Video Transcript
Which of the following best
describes the primary function of hormones belonging to the glucocorticoids
group? To regulate the development of
sexual organs and characteristics. To increase the activity of the
immune system and initiate an inflammatory response. To respond to signals from the
sympathetic nervous system and decrease the heart rate. Or to regulate the metabolism of
glucose in the body to maintain normal concentrations of blood glucose.
Let’s remove these options for now
and dive into the exciting world of glucocorticoid hormones. You may recall that hormones are
chemical messengers which travel throughout an organism’s body, often in the blood,
to maintain homeostasis and regulate behavior. On top of our kidneys, we have a
pair of glands called the adrenal glands. Because of their location, they
look a bit like little hats. The adrenal glands release many
different hormones, including one particular group called glucocorticoids.
The word glucocorticoid sounds
really complicated. But when we break it down, it
actually gives us some useful information about what these hormones are and what
they do. Gluco- comes from the word glucose,
so that tells us that their function has something to do with glucose. The “cort” part tells us that
they’re released by the cortex of the adrenal glands. And the -oid at the end tells us
that they’re steroid hormones. But we don’t need to worry too much
about that for this question. Now, we’ve already said that the
function of glucocorticoids involves glucose, and what they actually do is help to
regulate the levels of glucose in the blood. The most important example of a
glucocorticoid in the human body is cortisol; it’s essential to life.
When the body is under stress, it
requires more energy to cope. This causes the blood glucose
concentration to fall, as glucose is the primary source of energy. If it falls below normal levels,
cortisol is released from the cortex of the adrenal glands into the blood. It travels to target cells, such as
fat cells and muscle cells, and alters their metabolism, causing fats and proteins
to be broken down into metabolites. These metabolites then move into
the blood, where they’re transported throughout the body and in particular are
absorbed by cells of the liver.
Here, the metabolites are converted
into glucose, which is then released into the blood. This process is called
gluconeogenesis, and it helps to bring the blood glucose concentration back up to
normal levels. This is important because if
there’s not enough glucose in the bloodstream, cells won’t be able to break it down
to release energy in the process of cellular respiration. Cortisol has many other
functions. For example, it reduces
inflammatory responses, maintains our blood pressure, and even regulates our sleep
cycle.
Now, let’s return to our
multiple-choice options and determine which one is correct. To regulate the development of
sexual organs and characteristics. The adrenal cortex releases small
volumes of sex hormones, such as androgens and estrogens, which are responsible for
this. But glucocorticoids are not
involved, so this statement is incorrect. To increase the activity of the
immune system and initiate an inflammatory response. Glucocorticoids actually have the
opposite role. They reduce inflammation, so this
statement is also incorrect.
To respond to signals from the
sympathetic nervous system and decrease the heart rate. In actual fact, signals from the
sympathetic nervous system cause adrenaline and noradrenaline to be released, which
act to increase the heart rate. Again, glucocorticoids are not
involved, so this statement is incorrect too. To regulate the metabolism of
glucose in the body to maintain normal concentrations of blood glucose. As we’ve talked about,
glucocorticoids, such as cortisol, act to restore blood glucose levels if they fall
too low. Therefore, this statement must be
correct.
We have therefore determined that
the primary function of hormones belonging to the glucocorticoids group is to
regulate the metabolism of glucose in the body to maintain normal concentrations of
blood glucose.
