How does conception occur?
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A women of child-bearing age ovulates once a month during her reproductive years. Ovulation culminates in the liberation of an egg, which then settles in one of the fallopian tubes. There the egg sits and plays a waiting game, as it has but twenty-four hours or so to become fertilized by a sperm. If that happens then the genesis of human life is initated! |
Semen from a male counterpart is a mixture of sperm (produced by the testes) and nourishing and supporting fluids from various accessory reproductive glands, such as the prostate and Cowper’s gland. Ejaculation produces about one-half teaspoon of semen, which will contain millions of sperm. This high number of sperm is very important because the task at hand is so great. Ultimately, however, only one sperm will fertilize the egg and initiate the genesis of human life.
What happens early on in pregnancy?
The fertilized egg now develops into a zygote, which is the very basis of human life. All humans begin their lives as a single cell. This single cell now has combined the genetic information (DNA) from the mother and father and can develop into a complex cell orchestration of metabolism, movement, and mentality. All the zygote needs is a nourishing place to develop namely the mother’s uterus. Within a brief time after conception, the zygote divides into two cells, which then divide into four cells, which then divide into eight cells, and so on. From conception to two weeks is referred to as the preembryonic period, while from week two to the closure of week eight marks the embryonic period. By the end of the embryonic period the embryo will show small but fairly developed organs and begin to take on a more recognizable human form. The commencement of week nine to the moment of birth marks the fetal period. During this time the fetus will show remarkable growth and maturation of organs and appendages. At approximately thirteen weeks, the heart begins to beat, even though the fetus still weighs but a few ounces.
How long does pregnancy last?
Normal pregnancy lasts approximately forty weeks and is typically broken into three equal time periods called trimesters. It is desirable to deliver after at least thirty-seven weeks of pregnancy with the newborn weighing greater than 5.5 pounds or about 2.5 kilograms. Infants born prior to the thirty-seventh week are referred to as premature, while infants born weighing less than 2.5 kilograms are called low birth weight (LBW) infants. Premature and low birth weight infants find life more challenging in the days, weeks, and months that follow as they are at greater risk for medical complications. Premature infants are often introduced into the real world before their organs, especially their lungs, are fully developed and capable of coping with the new environment. This is the price humans pay for having such a large head. Humans must be born before the skull becomes too large to pass through the birth canal. From a developmental standpoint, humans probably should stay in the mother’s womb for a few more weeks.
