sperm duct to the urethra on their way out during sex. A
single ejaculation contains millions of sperms. During copulation, the sperms are released in
the vagina by the penis. They then swim towards the fallopian tube. If they meet the ovum, it
is fertilized otherwise they die. If the ovum is not fertilized, together with the uterine wall,
they are shed as blood (menstruation). If the egg is fertilized, the zygote is implanted on the
uterus as it undergoes meiosis division. The zygote grows into an embryo then a foetus and
then a full grown baby. In the womb, nutrients and gaseous exchange is through the placenta.
After birth, the placenta is cut and the baby can use the lungs for breathing and also feed
through the mouth.

Introduction
The male reproductive system is found outside the body. Its functions include
reproduction, transportation of sperms and semen, then discharging the male reproductive
cells in to the female sex organ and production and secretion of male sex hormones. The
external structure of the male reproductive system include the scrotum, testicles and penis.
The penis is the organ used during sex and is made up of three parts, the root, the shaft and
the glans (Cleverland Clinic, 2016). The urethra, opens at the tip of the penis and is
responsible for transportation of semen and urine outside the body. The scrotum is a skin
pouch like and hangs below the penis. It houses the testicles, blood vessels and nerve
endings. The scrotum maintains the appropriate temperature for the production of sperms.
Body
The testicles also called the testes, are two ball like structures found inside the
scrotum. The testes manufacture sperms and secrete testosterone, the male sex hormone.
Inside the testes are the seminiferous tubules where spermatogenesis occurs. The epididymis
is connected to the vas deferens and carries and store sperms. The seminal vesicles produce
substances like fructose which provide energy to sperms. Prostate gland found just below the
bladder secrete fluid that acts as a nourishment to the sperms during ejaculation. The
Cowper’s gland, found after prostate gland secretes a basic fluid which neutralizes any
acidity along the urethra. The fluid also lubricates the urethra.
According to Lumen (2018), the female reproductive system is made up of two key
parts, the uterus and the ovaries. Other internal parts include the cervix, fallopian tube, vagina
and ovary. The external parts of a female reproductive system are vulva, pudendal cleft, mons
pubis. Labia majora and minora, clitoris and the Bartholin’s gland. The uterus produces
uterine secretions and also the vaginal fluids, it is in the uterus where the fertilized egg

develops in to a foetus. The uterus also allows passage of the male gametes to the fallopian
tube. The uterus can be anatomically into four parts, the corpus, cervix, fundus and internal
os. The ovaries produce the ova, the female reproductive cells. The ovaries are usually two.
They are also responsible for secretion of progesterone and estrogen hormones.
Libia majora (large lips) encloses and provides protection to the female reproductive
parts. Libia minora (small lips) surround the vagina and just inside libia majora. Bartholin’s
gland, found besides the vagina, secretes a fluid that used for lubrication during sex. The
clitoris is a small and sensitive organ in the female reproductive system. It is where the labia
minora meet and is covered with the prepuce (Web MD, 2017). Vagina, also called the birth
canal, connects the cervix.. The fallopian tube or the oviduct connects the uterus with the
ovaries. It is the passage through which the ova travels to the uterus from the ovaries.
Fertilization and conception occurs at the oviduct (Zimmermann, 2018).
Through oogenesis, approximately every month an ovum is released by the ovaries
and send through the oviduct. If the ovum is not fertilized, it then flushes out through
menstruation. Menstruation is the shedding of the uterine wall (endometrium) that occurs
almost every month in women above puberty stage except when pregnant. Menstruation stops
after reaching menopause. The menstruation cycle ranges between 25 to 36 days. This cycle
is regulated by two hormones, the luteinizing hormone and the follicle stimulating hormone.
These hormones are secreted by the pituitary glands and stimulate the ovaries to secrete the
progesterone and estrogen (Knudtson, 2016).
The menstruation cycle has four stages, namely the menstruation, the follicular phase,
ovulatory phase and then luteal phase (Wangari, 2009). The cycle begins with menses where
the women experience nausea, abdominal and back pains. After menses, the pituitary glands
start secreting the follicle stimulating hormone (FSH). The FSH causes the development of

the Graafian follicles and stimulates the secretion of oestrogen which brings about repair and
healing of the uterine wall. Accumulation of the oestrogen stimulates the release of lutenising
hormone (LT) which initiates maturity of the Graafian follicle (Mayo clinic, 2016). The
mature Graafian follicle releases the ovum (a process called ovulation) then turns into a
yellow body, the corpus luteum. The LT stimulates secretion of progesterone which functions
to increase the blood supply and thickening of the endometrium in preparation for
implantation of the blastocyst (Health line, 2018). If fertilization occurs, level of progesterone
increases, blocking the FSH from stimulating maturity of another Graafian follicle. In no
fertilization, the corpus luteum disintegrates and menses occurs (Hawkins & Matzuk, 2008).
Monroy (2017) describes fertilization as the process of union nucleus of paternal and
maternal origin to form a zygote. This process occurs in the fallopian tube after copulation. A
single ejaculation contains millions of sperms but only one fertilizes the ovum. As the ovum
moves in the oviduct, it secretes chemical substances which are neutralized by enzymes
produced by the acrosome before fertilization. The acrosome bursts open as soon as the
sperm comes into contact with the ovum, releasing lytic enzyme which digests the ovum
membrane (Albert, Johnson &Lewis, 2002). The acrosome turns into a filament for
penetrating into the ovum, then the vitelline membrane undergoes changes which hinders any
other sperm from penetrating. The cytoplasm of the sperm cell burst to release the nucleus
which fuses with the female nucleus to form a diploid zygote (Dale, 2013).
During pregnancy, a woman is faced with many changes, physical, known and others
come as a surprise (Nierenberg, 2015). According to Nierenberg 2015 some changes which
come by surprise are enlargement of breasts and varicose veins in the genitals. Women may
experience bleeding gums during pregnancy which exposes them to infections. The increased
level of oestrogen may lead to growth of thicker and healthier hair on the body of the woman.
Some women tend to have stretch marks on their skin. The breasts become more tender and

full with the nipples becoming more sensitive to touch and also darken. There is change in
their body temperature due to increased metabolic reactions.
After fertilization, the zygote undergoes a couple of mitotic divisions as it moves
down and implants on the uterine wall. During the first month of the embryo, the amniotic
sac forms around it. The placenta also develops. Blood vessels and the heart also develop. By
the third month, the foetus has arms and legs. The reproductive organs begin to develop too.
The baby is about 6 inches by the fourth month. The baby has grown muscles and its
movements could be felt by fifth month. Hair starts growing on its head. By the ninth month,
the lungs are almost fully grown, the foetus can blink and respond to any stimuli (Cleverland
clinic, 2014). The placenta is the point of association between the foetus and the mother. It
allows a selective movement of materials, including nutrients, oxygen, antibodies, antigens,
carbon dioxide and metabolic waste, between the mother and the baby. It also allows passage
of drugs and other chemicals in to the system of the foetus, hence it is prohibited to abuse
drugs and substances during pregnancy.
The reduction of progesterone in the mother’s system stimulates release of oxytocin
hormone by the posterior pituitary gland. This is the onset of birth. Oxytocin allows the
myometrium muscles to contract, which occurs in wave to expel the foetus (Kumar &
Magon, 2012). The waves lead to labour pains which are accompanied by dilation of cervix
and rapture of amnion, releasing the amniotic fluid. Contraction of the urine wall spreads
throughout the uterus, pushing the foetus out through the birth canal. After the baby is out,
the umbilical cord is cut to separate the baby from the placenta, which is expelled later (Beck
& Huffman, 2017).
After implantation has occurred, human chorionic gonadotropin, stimulates release of
ovum its development and also it is associated with early pregnancy symptoms like fatigue,

nausea and missing of menses, is produced. The corpus luteum produces large amounts of
progesterone until the tenth week of gestation (Kumar & Magon, 2012). Almost 100 grams of
progesterone are produced between the sixth and eight weeks to support pregnancy. The
progesterone helps prevent preterm labour. It also maintains the functionality of the placenta.
It also causes breast tenderness, heartburns and the pains of the pubic bone. Oestrogen also is
produced by the placenta and helps stimulate the release of progesterone in the last month of
pregnancy (Kafeel, 2011). Other protein hormones such as the placental lactogen, growth
hormone variant, calcitonin and relaxin are used in maintenance of pregnancy.
Conclusion
Therefore, the sperms are the male gametes while ova are the female gametes. They
fuse during fertilization to form a zygote. This fertilization takes place at the fallopian tube or
the oviduct. The zygote is then implanted on the uterine wall where it divides meiotically. It
develops from a zygote to a full grown foetus and is born after nine months. If fertilization
does not take place, the ovum and the uterine wall are shed as blood.

References
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