Conditions Responsible for Puberty Changes
Role of the Pituitary Gland
The pituitary gland produces two hormones: the growth hormone, which is influential in determining the individual's size, and the gonadotropic hormone, which stimulates the gonads to increased activity. Just before puberty, there is a gradual increase in the amount of the gonadotropic hormone and an increased sensitivity of the gonads to this hormone; this initiates puberty changes.
Role of the Gonads
With the growth and development of the gonads, the sex organs - the primary sex characteristics - increase in size and become functionally mature, and the secondary sex characteristics, such as pubic hair develop.
Interaction of the Pituitary Gland and the Gonads
The hormones produced by the gonads, which have been stimulated by the gonadotropic hormone produced by the pituitary gland, act in turn on this gland and cause a gradual reduction in the amount of growth hormone produced, thus stopping the growth process. The interaction between the gonadotropic hormone and the gonads continues throughout the individual's reproductive life, gradually decreasing as women approach the menopause and men approach the climacteric.
Body changes in puberty
1. Changes in body size - in terms of height and weight. The greatest increase in height comes in the year following the onset of puberty. After that growth declines and continue at a slow rate. Weight gain comes from increase in fat, bone and muscle tissues.
2. Changes in body proportions - the thin long trunk of the older child begins to broaden at the hips and shoulders and waistline develops.
3. Primary sex characteristic in the growth and development of the sex organs - the gonads or testes and that of the penis in male. For girls it is the first menstrual flow. This is the discharge of blood, mucus and broken down cell tissues from the uterus that will occur every twenty - eight days.
4. Secondary sex characteristics.