Page 32 - (DK) Help Your Kids with Growing Up: A No-Nonsense Guide to Puberty and Adolescence

30 FEMALE PUBERT Y

Female hormones SEE ALSO
‹
28–29 What is puberty?
Changing body 32–33 ›
Hormones are chemicals, produced in the body, that send The menstrual cycle 36–37 ›
instructions to cells. Each hormone can only affect specific target Breasts 40–41 ›
cells, which contain the appropriate receptor for that hormone.

Kickstarting puberty
At the start of puberty, gonadotropin-releasing hormone (GnRH) in the brain signals
to the body that it’s ready to start developing into an adult. GnRH causes an increase ▽ Chemical messengers
in the level of the primary sex hormones in females and males – oestrogen in females, Blood vessels transport hormones
and testosterone in males. As puberty continues, these and other hormones regulate from the endocrine glands to
and monitor each stage of development. specific cells around the body,
where they stimulate change.
6. The brain detects the increased levels of
oestrogen in the blood and responds by
1. The hypothalamus in releasing less GnRH. Less GnRH means less
the brain releases GnRH. FSH and LH, which in turn prompts the
ovaries to release less oestrogen, in order
to regulate the amount in the body.
Blood vessel
2. GnRH stimulates the
pituitary gland to release
luteinizing hormone (LH)
and follicle-stimulating Endocrine Hormones
hormone (FSH). gland

Target cell
3. LH and FSH
travel in the 5. An increased amount of
bloodstream oestrogen in the bloodstream
to the ovaries. travels back up to the brain.

Hormone Where produced Effects on the body
GnRH In the hypothalamus Stimulates the release
in the brain of LH and FSH

4. The arrival of LH and FSH In the pituitary gland Stimulates oestrogen and egg
LH and FSH in in the brain development in the ovaries
the ovaries
prompts the
production of Oestrogen In the ovaries Stimulates changes at
oestrogen puberty, such as pubic and
and egg underarm hair growth
development. and breast development

◁ Feedback loop
The body’s hormone levels are monitored by a feedback loop.
The amount of a hormone in the bloodstream signals to the
brain whether more or less is required.

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