Reproduction in Human Beings
Most species have two sexes: male and female. Each sex has its own unique reproductive system. They are different in shape and structure, but both are specifically designed to produce, nourish, and transport either the egg or sperm.
In human beings, reproduction is much the same as for other mammals. Specialized reproduction organs are located in the lower abdomen. The male has glands called testes that make microscopic, tadpole-shaped sperm cells. The female has glands called ovaries that make pinpoint-sized eggs cells. Together they result in a fertilized egg cell and the beginning of a new life.
Male Reproductive System
The male reproductive system, like that of the female, consists of those organs whose function is to produce a new individual, i.e., to accomplish reproduction. This system consists of a pair of testes and a network of excretory ducts, seminal vesicles, the prostate, the bulbourethral glands, and the penis.
The testes lie outside the abdominal cavity of the male within the scrotum. They begin their development in the abdominal cavity but descent into the scrotal sacs during the last 2 months of foetal development. This is required for the production of sperm because internal body temperatures are too high to produce viable sperm.
In the body of an average male, there are two testicles located in a sac called the scrotum. On top of these organs is the epididymis.
The penis has a long shaft and enlarged tip called the glans penis. The penis is the copulatory organ of the males.
A mature sperm, or spermatozoan, has 3 distinct parts: a head, a mid-piece, and a tail. The tail is made up of microtubules that form cilia and flagella, and the mid-piece contains energy-producing mitochondria. The head contains 23 chromosomes within a nucleus. A cap called the acrosome, which is believed to contain enzymes needed to breach the egg for fertilization, covers the tip of the nucleus. A normal human male usually produces several hundred million sperms per day. Sperms are continually produced throughout a male's reproductive life, though production decreases with age.