Development of the Systems.
As a human being is growing and developing before birth, the systems, organs, and tissues develop and grow in a sequence which is common to all of us. At the time of conception, the physical characteristics of a person are for the more part set. The blueprints for the body's developent are in the genetic material of the sperm and egg. Not only are a person's physical traits initiated at conception, but his spiritual nature is also present.
By the time a child has been developing for only eight weeks in the mothers womb, all the organs are fromed and the external features are established. By the end of twelve weeks, when the child is three inches long, every detail of basic structure is developed. The child will continue to grow in the safety and nourishment of the mother's womb for about thirty more weeks. This thirsty-eight-to forty-week period of development before birth is referred to as gestation. The child is protected during gestation by a sac of fluid called the amniotic sac.
All the materials needed for this miraculous growth period are provided from the mother by means of a sac of blood vessels called the placenta. The placenta attaches to the developing child by means of three vessels which make up the umbilical cord. Blood containing nutrients and oxygen is carried to the child by the two vessels, and carbon dioxide and some wastes are carried back to the mother's system through the third vessel. The blood systems of the mother and the child meet at the placenta, but the blood of the mother and the child never mixes.
The nervous system develops from the neural plate which appears during the third week of development. About six weeks after conception, the child's brain is sending out impluses which control body functions, and the nervous system is controlling the child's movements. At seven weeks the unborn child responds to touch. At twelve weeks, the brain is fully formed, and of course it continues to grow as the child grows. It is unmistakably evident that the tiny growing fetus responds to its environment and knows when it is injured. If injured, the small child exhibits an awareness of intense pain.
As early as the third week, the digestive tube is present. From this tube, all the organs of the digestive system are formed. At six weeks, the stomach begins its lifelong production of digestive juices.
The circulatory system begins to form early in the child's development. At seventeen days, blood cells are present in this tiny child. By the third week, the heart has begun its lifelong rhythmic beating. At four weeks, an intricate network of blood vessels is well developed. By the eight week, the child has a tiny replica of an adult heart.
The lungs, trachea, and bronchial tubes begin to form during the fourth week of devolopment. They are not used until the child takes his first breath outside the mothers womb.
By the fifth wekk, the skeleton of the hcild is taking shape. At first, the bones are made of rubbery cartilage, Ossification, or the replacement of cartilage with bone, begins at the eight week of development and continues until about age 25 when the breastbone ossifies.
At ten weeks of development, the kidneys are fully functioning. Even as early as six weeks they filter uric from blood. By this time, the child begins to move his voluntary about within his protected sac.
And there you go!
After reading this, I just can't figure out for the life of me, why someone would want to have an abortion..........................
2007-02-12 07:58:28
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answer #1
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answered by Andrew90 2
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gills develop and disappear again! some rest from evolutionary history!!
2007-02-12 07:17:25
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answer #2
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answered by Johannes 2
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