beginning of the Child’s Life

beginning of the Child’s Life

Casiño, Lesley Paige F.

July 6, 2012

Prenatal Development

Conception occurs when a sperm fertilizes an ovum creating a one-celled being called a Zygote.

Zygote contains all the genetic materials-half from each of the two gametes.



Three main periods in the growth process from a zygote to a fully developed baby:

•The Germinal Period -- first Two weeksoCharacterized by Rapid Cell

Development . The cell divides into 2, 4 8 and so on.


• Followed by Differentiation wherein the cell multiplies into hundreds and separate into two distinct masses. The outer cells forming a protective circle will be now called the Placenta. And inner cells forming a nucleus will become the Embryo.


• Outer cells have to achieve Implantation. In this process, the embryo plant themselves into the lining of the uterus for nourishment and protection during growth.


• After the implantation, that marks the end of the rapid growth and most dangerous transition of the whole life span and the beginning of the woman’s interaction with her future child.


• Early interaction between the mother and future child includes:– Maintaining a healthy diet– Good nutrition and– Getting prenatal care

Prenatal Developmentthe Period of the Embryo

Embryonic disk consists of three layers:• Ectoderm – outer layer

will become the skin and the nervous system

• Mesoderm – The middle layer will become the muscles, bones, circulatory system,excretory and reproductive system


• Endoderm – the inner layer will become key elements of the digestive system and respiratory system.


During this period, growth proceeds in two directions:– Cephaloclaudal – the

sequence of the body growth and maturation from head to foot

– Proximodistal – the sequence of the body growth and maturation from the spine toward the extremities.


Following this pattern, in the fourth week:– Head and blood vessels begin

to develop– The primitive heart begins to

beat making the cardiovascular system the first organ system to function

– End of the first month,-- eyes, ears, nose, mouth start to form.


Five weeks after conception following the proximodistal sequence:– Upper arms then forearms,

the hands and the fingers appear, legs, feet and toes. At the end of the second month, the originally webbed fingers and toes are already separated.


After eight weeks,– the embryo weighs about

1/30 of an ounce and is about 1 inch long.

– Head becomes more rounded and features of the face are fully formed.

– Embryo has basic organs except sex organs.

Prenatal Developmental

The Period of the Fetus

Trimester• Is called to the three month

long segment of pregnancy.


• First Trimester– first three months of

pregnancy. Basic body structures and organs begin to form.

• Second trimester– Fourth to sixth months.

Time for the essential organs and brain maturation that makes survival possible.


• Third Trimester– Seventh to birth. Period of

final prenatal maturation.

Science of Genetics

The science of genetics is the study of Heredity. It is the inborn factors inherited from the biological parents that affect development.

Science of Genetics

Deoxyribonucleic acid or DNA is a basic of heredity. The structure of DNA resembles a long, spiraling ladder made of four chemical units called BASES.

SCIENCE of GEnetics

The bases and initials are:– Adenine– Thymine– cytosine– guanine

These pair up in four combinations.

At, ta, cg and GC.The sequence of three billion base

pairs constitute the genetic code.

SCIENCE of genetics

Within each nucleus are CHROMOSOMES, coils of DNA that carries the genes, small segments of DNA located in definite position on particular chromosomes.

The complete sequences of mapping of genes in the human body, their locations consitute the human genome.

SCIENCE of genetics

At conception, the 23 chromosomes from the sperm and the 23 chromosomes from the ovum form 23 pairs.

Science of genetics

Twenty-two pairs are called autosomes. These are chromosomes that are not related to sexual expression. The 23rd pair are the sex chromosomes.

Science of genetics

Sex chromosomes are either X or y chromosome. The ovum carries the X chromosome while the sperm carries either the X or y chromosome. The y chromosome contains the gene for maleness called SRy gene.

Science of Genetics

Ovum + X-carrying sperm is a Female -- XX

Ovum + y-carrying sperm is a Male -- Xy

Science of genetics

The foundation for the understanding of pattern inheritance was laid by the Australian Monk, Gregor Mendel.

According to him, there are two types of inheritance:– Dominant– recessive

SCIence of Genetics

The ability or inability to twist both hands and place them at your back are called ALLELES. When both alleles are the same, the person is homozygous and the exact opposite are called heterozygous.

Science of genetics

Dominant inheritance – when a person is heterozygous for a particular trait, the dominant allele governs.

Recessive inheritance – the expression of a recessive trait occurs only when a person receives two recessive alleles, one from each parent.

Science of genetics

Condominance occurs when neither of two alleles is dominant and the resulting trait reflects the influence of both.

Science of genetics

Polygenic inheritance is the interaction of several genes.

Example: Skin color is the result of three of more sets of genes on three different chromosomes.

Science of genetics

Multifactoral transmission is a combination of heredity and environmental factors which plays a role in the expression of most traits.

Science of genetics

Many disorders arise when an inherited predisposition interacts with an environmental factor either before or after birth.

ADHD is thought to be transmitted multifactorially.

Science of genetics

In sex-linked inheritance, certain recessive disorders linked to genes on the sex chromosomes show up differently in male and female children.

Science of genetics

Some children are born with chromosomal abnormalities or disorders. Some are inherited, others result from accidents during prenatal development. Examples are the Klinefelter syndrome and the Turner syndrome.

Science of genetics

Down syndrome, the most common is found in about one third of all cases of moderate to severe mental retardation. It is usually caused by an extra 21st chromosome or the translocation of the part of the 21st chromosome.

Thank you!

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beginning of the Child’s Life