During puberty reproductive hormones cause secondary sex characteristics…

The idea

Puberty is the stage when the reproductive system becomes functional. The pituitary gland releases hormones that stimulate the testes to produce testosterone and the ovaries to produce oestrogen. These reproductive hormones travel in the blood and trigger secondary sex characteristics. In males, testosterone causes deepening of the voice, growth of facial and body hair, and increased muscle mass. In females, oestrogen causes breast development, widening of the hips, and growth of pubic hair. These changes prepare the body for reproduction. Understanding this helps explain how the body coordinates growth and development during adolescence.

What earns the marks

• Puberty is triggered by hormones from the pituitary gland, which stimulate the gonads (testes and ovaries).
• Testosterone is the main male reproductive hormone produced by the testes; it causes secondary sex characteristics such as voice deepening and facial hair growth.
• Oestrogen is the main female reproductive hormone produced by the ovaries; it causes secondary sex characteristics such as breast development and hip widening.
• Secondary sex characteristics are physical features that develop during puberty but are not directly involved in reproduction, unlike primary sex characteristics.
• The hormones travel in the bloodstream to target organs, where they bring about specific developmental changes.

Common mistakes and how to put them right

• Confusing primary and secondary sex characteristics.

  Put it right: Primary sex characteristics are the reproductive organs present at birth; secondary sex characteristics develop during puberty.

• Thinking that only females have oestrogen or only males have testosterone.

  Put it right: Both hormones are present in both sexes, but in different concentrations.

• Believing that puberty is controlled by the reproductive organs alone.

  Put it right: The pituitary gland in the brain releases hormones that stimulate the testes and ovaries to produce their hormones.

Exam tips

• Learn at least two secondary sex characteristics for each sex and link each to the correct hormone.
• Use the terms 'testosterone' and 'oestrogen' accurately, and state the organ that produces each.
• When describing the role of the pituitary gland, mention that it stimulates the gonads to release reproductive hormones.