________________
Human Body
function of the ovaries awakens and they begin to secrete their own hormones, estrogens.
The Testes
Testes are the chief male gonads like the ovaries in the female, having two major functions: they produce the germ cells that act in reproduction and they also are powerful endocrine organs secreting male sex hormones. The testes in the adult are small ovoid structures about 3 to 5 cms. long, 2-3 cms. wide and weighs 20.30 gms. suspended in the scrotum.
109
The male sex hormones are called androgens and testosterone is the major androgen produced by the testes. Other androgens are produced by testes as well as adrenal glands but all of them are slight in comparison with testosterone. The function of the testes is controlled by the hypothalamic-pituitary system, and its regulation by the gonadotrophic hormones is accomplished according to the feedback principle. As in the case of female, pituitary hormones play a profound role in controlling the functions of the testes in male. At least some differences in the typical behaviour and personality between men and women seem to be linked with the secretion of testosterone.
The secretion of testosterone begins in the male foetus. Small quantities of testosterone continue to be secreted during childhood, but there is a dramatic increase at puberty. This sparks a furious growth-spurt along with the development of the mature sexual organ.
Testosterone is responsible, to some degree, for sexual interest and sex drive, but an intricate complex of psychological factors is superimposed on this underlying endocrine mechanism.
Hormone and the Life Cycle
The growth and changes in the body are largely under hormonal control. So also is the variation that repeats its cycle regularly everyday the so-called 'circadian rhythms' to wake during the day and sleep at night.
Several hormones are active before birth e.g. those controlling metabolism. Growth hormone and thyroxine are
Jain Education International
For Private & Personal Use Only
www.jainelibrary.org
