Hello frnds, I have written a short summary on foetal birth . Pls check for any mistake.
The journey of life starts with a single cell which enters into birth canal by the process of insemination. Then it goes further into cervix > uterus > isthmus > ampulla and finally reaches to the ovum. The cell is named as “Sperm” which is also the smallest cell our body. Sperm’s body is divided into four parts - 1} Head 2} Neck 3} Middle piece
4} Tail. Its head contains acrosome whose constituents are some enzymes like Zonalysin or acrosin . Its neck contains centrioles and middle piece contains spirally coiled mitochondria which functions as its power house. The tail just helps in locomotion till reaching upto ovum. The movements of cilia also helps the sperms to reach the ovum. As the sperms reaches to the ovum , out of many sperms , only a single sperm fuses with the egg. As the sperm reaches the corona radiata it moves further towards the zona pellucida and releases enzymes which dissolves the layer and the nucleus of the sperm fuses with the nuclei of egg to form a diploid zygote. Then zygote further starts division to become a blastocyst . Then blastocyst moves further into the uterus and gets implanted by the process of implantation. As the blastocyst gets implanted to the endometrial lining of uterus it starts growing further and gets transformed into an embryo > foetus. The foetus is connected to the parent body via placenta. The placenta performs many functions such as transport of nuritents, exchange of gases, removal of excretory waste etc. At the end of one month, Heart of foetus is formed. Further at the end of first trimester limbs and digits are easily seen. After five months the foetus body is covered with hairs, eye lid and eye lashes gets separated ,foetus starts kicking and all the vital organs is fully developed. By the end of nine months the foetus is ready for the delivery. The process of delivery of the foetus is called as Parturition which is controlled by a neuro endocrine mechanism. Its signals are generated from the fully developed foetus and placenta. The hormone which is responsible for the process of Parturition is Oxytocin. Oxytocin causes stronger uterine contractions which helps the foetus to come out.