A Comprehensive Biology Report on Human Reproduction and Development

This report provides a detailed overview of human reproduction, beginning with the fundamental concept and encompassing various aspects of the process. It explores the roles of hormones in different stages of pregnancy, including Human chorionic gonadotropin hormone (hCG), Human placental lactogen (hPL), Estrogen and Progesterone. The report then delves into fertilization, explaining the union of sperm and egg. Key changes in females during pregnancy, such as alterations in the respiratory, cardiovascular, and gastrointestinal systems, are discussed. The report also outlines the stages of fetal development within the womb, from conception to birth. The importance of the placenta in providing nutrition to the baby is highlighted, followed by a description of the events of birth and the changes a baby undergoes after birth. The report concludes by summarizing the key findings and referencing relevant journals, books, and online resources.

REPRODUCTION
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TABLE OF CONTENTS
INTRODUCTION...........................................................................................................................3
1. The hormone's role in different stages of pregnancy...............................................................3
2. Fertilization..............................................................................................................................4
3. Key changes in females during pregnancy .............................................................................4
4. Fetus development in the womb..............................................................................................5
5. Importance of the placenta.......................................................................................................6
6. Events of birth..........................................................................................................................6
7. Changes in baby after its birth.................................................................................................6
CONCLUSION ...............................................................................................................................7
REFERENCES................................................................................................................................8
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INTRODUCTION
The concept of reproduction is regarded as biological procedure through which
production of the new individual organism- offspring is done from their parents. In other words
reproduction can be considered as the fundamental feature of all known life, the existence of
every individual organism is as a result of reproduction (Teerds, De Rooij and Keijer, 2011). In
the present study reproduction has been discussed. The report includes role of hormones in every
stage of pregnancy. Further it involves key changes in females during pregnancy.
1. The hormone's role in different stages of pregnancy
There is a significant impact on various hormones level present in the body during
pregnancy some of them plays an important during the pregnancy period. This is comprised of
follows: Human chorionic gonadotropin hormone (hCG): This hormone is present in placenta and
only produced during the period of pregnancy During the first trimester of pregnancy
period, the level of this hormone gets increased drastically in the blood and urine of the
mother and this has made contribution in causing nausea as well as vomiting that is
attached to pregnancy. Human placental lactogen (hPL): Placenta produce this hormone. It assists in the
procedure of giving nutrients to fetus as well as have effective role in stimulation of milk
glands within breasts in anticipating breastfeeding (Alvergne and Lummaa, 2010). Estrogen: This hormone is responsible develop the various sexual characteristics in the
females. It develops in ovaries, placenta produces estrogen while pregnancy for
maintaining a healthy pregnancy.
 Progesterone: Ovaries and placenta produces this hormone during the pregnancy period.
Progesterone stimulate to thicken the uterine lining within anticipation of implanting of
fertilized egg (Müller, Hassel and Grealy, 2015).
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2. Fertilization
Fertilization in human is regarded as union of human egg as well as sperm. This is
emerging in ampulla of the fallopian tube. The union results in production of the zygote cell or
the fertilized egg that initiates parental development. The procedure of the fertilization includes a
sperm fusing in an ovum. The most common sequence starts with ejaculation during copulation
that is followed with ovulation and ends with the fertilization.
3. Key changes in females during pregnancy
Pregnancy is regarded as the time of greater physical as well as emotional changes within
women. Everything including size of belly to the speed at which the heart is beating changes
over the period of nine months resulting in the childbirth. The pregnant women body undergoes
several normal changes that are quite subtle (Parham and Moffett, 2013). These alterations are
important for assisting in the fetal development and prepares the body towards labor. Some of
the changes are as below: Changes in respiratory system: The rate of respiratory increases to compensate towards
increasing maternal oxygen consumption, it is demanded by uterus, placenta and the
fetus.
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 Changes in cardiovascular system: While pregnancy the whole cardiovascular system is
readjusted, blood volume enhances to greater extent. Further there is growth in more
blood vessels and also the pressure of expansion of uterus on larger veins leads to causing
the blood towards slowing down while return to the heart. Alteration in gastrointestinal system: There is enlargement of the uterus there is rise up
and put in relation with pelvic. Abdomen changes activity: Such displaces stomach, intestines as well as other adjacent
organs. Changes of the breasts: Breasts become larger and highly tender as a result in increasing
levels of hormones estrogen as well as progesterone. With the emergence of due date
hormone alters that results in causing breasts of women to get even bigger in order to
prepare for breastfeeding (Moffett and Colucci, 2015).
 Abdomen changes: There is expansion of abdomen. A pregnant woman's abdomen can
ache as abdominal wall as well as ligaments which are assisting the uterus are stretched.
4. Fetus development in the womb
The fetus development within the womb is done in stages. These are as under: Conception: This is when fertilization takes place when meeting of the sperm penetrates
an egg in the mother's body. Here at this stage the genetic make up is finished including
the baby's sex. Development in 4 weeks: At this stage the baby is making development of structure that
eventually forms its face and neck. The heart and blood vessels continues towards
development. Development in 8 weeks: At this the baby is small that is half an inch in size. Development at 12 weeks: At this stage, the baby measures about 2 inches and starts
making movements in the mother's womb. Development in 16 weeks: Here the baby measures 4.3 to 4.6 inches and weight is about
3.5 ounces. Development at 20 weeks: At this stage the weigh of the baby is 10 ounces and it is little
more than 6 inches long (Croft and et.al., 2015).
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 Development at 28 weeks: The baby weighs about 2 pounds, 6ounces and start changing
its position at this point of time within pregnancy period (Body changes during
pregnancy, 2017). Development at 36 weeks: The size of the baby differ depending upon several factors.
This can include gender, the number of babies carried out and parents size.
 Birth: A mother's due date is marked as the end of 40th week. The delivery date is being
calculated through the first day for her last period.
5. Importance of the placenta
The greater importance of placenta within pregnancy is towards offering the baby with
enough of the nutrition. This weigh around one sixth of the weight of the new born. It does not
have nerve cells nor this is under the direct control of the spinal cord or the brain. Every minute
almost about 550 milliliters of the blood is being pumped into the uterus for exchanging of the
adequate nutrients in the placenta of the baby in pregnancy (Ziomkiewicz and et.al., 2016).
Placenta is regarded as effective organ that has critical role within pregnancy towards keeping
the baby alive and well. It main function is towards supplying baby with sufficient amount of
nutrition.
6. Events of birth
The event of birth occurs in three stages: First stage: The neck of the womb that is cervix gradually gets opened due to the
contractions. This is comprised of early labour, active labour as well as transitional phase
(Hormones During Pregnancy, 2017). Second stage: It is when expecting mother push baby out into the world.
 Third stage: This is when delivery of the placenta is being done.
7. Changes in baby after its birth
Various changes in the body of the baby takes place occurs in the lungs and circulatory
system of the childt after its birth. This includes increase in oxygen within lungs causing a
decline in the flow of blood resistance to the lungs (Haouzi and et.al., 2010). Further it includes
amniotic fluid drains or absorbed from the respiratory system. Moreover there is increase in
blood flow resistance of baby's blood vessels. These are considered essential for survival of
baby.
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CONCLUSION
It can be concluded from the present study that there are several hormonal changes that
occurs within women during the pregnancy. Further the development of foetus in womb is done
in several stages which at the end leads to birth of new born.
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REFERENCES
Journals and Books
Alvergne, A. and Lummaa, V., 2010. Does the contraceptive pill alter mate choice in humans?.
Trends in Ecology & Evolution. 25(3). pp.171-179.
Croft, D. P. and et.al., 2015. The evolution of prolonged life after reproduction. Trends in
ecology & evolution. 30(7). pp.407-416.
Haouzi, D. and et.al., 2010. Controlled ovarian hyperstimulation for in vitro fertilization alters
endometrial receptivity in humans: protocol effects. Biology of reproduction. 82(4). pp.679-
686.
Moffett, A. and Colucci, F., 2015. Co‐evolution of NK receptors and HLA ligands in humans is
driven by reproduction. Immunological reviews. 267(1). pp.283-297.
Müller, W., Hassel, M. and Grealy, M., 2015. Development and reproduction in humans and
animal model species. Springer.
Parham, P. and Moffett, A., 2013. Variable NK cell receptors and their MHC class I ligands in
immunity, reproduction and human evolution. Nature Reviews Immunology. 13(2). pp.133-
144.
Teerds, K. J., De Rooij, D. G. and Keijer, J., 2011. Functional relationship between obesity and
male reproduction: from humans to animal models. Human reproduction update. 17(5).
pp.667-683.
Ziomkiewicz, A. and et.al., 2016. Evidence for the cost of reproduction in humans: High lifetime
reproductive effort is associated with greater oxidative stress in post-menopausal women.
PloS one. 11(1). p.e0145753.
Online
Body changes during pregnancy. 2017. [Online]. Available through:
<http://www.healthline.com/health/pregnancy/body-changes-infographic>. [Accessed on 26th
May 2017].
Hormones During Pregnancy. 2017. [Online]. Available through:
<http://www.stanfordchildrens.org/en/topic/default?id=hormones-during-pregnancy-85-
P01220>. [Accessed on 26th May 2017].
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