Video Transcript
What is the primary function of the
adrenaline, epinephrine, and noradrenaline, norepinephrine, hormones? To balance the mineral and water
contents of the body. To regulate the metabolism of
carbohydrates in the body to maintain normal concentrations of blood glucose. To regulate the development of
sexual organs and characteristics. Or to respond to signals from the
sympathetic nervous system and induce the fight-or-flight response.
The question is asking us about the
function of adrenaline and of noradrenaline, two hormones that are released from the
adrenal glands. So that we can work out which
option is correct, let’s have a look at the main hormones released from the
different regions of the adrenal glands and their functions. The adrenal glands are small
hormone-releasing glands that sit above each of our kidneys. This image shows us a cross section
taking through one of the adrenal glands, showing us that it consists of two main
distinct regions, the adrenal cortex and the adrenal medulla.
These two regions are responsible
for releasing different groups of hormones with different structures and
functions. The adrenal cortex releases three
main groups of hormones. One of these groups are called
mineralocorticoids. The mineralocorticoids are
responsible for balancing the mineral or salt and water levels in the blood by
stimulating the selective reabsorption of sodium and water in the kidneys. Another group of hormones released
by the adrenal cortex are glucocorticoids. Glucocorticoids are partly
responsible for regulating carbohydrate metabolism in the body. For example, glucocorticoids help
to increase the production of glucose from fats and proteins when the human body is
under stress and requires more energy.
Androgens, sometimes known as sex
hormones, are mainly secreted from the ovaries in females and testes in males but
are also released in small quantities from the adrenal cortex. Sex hormones are responsible for
regulating the development of sexual organs. They also control how secondary
sexual characteristics develop when a person reaches puberty. For example, males often start to
grow facial hair during puberty. This is an example of a secondary
sexual characteristic.
The main hormones secreted by the
adrenal medulla are adrenaline, sometimes called epinephrine, and noradrenaline,
sometimes called norepinephrine. These hormones are released when
the adrenal medulla are stimulated by the sympathetic nervous system, which is
responsible for initiating the fight-or-flight response during dangerous or
stressful situations. For example, adrenaline and
noradrenaline can increase the rate and force of your heartbeat when you’re about to
run a race. These hormones can also increase
the rate at which your liver converts glycogen into glucose, increasing your blood
glucose concentration. This can also increase the rate at
which your muscle cells use glucose and cellular respiration to release the energy
required to escape or fight through these stressful situations.
Let’s review our answer options to
see which is correct. We know that the mineral and water
balance in the blood is maintained by mineralocorticoids. Therefore, this is not a function
of adrenaline and noradrenaline. We also know that carbohydrate
metabolism is a function of glucocorticoids, so this cannot be our answer
either. The development of sexual organs
and characteristics is controlled by androgens and the sex hormones that they are
converted into. So this is also not a function of
adrenaline and noradrenaline. Therefore, we can conclude that the
main function of adrenaline and noradrenaline is to respond to signals from the
sympathetic nervous system and induce the fight-or-flight response.
