Human growth and development
Name
DPSY 8573 - Child and Adolescent Health
2022
Introduction
The process of prenatal development occurs in three main stages the first two weeks after
conception are known as the germinal stages. The third through the eight week are as the
embryonic period and the time from the ninth week until birth is known as the fetal period.
1) The germinal stage
The germinal stage begins with conception, when the sperm and egg cell unite in one of the two
fallopian tubes. The fertilized egg known as the zygote, then moves towards the uterus, a journey
that can take up to a week to complete. Cell division begins approximately up to 24 to 36 hours
after conception. Within just a few hours after conception the single celled zygote begins making
a journey down to fallopian tube to the uterus where it will begin the process. The zygote first
divides the two cells, then into four, eight sixteen and so on. once the eight cell has been reached
the begin to differentiate and taker on certain characteristics that will determine the type of cells
they will eventually become as the cells multiply, they will also separate into two distinctive
masses, the outer cell will eventually become the placenta while the inner cells will form the
embryo. Cell division continues at a rapid rate and the cells then develop into what is known as
blastocytes
1) the ectoderm-which will become the skin and the nervous system
2) the endoderm- which will become the digestive and the respiratory system
3) The mesoderm-which will became the muscle and the skeletal system.
Finally the blastocytes aligns to the uterus and attached to the uterine wall a process known
implantation.
2) The embryonic stage
The mass of cells is now known as the embryo. The beginnings of the third week after
conception marks the start of the embryonic period time when a mass of cells becomes a distinct
human bring. The embryo begins to divide into three layers each f which will become an
important body system. Approximately 22 days after conception. The neural tube forms this tube
will later develop into central nervous system including the spinal cord and brain.
Around the fourth week the head begins to form quickly followed by the nose, mouth, ears and
eyes. The cardiovascular system is where the earliest activity begins as the blood vessels that will
become he to pulse .during the fifth week buds that will form the arms and legs appears .by the
time it reaches the eight week of development, the embryo has all the basic organs and parts
except those f the sex organs. It even has knees, elbows at this point the embryo weight is just 1
gram and is about 1 inch in length.
4) The fetal stage
One cell differentiation is mostly complete the embryo enters t h
next stage and becomes fetus. This period of development begins during the ninth week and lasts
until birth. The early body system and structures established in the embryonic stage continues to
develop. The neural tube develops into the brain and spinal cord and neurons form sex. Organs
begin to appear during the third month of gestation. The fetus begins to grow in both length and
weight although the majority of the physical growth occurs in the later stages of pregnancy. The
stage of prenatal development lasts the longest and is marked by amazing change and growth.
During the third months of gestation the sex organ begins to differentiate and by the end of the
months of parts of the body the will be formed. At this point fetus weight will be around three
ounces.
The end of the third months also marks the end of the first trimester of pregnancy. During the
second trimester or months six heartbeat grows stronger and other body system stronger
develops fingernails, eyelashes and toenails form perhaps form perhaps most noticeable, the
fetus increases quite dramatically increasing about six tines in size. The brain and the central
nervous system become responsive during the second trimester. Around 28 weeks the brain starts
to mature much faster which activity that resembles that of a sleeping new born.
During period from seven months until birth, the fetus continues to develop, put on weight, and
prepare for life outside the womb. The lung begins to expand and contract preparing the muscles
for breathing.
While a prenatal development usually follows this normal pattern there are times when problems
or dereliction occur.
References
1. William’s. Williamson (1976) decisions in philosophy of religion. Columbus Ohio
Charles e. merlc publishing company
2. John. S. Mbiti (1990) introduction to African religion Nairobi. East African educational
publishers limited.
3. Charles .s. Braden (1954) the religion New York. Abingdon press.
