Sex Hormones - Puberty

Sex hormones are responsible for some of the most dramatic changes that occur in the body. They control puberty, egg and sperm production, pregnancy, birth and lactation (breastfeeding).

Puberty

Girls

In girls, between the ages of about 10 and14, the pituitary gland produces Luteinising Hormone (LH) and Follicle Stimulating Hormone (FSH) which together stimulate the production of the sex hormones by the ovaries.

The ovaries start to produce oestrogen and progesterone which begin the bodily changes that happen during puberty. The changes, known as secondary sexual characteristics, are:
  • The breasts develop
  • The hips and thighs widen
  • Pubic and underarm hair develop
  • The ovaries start to produce eggs
  • Menstruation starts
A female child and a mature woman stand side by side showing the development of female sexual characteristics. Mature breasts, broader hips and pubic hair are highlighted

Boys

In boys, between the ages of about 12 and 15, the pituitary gland produces LH and FSH, which together stimulate the production of the sex hormones.

The testes start to produce testosterone which begins the development of secondary sexual characteristics. In boys these are:
  • The voice breaks
  • Hair grows on the face and the body
  • The body becomes more muscular
  • The genitals develop
  • Sperm are produced
A male child and a mature man stand side by side showing the development of male sexual characteristics. Facial hair, broad shoulders, increased body hair, pubic hair, mature genital organs and a more muscular body are highlighted

Question 2

a)
Which endocrine gland starts off the process of puberty?
b)
Which two hormones, produced by this gland, stimulate the production of sex hormones?
c)
What hormone is produced in the testes?
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