The anatomy of the reproductive system includes those organs, tissues, and vessels that participate in the process of reproduction, or the generation of one or more offspring from a male and female parent. Unlike the other systems of the human body, the anatomy of the reproductive system differs significantly in men and women. In women, the main organs include the vagina, uterus, and ovaries, while in men the main organs of reproduction are the penis, the scrotum, and testes. The fallopian tubes and cervix link these organs in the female reproductive system, while in men, the vessels include the epididymis and vas deferens. A discussion of the anatomy of the reproductive system must also include its smallest units, the sperm cell in men and the ovum or egg in women.
In both men and women, the anatomy of the reproductive system can be divided into external and internal organs. The female external organ is often referred to as the vagina. This organ, however, is technically the internal canal that conducts male sperm into the uterus.
External female genitalia include the protective labia majora, the large folds that envelop the remaining external organs: the labia minora, the clitoris, and Bartholin’s glands. The labia minora are the smaller folds that protect the vaginal opening as well as the opening to the urethra, or urinary tract. The clitoris is a small, nerve-filled organ anterior to the vaginal opening that is homologous to the male penis. Women also have Bartholin’s glands, which release secretions that provide initial lubrication for the penis upon entry to the vagina.
External organs of the male reproductive system include the penis, testicles, and scrotum. The penis is the organ that enables the sperm to reach the female egg during intercourse, or vaginal penetration. Dense with blood vessels, it becomes erect during arousal due to a rush of blood flow to the region, enabling it to penetrate the female vagina. Behind the penis is the scrotum, the external sac that contains and protects the paired testicles. These testicles or testes are the organs that produce sperm, the male reproductive cells.
The anatomy of the reproductive system must also include the internal organs of reproduction. In women, these are the vagina, the uterus, and the ovaries. The vagina is the expandable canal, only a few inches deep, that leads to the uterus and through which a baby passes during childbirth. At the back of the vagina is the cervix, an opening through which sperm passes en route to the uterus. The uterus is the space where the fetus grows during pregnancy, and it also can expand a great deal.
On either side of the upper uterus, the fallopian tubes lead to the ovaries, the female sex organs. These organs produce the ova or eggs that are released each month in order to be fertilized by the male sperm. If this does not occur, they are expelled from the body along with the lining of the uterus, where the fertilized egg would imbed itself upon conception, in the form of menstruation.
The internal anatomy of the male reproductive system includes the urethra, vas deferens, and epididymis. Beginning with the opening at the tip of the penis, the urethra is the internal vessel that conducts semen, the sperm-containing fluid, and urine out of the body. It leads to the vas deferens, the tube that brings semen to the urethra.
The epididymis is the storage unit of the testes. It is situated behind each testicle and is a tube that houses the sperm cells produced by the testicles until they are mature enough to be able to fertilize the female egg. During arousal, these cells are released from the epididymis into the vas deferens, where they mix with seminal fluid to form semen, which will be released into the female vagina during ejaculation.