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D3.1.13 (HL)—Puberty control

Puberty is initiated by increased GnRH from the hypothalamus, which promotes LH release and increased sex hormone production by gonads.

Syllabus
First assessment 2025
Objective
D3.1.13
Level
HL

Exam analysis

Chance of appearing1%of analysed past papers
Latest appearanceMay 2025
Most common paperPaper1A
Typical marks1

Common command terms

  • Identify

Recent exam appearances

May 2025Paper1A ["HL"] · TZ132[ 1 ]D3.1.13 (HL)—Puberty control
Practice this objective

Coverage 2025–2025 · Updated 16 Jul 2026

Puberty Begins when Hormonal Signals Activate the Gonads

HL only

Puberty begins when increased hypothalamic GnRH release stimulates the pituitary to release more LH and FSH.

LH and FSH act on the gonads, increasing gamete production and secretion of steroid sex hormones such as testosterone and oestradiol. These hormones drive primary reproductive maturation and secondary sexual characteristics.

Hypothalamus: GnRH ↑ → pituitary: LH/FSH ↑ → ovaries/testes: gametogenesis and sex-steroid secretion ↑ → developmental changes of puberty.

In a typical male pathway, rising LH supports testicular testosterone secretion while FSH contributes to sperm production; testosterone promotes reproductive maturation and secondary traits.

Puberty timing and visible changes vary among individuals; the defining control is the endocrine signal chain, not one external trait.

Puberty control

HL only

Assessment in practice

1 marks
How it is assessed

This objective is assessed through multiple choice, commonly using Identify.

Command terms

Identify

What earns marks

Build the answer around this relationship: The hypothalamus initiates puberty control through increased GnRH release.

Representative question

Question 1

[Maximum number: 1]

What controls the developmental changes during puberty?

I. Increased release of gonadotropin-releasing hormone (GnRH) by the hypothalamus
II. Luteinizing hormone (LH) leading to increased sex hormone production
III. Gonadotropin-releasing hormone (GnRH) triggering the onset of increased luteinizing hormone (LH)

A

I and II only

B

I and III only

C

II and III only

D

I, II and III

Retrieve the HL Reproduction Route

HL only

HL D3.1 is about ordered mechanisms and evidence judgment: endocrine control, gametogenesis contrast, one-sperm fertilization, early embryo stages, hCG detection, placental exchange, birth feedback, and HRT evaluation.

  • GnRH drives pituitary FSH/LH and sex-hormone production
  • spermatogenesis gives four sperm; oogenesis gives one ovum and polar bodies
  • acrosome entry, cortical block, cleavage, blastocyst, endometrium
  • hCG, placenta, childbirth feedback, and HRT risk-benefit evaluation

HL Human Reproduction

HL only

HL D3.1 moves from reproductive events into control and evidence. The strongest answers keep sequences in order: endocrine axis at puberty, gametogenesis outcomes, fertilization blocks, blastocyst implantation, hCG testing, placental exchange, childbirth feedback, and HRT evaluation.

  • Explain HL mechanisms in order, especially hormone pathways and early-development stages.
  • Compare gametogenesis and fertilization mechanisms using precise structural terms.
  • Evaluate HRT by weighing symptom benefits against risks and evidence quality.

Concept essentials

  • The hypothalamus initiates puberty control through increased GnRH release.
  • GnRH stimulates increased LH secretion from the pituitary.
  • LH promotes increased sex hormone production by the gonads.