Fuktningssyklus

Fuktningssyklus, or fertilization cycle, is the biological sequence that leads to the combination of genetic material from two gametes and, in many species, the establishment of pregnancy. The term is commonly used in human biology and veterinary contexts, and it encompasses the formation of gametes, the release and pickup of the female gamete, the chance of fertilization, and the early stages of embryo development up to implantation.

In humans, male gametes (sperm) are produced by spermatogenesis in the testes and are delivered to the female reproductive tract during intercourse. Female gametes (ova) are released during ovulation from the ovaries and are typically viable for about 12–24 hours. Fertilization occurs when a sperm penetrates the oocyte, usually in the fallopian tube, forming a zygote. The zygote begins dividing as it moves toward the uterus.

Implantation into the uterine lining typically occurs about 6–10 days after fertilization, leading to pregnancy. Hormonal regulation involves GnRH, FSH, LH, estrogen, and progesterone, with the luteal phase supporting the uterine environment. If fertilization does occur, the developing embryo signals maintenance of the corpus luteum through human chorionic gonadotropin (hCG). If not, hormone levels fall and menstruation begins.

Variability is common: cycle length, timing of ovulation, and the fertilization window differ among individuals and species. Clinically, the fertilization cycle is central to understanding infertility, conception timing, and pregnancy outcomes. Assisted reproductive technologies, such as in vitro fertilization, directly manipulate stages of the cycle, while contraception aims to prevent fertilization or implantation.