The reproductive system is a collection of organs that work together for the purpose of producing a new life. Scientists argue that the reproductive system is among the most important systems in the entire body. Without the ability to reproduce, a species dies.
The major organs of the reproductive system include the external genitalia and internal organs, including gonads that produce gamete, which is a cell that fuses with another cell during conception in organisms that reproduce sexually. Substances such as fluids, hormones, and pheromones are also important to the effective functioning of the reproductive system.
The male reproductive system consists of two major parts: the testes, where sperm are produced, and the penis. In humans, both of these organs are outside the abdominal cavity. Having the testes outside the abdomen facilitates temperature regulation of the sperm, which require specific temperatures to survive. If the testicles remain too close to the body, the higher temperature will likely harm the spermatozoa, making conception more difficult or impossible. The testes are carried in an external pouch known as the scrotum, where they normally remain slightly cooler than body temperature to facilitate sperm production.
The two major parts of the female reproductive system are the vagina and uterus — which act as the receptacle for semen — and the ovaries, which produce the female's ova. The vagina is attached to the uterus through the cervix, while the Fallopian tubes connect the uterus to the ovaries. In response to hormonal changes, one ovum, or egg — or more in the case of multiple births — is released and sent down the Fallopian tube during ovulation. If not fertilized, this egg is eliminated as a result of menstruation.