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Fetal development Fetal Development Fertilization Fetal development starts with the process of fertilization. It starts when the female ovulates producing an egg. This egg then travels into the fallopian tube where it waits to be fertilized. Once sperm enter the body they must travel up the uterus until they make their way up to the egg.
Once at the egg the sperm try to get in. They sperm wiggle their tails until they make it in. Once it makes it in the egg will not any other sperm in. The sperm that made it then drops its tail. After about twenty hours inside the egg the sperm finds the nucleus of the egg and fuses with it.
Now the egg has all the genetic material that it needs to make a new human being. It now's begins to move down into the uterus. The egg is now called a blastocyst. The time that this takes is often measured after the last menstrual period (LMP). The time is also measured in trimesters, three month intervals. After about thirty hours the cell divides for the first time.
It is continuously moving towards the uterus where it will call home for the next nine months. After about two days it has divided to having about eight cells. After four days it is in the uterus and has to land somewhere and attach itself to the endometrium. The eighth day is when implantation occurs.
The fertilized egg then implants itself on the endometrium, the uterine lining, and begins to grow. The cell begins to grow and develop. By the 12 th day the blastocyst has approximately two thousand cells in it. It has had time to attach itself to the endometrium and these anchors are called protuberances.
Embryonic Development After about three weeks the tiny little heart is developed enough to start beating and has the ability to pump blood. At this time the blastocyst's becomes an embryo. There are three layers that form the embryo. These layers are called the germ or cell layers. The outer cell layer will eventually become the backbone, the brain, and the nerves. This layer also makes the skin, the hair, and sebaceous and sweat glands.
The middle layer is going to be the lower layer of skin, the bones, and the muscles. Blood and lymph vessels are also made from this layer. Blood cells and the heart muscles make a primitive bloodstream (Nilsson, 1990, p. 77). The sex organs and the kidneys also come from this layer. The inner layer makes up the a simple intestinal tube with a mucus membrane.
From that tube the lungs and urinary tract form. Everything from all the layers then come together to form the organ system. Then the embryo can do a test run with the system. This happens every day while the organs are being formed. At around four weeks from the LMP the embryo begins to form a backbone. The bones are split in two, half on each side.
The nerves begin to form down the middle of the bone pieces. The placenta is by now drawing nutrients from the mother. The nutrients then go down the umbilical cord into the embryo. The wastes then go into the mother where they are discarded. After about five weeks from the LMP the embryo is visible to the world outside. The doctors can look at the embryo and measure it.
The length is called the crown-rump length. The sixth week is when the measurements are normally taken. Everything is continually growing and the whole body straightens up. The head makes up about one-third of the embryos body. There is still no skull so you can see the brain.
The arms as well as the legs are very short. This is because the embryo grows from the head down to the toes. That means the head is going to be huge compared to the rest of the body. After six weeks from the LMP the embryos backbone has come together and there are two arteries that run down each side of it. The skin on the embryo is very thin and translucent. The placenta and the embryo are connected by the umbilical cord.
The one large artery and two smaller veins run through the umbilical cord. Everything that the embryo needs will come through the umbilical cord. Fetal Development After about eight weeks from the LMP the tiny little embryo has every organ that it needs. The embryo is now referred to as a fetus.
The risks of miscarriages and malformations has greatly been reduced. The brain is visible from the outside of the fetus. It still isnt controlling the fetus because it has not been fully developed yet. By the third month the organ and organ systems are becoming interconnected. The brain is starting to take over the functions of the organs. The yolk sac is forming the blood cells.
At the fourth month the fetus is over ten centimeters long. It only weighs about twenty grams though. The face is starting to form and look more human. The five outgrowths that make up the face are moving into position. One of them make up the nostrils and nose and the middle of the upper lip.
Two of the other outgrowths come from up under each eye and form the cheeks and the rest of the upper lip. The other two formed the lower lip and the chin. The eye forms when the forebrain issues a hollow stalk on both sides of the brain. The stalks start to thicken on the end and this becomes the eyeball. The iris grows from the edges in. Then the skin grows over the eye and this becomes the eyelid.
The ear grows from three different parts. From the skin a hollow area forms and this will be the inner ear. A little after that the outer ear develops and the middle ear then forms. Around the end of the fourth month the fetus can hear sounds that come from the mother and the outside world. The arm and the foot are formed by from little buds that stick out from the body. These little buds keep growing to form the arms and legs.
At the end of the buds there are little flipper like formations that will be the hands and feet. The arms will get longer before the legs will. After about the third month the hands can grab things and the feet can kick. The kicks are usually to small for the mother to fell them though.
The bones form from cartilage which is what is initially formed in the fetus while it is still in the uterus. The skull bones are flexible and they can be damaged during labor. Sometimes collarbones and arm bones can be broken and this really doesnt cause much concern because they just heal themselves. The bones usually heal without scars or any traces of breakage. During the third month after the LMP little hairs appear on the fetus. The fetish body starts growing a fine hair called lanugo (from the Latin lana for fine wool) (Vaughn, 1996, p. 133).
During the first few months of development you cannot tell apart the male from the female by looking at them. A small bud forms between the legs which will form the male penis or the female clitoris. A swelling forms on either side of the bump which will be the scrotum in boys. In girls a slit will form and this will become the vagina. The testicles form deep inside the abdomen. The male can produce sperm right up to an old age.
The ovaries already have all the eggs that the women will ever need in her life. Approximately half way through the pregnancy the mother can start to feel the fetus kicking inside of her. Then after a couple more weeks the fetus has grown to little over a pound. The fetus can see some light as it comes through the abdominal wall. The fetus may frequently suck its thumb (Silverstein, Silverstein, and Silverstein, 1994, p. 49). During the seventh month after the LMP the fetus starts to put on weight.
The weight of the fetus increases by nearly half a pound a week. the mother has to watch her weight because overeating during pregnancy can be bad for the fetus. If the mother doesnt eat enough the fetus can be starving for food and that can impact the brain of the fetus and cause malformations. Smoking or drinking during pregnancy can form defects in the fetus and cause it to be deformed. The fetus is growing in size and has been training for his entrance into the real world. He has been moving around for quite awhile, since about the eighth week.
When the fetus moves inside the uterus he is not just playing he is helping to build muscle and strengthen his bones at the same time. At this time the fetus is also starting to run out of room in the uterus. Now the fetus cant do somersaults like it used to earlier in development. Sometimes the fetus can get hiccups, the mother feels these as small jerks.
During the eighth month after the LMP the fetus has double his weight and now weighs about five and a half pounds. The brain and central nervous system has developed far enough that if the fetus was to be born now he would have a good chance of surviving. The fetus is often checked by a doctor to see if he is in the right position, head down. The ninth month after the LMP is when the fetus puts on a lot of weight. The majority of fetal weight gain occurs in the third trimester (Golfers Encyclopedia Inc. , 1997, CD-ROM). Most of the lanugo has disappeared by now and is swallowed by the fetus.
This collects at the bottom of the bowel. It forms a greenish-black ooze called me conium. The baby will pass this through as his first bowel movement. The Pregnant Body During the first trimester the mother can and will experience vomiting and nausea, also called morning sickness. These symptoms usually occur after about eight weeks after the LMP. The mother will experience increased urination due to the pressure on the bladder.
Breast soreness or tingling often occurs do to the hormonal stimulation (Software Tool works Multimedia Encyclopedia, 1992, CD-ROM). Fatigue is also common. During the second trimester the mother will most likely experience constipation. Sometimes the uterus will contract may occur.
They are called Braxton-Hicks contractions. She may also feel lightheaded and faint. This is caused by the diversion of blood to the uterus, placenta, and fetus. The mother may also experience heartburn because the fetus is growing in size which causes pressure to be placed on the stomach. This stage is more comfortable than the first. The third trimester become more uncomfortable than the first two.
The mother may get hemorrhoids, headaches, swelling of the legs, and varicose veins may occur. The lungs cannot take in enough oxygen so the mother may feel short of breath. Near the end of the fetal developmental stage she may experience pelvic discomfort because the fetus is settling into the position that he will be born by, head down near the pelvis. Insomnia may also be an occurrence days prior to the delivery.
The mother may feel false labor pains which can be uncomfortable. Labor There are three signs that can warn the mother that labor is beginning, there are regular contractions, the membrane ruptures (water breaking), and mucus mixed with blood. During the last month of pregnancy there are usually contractions that dont mean much. When the contractions are less then about ten minutes apart then that is a sure sign that labor has begun. Sometimes labor will begin with the amniotic fluid flowing out of the vagina. This means the amniotic sac around the fetus has ruptured and the mother should get to the hospital immediately.
The uterus was contracting, or squeezing, to push you out into the world (Cole, 1984, p. 30). Once the mother is at the hospital she will find it a nice place to be. The hospital equipment has changed over the years and the mother should be quite comfortable. Most of the time the mother will have someone with her, such as a mother or her husband.
Labor most likely happens in three stages. First the dilatation stage begins. This starts when the contractions begin or the water breaks. During this stage the cervix, or the opening at the bottom of the uterus, is expanding and opening to a larger size. When the cervix is fully dilated it is about four inches across. While all this is happening the fetish head is settling into the birthing position.
This stage of labor is the longest and can take anywhere from six to twenty hours. If the mother has given birth before the time will be less. The second stage of labor is called the expulsion stage. This stage lasts from the time that the cervix is fully dilated until the baby is born. This is the stage where the mother has to push the fetus out of the uterus. This stage of labor normally takes from just about a few minutes to a little over an hour.
The last stage of the delivery is called the delivery of the placenta. It begins right after the baby is born until the entire placenta is expelled from the uterus. This stage normally takes about fifteen minutes to complete. But it could take up to an hour. This stage is usually the easiest of the three.
The fetus has a lot of stress being put on him when he is being born. During the contractions the fetus has a small lack of oxygen due too the pressure being put on the placenta and the umbilical cord. During the contractions the fetish heart rate slows down but regains its strength in between the contractions. This phase of labor is very punishing on the fetus and the adrenal glands start producing massive amounts of adrenaline and noradrenaline. The adrenaline is important because it helps to keep the heart going if the oxygen supply is cut off.
It keeps the blood flowing to the sensitive brain and raises blood-sugar levels. The adrenaline also helps to clear the lungs of the liquid that has been in their since the beginning of the fetish life. It also helps to prepare the lung for breathing in the outside air. Once out of the mother the babies umbilical cord is cut and the baby is on his own.
The mother may experience great pain during this phase of the pregnancy. To help her relax the husband will usually give her a massage. Just having the father there will make the mother be more comfortable. If she feels the need for pain relievers there are several kinds. She could be given pethidine but that would affect the baby.
Another option is inhaling a mixture of nitrous oxide and oxygen. She could also be given a local anesthetic to the nerves of the cervix to relieve the pain. But the most common type of pain relief is the epidural anesthetic. It numbs the nerves right as the come out of the spinal cord. After Birth After the baby is born he is checked by a nurse, measured, and weighed. Then he is wrapped in a blanket and given to the mother.
The baby is then moves towards the mothers breast by instinct. This helps to teach the baby how to suck. The baby will feed up to ten times a day. The mothers breasts may become swollen and tender due to the production of milk.
The mothers milk is loaded with nutrients and minerals that is essential to the development of the baby. It is recommended that the child be breast-feed for at least 3 months and if at all possible longer.
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