Explain the roles of FSH and LH in spermatogenesis in the human male.

IB DP Biology Higher Level (2023 syllabus) — D3.1 Reproduction · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

FSH binds to receptors on Sertoli cells in the seminiferous tubules, stimulating them to nourish and support developing sperm cells (spermatocytes and spermatids) and to promote their maturation.
LH binds to receptors on Leydig cells in the interstitial tissue, stimulating these cells to secrete testosterone.
Testosterone acts locally on Sertoli cells and the seminiferous tubules, where it is required for the completion of spermatogenesis, particularly the meiotic divisions of spermatocytes.

Examiner tips

Use the exact terms FSH, LH, Sertoli cells, Leydig cells, testosterone, spermatogenesis. Show the sequence: FSH→Sertoli cells→spermatogenesis; LH→Leydig cells→testosterone→Spermatogenesis. Keep the answer concise and directly linked to the mark scheme points.

Common mistakes

Confusing the roles of FSH and LH or omitting the Leydig cell–testosterone link. Using vague language such as "helps sperm" instead of specifying Sertoli or Leydig cells. Failing to mention that testosterone acts locally on Sertoli cells to complete spermatogenesis.

Mark scheme (4 marks)

FSH stimulates Sertoli cells (in the seminiferous tubules)
Sertoli cells nourish / support developing sperm cells (spermatocytes / spermatids) and promote their maturation
LH stimulates Leydig cells (interstitial cells) to secrete testosterone
Testosterone (acting locally on Sertoli cells / seminiferous tubules) stimulates / is required for the completion of spermatogenesis / the meiotic divisions of spermatocytes

Key terms in this question

FSH · LH · spermatogenesis