Page 50 - (DK) Help Your Kids with Growing Up: A No-Nonsense Guide to Puberty and Adolescence

48 MALE PUBERT Y

Male hormones SEE ALSO
‹
46–47 What is puberty?
Changing body 50–51 ›
Hormones are chemicals, produced in the body, which send Testicles 52–53 ›
instructions to cells. Each hormone can only affect specific target Breaking voices 56–57 ›
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 ▽ Chemical messsengers
an increase in the level of the primary sex hormones in males and females – Blood vessels transport hormones
testosterone in males, and oestrogen in females. As puberty continues, these from the endocrine glands to
and other hormones regulate and monitor each stage of development. specific cells around the body,
where they stimulate change.
6. The brain detects the increased levels of
testosterone in the blood and responds by
releasing less GnRH. Less GnRH means less FSH
1. The hypothalamus in and LH, which in turn prompts the testicles to
the brain releases GnRH. release less testosterone, 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 5. An increased amount of
travel in the
bloodstream to testosterone in the bloodstream
the testicles. travels back up to the brain.
Hormone Where produced Effects on the body

GnRH In the hypothalamus Stimulates the pituitary gland
in the brain to release LH and FSH

LH and FSH In the pituitary Stimulates testosterone and
gland in the brain sperm production in the
testicles
Testosterone In the testicles Stimulates changes at
puberty, such as the
4. The arrival of
LH and FSH in the enlargement of the
testicles prompts testicles and penis
the production
of testosterone
and sperm. ◁ 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.

048-049_Male_hormones.indd 48 24/03/2017 17:15