FETAL DEVELOPMENT PROCESS

FETAL DEVELOPMENT PROCESS


A. Early Biologics 

Fertilization or conception is the process by which sperm and ovum unite to create a single cell called a zygote, which then multiply by cell division repeatedly to make all the cells that form the baby. At birth, a girl believed to have 2 million immature ova in both ovaries, each egg is in a tiny sac or follicle. When an adult who is sexually mature ovulatory follicles mature or destruction at one ovary and ovum loss occurs every 28 days until menopause. Ovum carried through the fallopian tube by tiny hair cells called cilia, to the uterus or womb. And fertilization usually occurs for two or three days in which the ova through the fallopian tubes. 

Sperm produced by the testes or reproductive glands of adult males as much as several hundred million a day and issued in the form of semen when sexual climax. After being in the vagina, the sperm will try to swim through the cervix (mouth of the uterus) and into the fallopian tubes, but only a small proportion who reached that far. Sperm and ova eventually meet and determine the new man will be formed. When the ovum and sperm unite they would lose the baby with genetic structures that affect the characteristics of a broad, ranging from eye color and hair to health, intelligence, and personality. 


B. Multiple births 

Multiple births can occur in two ways: 

1. Dizygotic twin / twin concentric (fraternal twins) is the mother's body produces two ova within adjacent or sometimes one that has not been fertilized ovum splits into two, and both are fertilized ovum. Characteristics are more or less the same as siblings in general and there or a different type. 

2. Monozygotic twins (monozygotic twins) is when a fertilized ovum that has been split into two. The results are identical twins, triplets, quadruplets and other multiple births. These twins have the same innate characteristics and the same gender, but different experiences during their prenatal and postnatal different in some respects. Physical characteristics, such as curly hair, tooth patterns, and the use of the hand, it could be the opposite.



 
C. Genetic Code 

Chromosomes (chromosomes) is a circle of DNA that consists of smaller parts and is called a gene (genes), the functional unit of the default. Every cell in the human body except the normal sex (sperm and ova) have 23 pairs of chromosomes, totaling 46. So when sperm and ovum unite when conception, they produce a zygote with 46 chromosomes, 23 from the father of 23 from the mother. 

After a zygote, the research shows that there is a certain group of genes that are responsible for changing vertebrate creatures, is a gene that produces molecules called morphogens. Morphogen works forming arms, hands, fingers, spine, ribs, brain and other body parts. 

At the time of conception, 23 chromosomes from the sperm and 23 of the ovum to form 23 pairs. A total of 22 pairs are autosomes (autosomes), chromosomes that are not related to sexual expression. Couple that to the 23 is the sex chromosomes (sex chromosomes), one of the father of one of the mothers who determine the sex of the baby.  

A man chromosomes X and Y. Women have two chromosomes are XX. Baby boy received a Y chromosome from father and X from their mothers, while women receive the X chromosome from father and X from the mother. 

D. Developments PreNatal 

The pre-born is divided into three, namely: 

1. Germinal Period (germinal stage) 

The period of prenatal development that occurs at 2 weeks after conception. This includes the formation of a fertilized egg is called a zygote, cell division, and the attachment of the zygote to the uterine wall. Rapid cell division the zygote begins germinal period in approximately 1 week after fertilization, cell division, these cells spesialisai her for specific tasks has begun. At this stage a group of cells called the blastocyst, composed of many cells that will develop into the embryo and trophobalast, the outer layer of cells that develops during the germ. Implantation, zygote attach to the uterine wall, occurs about 10-14 days after conception. 

2. The embryonic period (embryonic stage) 

During the period of prenatal development that occurs from 2-8 weeks after conception. During the embryonic period, the rate of cell division increases, support systems and organs form appears. This period began when blastococyst attached to the uterine wall. The period is now called an embryo cells, and three layers of cells are formed, endodern embryo, ectoderm, and mesodern. When the three layers of the embryo is formed, the life support system for rapidly developing embryo. Life-support system includes the amniotic, umbilical cord, placenta. The organism is a name given to the process of organ formation that occur during the first two months of prenatal development. In the third week of the neural tube eventually form the spine. In about 21 days, the eyes begin to appear, and about 24 days of heart cells begin to separate. During week 4 urogenital system became apparent, and will be the hands and feet appeared. The four chambers of the heart is formed, and visible blood vessels. From week 5 to 8 hands and feet getting separated, now face began to take shape but it is not yet clear. Developing bowel and facial structure looks. After 8 weeks, the developing organism weighs about 1/30 ounce, and only 1 inch long. 

3. Fetal Period (fetal stage) 

Is the period of prenatal development that began 2 months after conception and lasts for 7 months, on average. Three months after conception the fetus is about 3 inches long and weighs about 1 ounce. The fetus was active, moving his head. Face, forehead, eyelids, nose, and chin can not be distinguished, as well as the upper arms, forearms, hands and feet. Sex can be identified at the end of the fourth month, the fetus has grown about 6 inches long, and weighs 4 to 7 ounces. At this very moment arm and leg movements can be felt the first time. 

At the end of five months the fetus is about 12 ins in length and weigh close to 1 pound. Skin structure has been formed, toenails and hands. At the end of the sixth month the fetus is about 14 inches in length to one half pound. The eyes and eyelids are fully formed, and a thin layer of hair covering the head. Grasp reflex appears, and irregular breathing movements occur. At about 7 months, the fetus for the first time have a chance to survive outside the womb, the fetus is able to grow. 

Over the last 2 months prenatal development, growing fat tissue and function of various organ systems, heart and kidneys. At the end of the month to 7, the fetus is about 16 inches long and weighs 3 pounds. During the month 8 and 9, the fetus grows longer and gained considerable weight around 4 pounds.
 

E. Teratology and Factors Affecting Fetal Development 

The general principle teratogen is any substance that causes birth defects. Field of study that examines the causes of birth defects called teratology. Teratogens include medications, blood type does not match, environmental pollutants, infectious diseases, malnutrition, maternal stress, and maternal and paternal age. 

Factors affecting fetal development, among others: 

1. Prescription or non-prescription (antibiotics, antidepressants, diet pills, aspirin, caffeine, etc.) 
2. Drugs - Psychoactive drugs (alcohol, nicotine, cocaine, heroin) 
3. Blood type did not match. 
4. Mother diseases (rubella / measles, syphilis / sexually transmitted disease, herpes, AIDS) 
5. Diet and Nutrition mother. 
6. Stress and emotional state of the mother 
7. Maternal age 
8. Factors father

• Just like mom, under the influence of drugs, disease, nutrition, emotional state, age.

• Contact men with tin, radiation, some pesticides, and petrochemicals

• Father smoker

9. Environmental Hazards (radiation, toxic waste, and environmental pollutants and toxic waste) 
To know more detail about the factors that affect fetal development reopen book development 


REFERENCE: 

1. Papalia Olds Feldman, Human Development, Salemba Humanika,(Jakarta;2009).
2. John W. Santrock, Perkembangan Anak, Erlangga,(Jakarta;2007)





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