The physical changes during puberty are due to <u>secondary sex characteristics</u>
Explanation:
Origin: Secondary sex characteristics in male typically originate at the onset and develop during puberty from 9-16 years.
Mechanism: The hypothalamus of the brain initiates the release of follicular stimulating and leutinizing hormones which trigger the Sertoli cells of the testes to begin spermatogenesis and the interstitial cells of Leydig to produce the male sex hormone testosterone.
It is this release of testosterone that leads to the development of secondary sexual characteristics like:
Muscular and strong body
Deepening of voice
Growth of facial, axillary (underarm) and pubic hair
Enlargement of reproductive organs like the scrotum, testes, etc; along with penis lengthening
Spermatogenesis begins along with feelings of sexual drive during this adolescent period
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