Vital Roles in Reproduction and Male Physical Development

Testes OverviewThe testes are the part of the male reproductive system that secrete testosterone, the hormone responsible for physical changes in maturing adolescent males. In adulthood, testosterone plays an essential role in bone density, muscular strength and libido. Reduced production of this important hormone is usually the result of disorders in the testicles.


The testes are shaped like large grapes and located behind the penis. A loose skin called the scrotum encloses both organs and provides temperature control. However, the absence of bone or muscle to shield the testes makes them vulnerable to injury.

Essential Functions

The testicles are referred to as the male gonads (ovaries in females). These organs produce sperm and ensure the overall well being of the male reproductive system. In addition to their role in reproduction, they are also part of the endocrine  system in producing and secreting the male sex hormone testosterone. Male physical development during puberty is attributed to this hormone.

The Testicular Hormones

The production of testosterone in the testes plays a crucial role in the physical transformation of males during adolescence. Testosterone stimulates masculine development during puberty and maintains a proper hormone balance in the body during adulthood.
The pituitary gland and the hypothalamus control the amount of testosterone produced and secreted by the testes. It is the hypothalamus that sends signals to the pituitary gland if the body needs more of the hormone. If too much is being produced, the hypothalamus alerts the pituitary gland to lessen production and secretion.

During the adolescent stage, testosterone is responsible for the following:
1. Development of the Adam’s Apple
2. Lowering of voice
3. Development of sex organs
4. Height increase
5. Muscular mass increase
6. Facial and body hair growth

During adulthood, testosterone still plays essential functions including:
1. Libido maintenance
2. Muscle mass and strength maintenance
3. Healthy bone density promotion
4. Sperm production

Hypogonadism: A Common Testicular Disorder

This specific disorder is caused by the decreased production and secretion of testosterone. A decrease in testosterone levels causes several problems in males including low sex drive, reduced muscle mass, and low sperm count. It is also associated with the loss of body hair.
Hypogonadism is categorized into two types: primary and secondary. It is referred to as “primary” when the defect is with the testicles and “secondary” when the cause of the defect involves the pituitary gland and its function in hormone production. The causes of the disorder are many. Aging is the most common cause, but certain medications or testicular injury may be the culprit. Other circumstances, like exposure to radiation and chemotherapy, may also cause testosterone levels to drop. In addition, defects in the hypothalamus and the pituitary gland hinder the reproduction and secretion of the hormone.


The testes are vital not only as part of the endocrine system, but also in the male reproductive system as well. The production of sperm and testosterone are essential to reproduction and the development of physical masculinity.