the fertilized ovum divides at the zygote after fusion.
when does the fertilized ovum divide after fusion?
the zygote
the human reproductive system usually involves internal fertilization by sexual intercourse. in this process, the male inserts his penis into the female's vagina and ejaculates semen, which contains sperm. a small proportion of the sperm pass through the cervix into the uterus, and then into the fallopian tubes for fertilization of the ovum. only one sperm is required to fertilize the ovum. upon successful fertilization, the fertilized ovum, or zygote, travels out of the fallopian tube and into the uterus, where it implants in the uterine wall. this marks the beginning of gestation, better known as pregnancy, which continues for around nine months as the foetus develops. when the foetus has developed to a certain point, pregnancy is concluded with childbirth, involving labor. during labor, the muscles of the uterus contract and the cervix dilates over the course of hours, and the baby passes out of the vagina. human infants are nearly helpless and require high levels of parental care. infants rely on their caregivers for comfort, cleanliness, and food. food may be provided by breastfeeding or formula feeding.
human reproductive system
the reproductive function of the uterus is to accept a fertilized ovum which passes through the utero-tubal junction from the fallopian tube. the fertilized ovum divides to become a blastocyst, which implants into the endometrium, and derives nourishment from blood vessels which develop exclusively for this purpose. the fertilized ovum becomes an embryo, attaches to a wall of the uterus, creates a placenta, and develops into a fetus (gestates) until childbirth. due to anatomical barriers such as the pelvis, the uterus is pushed partially into the abdomen due to its expansion during pregnancy. even during pregnancy the mass of a human uterus amounts to only about a kilogram (2.2 pounds).
uterus