How do your hormones work? - Emma Bryce
Over the course of our lifetimes,
our bodies undergo a series
of extraordinary metamorphoses:
we grow,
experience puberty,
and many of us reproduce.
Behind the scenes,
the endocrine system works
constantly to orchestrate these changes.
Alongside growth and sexual maturity,
this system regulates everything
from your sleep
to the rhythm of your beating heart,
exerting its influence over each
and every one of your cells.
The endocrine system relies
on interactions
between three features to do its job:
glands,
hormones,
and trillions of cell receptors.
Firstly, there are several
hormone-producing glands:
three in your brain,
and seven in the rest of your body.
Each is surrounded by
a network of blood vessels,
from which they extract ingredients
to manufacture dozens of hormones.
Those hormones are then
pumped out in tiny amounts,
usually into the bloodstream.
From there, each hormone needs
to locate a set of target cells
in order to bring about a specific change.
To find its targets,
it’s helped along by receptors,
which are special proteins inside
or on the cell’s surface.
Those receptors recognise
specific hormones as they waft by,
and bind to them.
When this happens,
that hormone-receptor combination
triggers a range of effects
that either increase or decrease
specific processes inside the cell
to change the way that cell behaves.
By exposing millions of cells at a time
to hormones
in carefully-regulated quantities,
the endocrine system drives
large-scale changes across the body.
Take, for instance, the thyroid
and the two hormones it produces,
triiodothyronine and thyroxine.
These hormones travel to most
of the body’s cells,
where they influence how quickly
those cells use energy
and how rapidly they work.
In turn, that regulates everything
from breathing rate
to heartbeat,
body temperature,
and digestion.
Hormones also have some of their most
visible—and familiar—effects
during puberty.
In men, puberty begins when
the testes start secreting testosterone.
That triggers the gradual development
of the sexual organs,
makes facial hair sprout,
and causes the voice to deepen
and height to increase.
In women, estrogen secreted from the
ovaries signals the start of adulthood.
It helps the body develop,
makes the hips widen,
and thickens the womb’s lining,
preparing the body
for menstruation or pregnancy.
An enduring misconception around
the endocrine system
is that there are exclusively male
and female hormones.
In fact, men and women
have estrogen and testosterone,
just in different amounts.
Both hormones play a role
in pregnancy, as well,
alongside more than 10 other hormones
that ensure the growth of the fetus,
enable birth,
and help the mother feed her child.
Such periods of hormonal change are also
associated with fluctuations in mood.
That’s because hormones can influence
the production of certain chemicals
in the brain, like serotonin.
When chemical levels shift,
they may cause changes in mood, as well.
But that’s not to say that hormones
have unlimited power over us.
They’re frequently viewed as the main
drivers of our behavior,
making us slaves to their effects,
especially during puberty.
But research shows that our behavior
is collectively shaped
by a variety of influences,
including the brain
and its neurotransmitters,
our hormones,
and various social factors.
The primary function
of the endocrine system
is to regulate our bodily processes,
not control us.
Sometimes disease,
stress,
and even diet can disrupt
that regulatory function, however,
altering the quantity of hormones
that glands secrete
or changing the way that cells respond.
Diabetes is one of the most
common hormonal disorders,
occurring when the pancreas
secretes too little insulin,
a hormone that manages blood sugar levels.
And hypo- and hyperthyroidism
occur when the thyroid gland makes
too little or too much thyroid hormone.
When there’s too little thyroid hormone,
that results in a slowed heart rate,
fatigue,
and depression,
and when there’s too much
thyroid hormone,
weight loss,
sleeplessness,
and irritability.
But most of the time,
the endocrine system manages to keep
our bodies in a state of balance.
And through its constant regulation,
it drives the changes that ultimately
help us become who we are.
