FERTILIZATION AND PREGNANCY .
She is going to have a baby. Hope a handsome son or a pretty girl.
God may keep and bless the couple.
In human, fertilization of the ovum by the sperm usually occurs in the midpoint of the uterine tube. Penetration of the ovum by the sperm and the initiation of the cell division, which begin at once, may be brought about by lysosomal enzymes in the acrosome [head] of the sperm. Only one sperm penetrate the ovum, because once the ovum has been fertilized a barrier forms around it that normally prevents other sperms from entering.
The developing embryo, now called a blastocyst, moves down the tube into the uterus. Once in contact with the endometrium [of uterus], the blastocyst becomes surrounded by the outer layer of syncytio-trophoblast, which it erodes the endometrium, and the blastocyst burrows in to it [implantation].The implantation side is usually on the dorsal wall of the uterus. A placenta then develops and the trophoblast remains associated with it.
As pregnancy advances the products of conception increase in size and eventually occupy the whole of the uterus cavity, the growing embryo [foetus] attached by its umbilical cord to the placenta is bathed by amniotic fluid which is contained within the “bag of membranes” consisting of the amnion. The function of the amniotic fluid is to provide space for embryo growth and movements and to distribute the pressure due to uterine contractions evenly over the embryo.
Endocrine change:
In women , the corpus luteum in the ovary at time of fertilization fails to regress and instead enlarges in response to stimulation by gonadotropic hormones secreted by the placenta. The placental gonadotropin in humans called human chorionic gonadotropin [hCG].The enlarged corpus luteum of pregnancy secretes estrogens and progesterone. There are degenerative changes in corpus after the fifth month, but it persists through out pregnancy; hCG secretion decreases after an initial marked rise, but estrogen and progesterone secretion increases until just before parturition.
5. INFERTILITY IN THE FEMALE.
In human, fertilization of the ovum by the sperm usually occurs in the midpoint of the uterine tube. Penetration of the ovum by the sperm and the initiation of the cell division, which begin at once, may be brought about by lysosomal enzymes in the acrosome [head] of the sperm. Only one sperm penetrate the ovum, because once the ovum has been fertilized a barrier forms around it that normally prevents other sperms from entering.
The developing embryo, now called a blastocyst, moves down the tube into the uterus. Once in contact with the endometrium [of uterus], the blastocyst becomes surrounded by the outer layer of syncytio-trophoblast, which it erodes the endometrium, and the blastocyst burrows in to it [implantation].The implantation side is usually on the dorsal wall of the uterus. A placenta then develops and the trophoblast remains associated with it.
As pregnancy advances the products of conception increase in size and eventually occupy the whole of the uterus cavity, the growing embryo [foetus] attached by its umbilical cord to the placenta is bathed by amniotic fluid which is contained within the “bag of membranes” consisting of the amnion. The function of the amniotic fluid is to provide space for embryo growth and movements and to distribute the pressure due to uterine contractions evenly over the embryo.
Endocrine change:
In women , the corpus luteum in the ovary at time of fertilization fails to regress and instead enlarges in response to stimulation by gonadotropic hormones secreted by the placenta. The placental gonadotropin in humans called human chorionic gonadotropin [hCG].The enlarged corpus luteum of pregnancy secretes estrogens and progesterone. There are degenerative changes in corpus after the fifth month, but it persists through out pregnancy; hCG secretion decreases after an initial marked rise, but estrogen and progesterone secretion increases until just before parturition.
5. INFERTILITY IN THE FEMALE.
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