Question

sexual hormones regulate secondary sexual characteristic

Answer 1

Male and female gonads are regulated by FSH and LH from the pituitary; their production is stimulated by GnRH, secreted by the hypothalamus.

While primary sex characteristics are those that are present at birth, secondary sex characteristics are those that appear during puberty. These secondary sex characteristics are caused by hormones released at the time of puberty, which usually is around two years earlier in girls than in boys. While both boys and girls grow taller in their teenage years, the male body becomes more muscular, and the shoulders grow broader than the hips, while the female's hips become wider than her shoulders, and breasts develop.

Some of the first changes in a boy are the growth of his testicles and growth of pubic hair. Later, the chest becomes larger, hair grows in the armpits, muscles grow in the arms and legs and shoulders become larger and stronger. In some males, hair also grows on the chest, but generally, Asian men are less hairy and less muscular than Caucasian men, and those from Africa have coarser body hair. Facial hair, which usually grows first above the lips and later grows on the cheeks, may grow into a mustache and beard unless the boy shaves regularly. The larynx (voice box) becomes larger as well, resulting in a deeper voice.

Answer 2

LH stimulates production of the sex hormones (androgens) by the Leydig cells of the testes. It is also called interstitial-cell-stimulating hormone. The most widely-known androgen in males is testosterone, which promotes the production of sperm and masculine characteristics.