The document summarizes prenatal development from conception to birth, which encompasses three main stages: the germinal stage, embryonic stage, and fetal stage. It describes the key events that occur during each stage, such as fertilization, implantation, formation of the three germ layers, and the growth and development of organs. The document also discusses potential physical, psychological, genetic, and environmental hazards to prenatal development, including maternal stress, drug use, disease, nutrition, and environmental toxins.
2. How life
begins.
New life begins with the union of a
male sex cell (spermatozoon) and a
female sex cell (ovum). Development
begins with conception. All of the other
cells in your body developed from this
single cell. Each cells contains
enduring messages from the parents
carried on the chromosomes. Each
chromosome houses many genes.
Within the genes is a substance known
as DNA (deoxyribonucleic acid).
3. Periods of
prenatal development
The prenatal period extends from
conception to birth, usually
encompassing nine months of
pregnancy. Development during the
prenatal period is remarkably rapid.
It is divided into three stages: (1) the
germinal stage, (2) the embryonic
stage, and (3) the fetal stage.
4. The Germinal Stage
The germinal stage is the first phase of
prenatal development, encompassing the
first two weeks after conception. This stage
begins when a zygote is created through
fertilization. Within 36 hours, rapid cell
division begins, and the zygote becomes
microscopic mass of multiplying cells. The
first cell division is called blastocyst. On the
seventh day, the cell mass begins to implant
itself in the uterine wall, this process is called
implantation.
5. The Embryonic Stage
The embryonic stage, lasts from two weeks
until the end of the second month. Once the
placental circulation is in place; nutrients,
oxygen, vitamins, and water in the mother’s
blood stream pass through the placenta and
umbilical cord to the developing organism,
which is called embryo.
The embryo forms into three germ layers which
give rise to different organs and tissues. The
mesoderm forms the skeletal, muscle, skin, and
lymphatic system. The endoderm forms the
respiratory system, stomach, colon, liver,
pancreas, urinary system thyroid and
parathyroid . The ectoderm forms the central
and peripheral nervous system.
6. The Fetal Stage
The fetal stage of the fetus is the third stage of
prenatal development, lasting from two months
through birth. Early in this stage muscles and
bones begin to form. Fetus becomes capable of
physical movements as skeletal structures
harden. Organs formed in the embryonic stage
continue to grow and gradually begin to
function. Sex organs start to develop during the
third month. Approximately the end of the sixth
month, the fetus attains viability.
8. Common Physical Hazards During the Prenatal Period
Fetal Stage
Germinal Stage -Miscarriages
-• Starvation Embryonic Stage
- Miscarriage - Prematurity
-•Lack of uterine
- Developmental - Complications of
preparation
irregularities. delivery
-•Implantation in
- Developmental
the wrong place.
irregularities.
9. Psychological Hazard
Traditional
Maternal stress
beliefs about
during the
prenatal
prenatal period.
development.
Unfavorable
attitudes toward
the unborn child.
11. Down Syndrome
Also known as trisomy21, Down syndrome
Inherited Diseases
Sex-Chromosomescommon illness can be inherited if one
is the most Problems anomaly
A number of genetic
A third type of genetic prenatal development. Down
during problemsparents carries a gene for the
or both involves
syndrome These include
is caused by and extra copy of
sex-chromosomes. disease. Examples of inherited diseases
conditions such as Klinefelter’s syndromeanemia, Cystic fibrosis,
the 21 chromosome (meaning there are
include Sickle-cell
(an extra X-chromosome) and turner of usual two) tests can
three chromosomes instead
and Tay-Sachs disease. Genetic
syndrome (a single X-chromosome). 1 out of every
and impact approximately if a parent is a carrier of
often determine
1000 infants. Typical features of down
genes for a specific disease.
syndrome include flattened facial features,
heart defects, and mental retardation. The
risk of having a child with Down syndrome
increases with maternal age.
13. Maternal Drug Use
Maternal Disease
The use of substances by the mother
canThere devastating consequences to
have are a number of maternal
the fetus. Smoking is linked to low birth
disease that can negatively impact the
Maternal Nutrition
weight, which canherpes,in a weakened
fetus, including result rubella, and
The developing fetus needs a variety of
immune system, poor one of the most
AIDS. Herpes virus is respiration, and
essential nutrients . Effects of severe
common maternal diseases and can be
neurological impairment. Alcohol use
malnutrition can be poor motor skills,
can lead fetal alcohol syndrome, which
transmitted in the fetus, leading to
apathy, and irritability during infancy. It
deafness, brain swelling, or body
is linked to heart defects, mental
is important for pregnant women to
malformations, and mental retardation.
retardation. Women with herpes virus
have nutritionally balanced diets.
The use of encouraged to deliver via
are often illicit drugs such as cocaine
and methamphetamine is also linked to
cesarean to avoid transmission of the
low birth weight and neurological
virus.
impairment.