Men's Health - Body maintenance
Male development and hormones
The Journey of Man
Changes in our body occur throughout life. From our time in the womb right through to older age our body is continuously adapting to accommodate the environment and its own individual needs. At certain times in life major alterations occur in which hormones play a crucial part.
The route planner
What started you on the road to becoming a man? Whether a baby develops into a boy or a girl depends on which pair of sex chromosomes get together. Put two X chromosomes together and a girl develops, put and X and a Y-chromosome together and a boy develops.
Very early on in pregnancy, at around 6-8 weeks of pregnancy, the Y chromosome kicks into action and triggers testes to develop - without a Y chromosome this embryonic tissue would have become ovaries. The fetal testis produces the male hormone testosterone and this promotes the development of the penis and scrotum. In doing this, testosterone prevents the formation of fallopian tubes, a womb (uterus), and vagina.
The bumpy road of puberty
In boys the process of sexual development, called puberty, starts between the ages of 12 - 15 years old and lasts for around 3-4 years. During this time hormones secreted by the pituitary gland in the brain, called follicle stimulating hormone (FSH) and luteinising hormone (LH), prompt the testes to produce more testosterone causing a sharp increase in the levels of this male sex hormone.
Testosterone in turn stimulates the physical changes that turn a boy into a man. These changes are known as the secondary sexual characteristics. They include enlargement of the penis, testicles, and scrotum; the appearance of hair under the armpits, around the genitals, on the face, and elsewhere on the body; voice breaking; and growth and muscle development.
Once puberty is reached sperm are continuously manufactured by the testes. Arousal in response to sexual stimulation develops and sexual attraction to other people occurs.
The open highway of adulthood
During the adult years testosterone continues to promote sperm formation in the testes. It also continues to cause hair to appear on the face and body, and ironically is believed to be involved in hair-loss from the head or male-pattern baldness.
Going up or down the hill
With increasing years the level of testosterone in the body gradually declines. In the middle years many men experience tiredness, loss of libido, poor erections, loss of muscle mass, mood swings and irritability. Some believe that these symptoms are a result of lower testosterone hormone levels and that giving men replacement testosterone therapy helps to overcome these symptoms. Others believe these symptoms are more likely to be due to psychological issues than physical ones. Whether the more accurately called 'male andropause' (male hormones being known as androgens) - exists or not continues to be hotly debated in academic circles and as such, the jury is still out.
