After having been deposited in the far end of the vagina at ejaculation, millions of sperm cells travel through the uterus towards the fallopian tubes. Only a few hundred of them manage to reach the ovum. The penetration of one of the sperm cells into the ovum, or fertilization, results in the merging of their respective cellular nuclei. The fertilized ovum, called the zygote, descends through the fallopian tube towards the uterus. It divides progressively into a number of cells in order to form an embryo, or blastocyst, which implants itself in the endometrium (nidation). | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / QA International |
Bildgröße: | 1970 px × 2400 px |
Modell-Rechte: | nicht erforderlich |
Eigentums-Rechte: | nicht erforderlich |
Restrictions: | - |