fertilization is the process of egg and sperm fuse. in humans, occrus processes in the body, so-called internal fertilization. fertilizations began the process of intercourse,about 350 million sperm are dispersed into the vagina. but few sprems Graduates toreach the egg surface. some sperm trying to penetrate the egg cell protective layerconsisting of corona radiata, the zone pellucida and plasma membrane. basically, onlyone sperm that can penetrate the protective layer of the egg cell and the ovum. at thesame timr penetration of sperm, egg secret specific chemical compound, which isnecessary to block other sperm from penetrating the egg. later, conyinues egg cell to divide by meiosis II to produce haploid gametes. completedwhen fertilization spermnucleus (haploid) fuse with the egg cell nucleus (haploid) and create a zygote (diploid).Next, the zygote divides by mitosis in the oviduct, and occrus repeatedly on the way to the uterus. more or less than a week after fertilization, the zygote has developed intoone ball called a blastocyst cavity structure. then moves toward the uterus the blastocyst and implanted in the uterine wall. This process is called implantation.
