Maternity & Kid's Care

Archive for the ‘Fertilization’ Category

Fertilization or conception occurs when a sperm from the male pierces the cell wall of an ovum or egg from the female. Once the ovum is fertilized, it begins to grow. At first the fertilized ovum which is also called zygote consists of only one cell. After a few hours, the zygote divides into new cells. Each of these two new cells also divides. This kind of multiplication goes on. The entire pre natal period consists of three sub periods. They are period of ovum, the period of embryo and the period of foetus.

The first two weeks from the time of conception, until the zygote is attached within the uterus is the period of ovum. Conception occurs in the fallopian tubes and the zygote travels down to the uterus. It starts dividing and multiplying in the beginning of this period. by the time it reaches the uterus, it is about the size of a pin head. It develops very small tendrils and with the help of these tendrils, the ovum will attach itself to the uterine wall. The specific process of attachment of the ovum to the uterine wall is called implantation. Implantation occurs approximately around ten days after fertilization.

The period of embryo begins from the zygotes attachment to the uterine wall. This period usually lasts from two weeks after fertilization to the eighth week. By the end of the period of ovum, the egg has two distinct parts, one inner cell mass and the outer layer called trophoblast. The inner called mass differentiates into three clear layers. Of the three layers the outer layer is ectoderm from which develop the outer layer of skin, the hair, the nails, parts of teeth, skin, glands, sensory cells and nervous system. The middle layer is called mesoderm from which develop inner skin layer, the muscles, skeleton and the circulatory and excretory organs.

The inner layer is called endoderm from which will develop the lining of the entire gastro intestine tract, the trachea, bronchia, lungs, liver, pancreas, salivary glands, thyroid glands and thymus. The outer layer will develop into accessory tissues, which protect and nourish the embryo.

As the embryo grows, additional life supporting structure continues to develop. Among these, the umbilical cord and placenta which maintain the connections with the mother’s body through which the embryo gets nutrients and expels waste. Placenta is a membranous organ into which mother’s blood stream and foetus blood stream end. Nutrients from the mother’s blood pass to the foetus through placenta. Amniotic sac acts as a buffer to protect the embryo from shocks experienced by the mother.