Video Transcript
State the adrenal hormone being described. This is the main hormone released by the adrenal cortex to regulate the balance of
salt and water in the body by promoting the retention of salt and water by the
kidneys.
This question is asking us to identify a specific hormone that is secreted from the
human adrenal glands. You may recall that a hormone is a chemical messenger secreted from organs called
endocrine glands directly into the blood to trigger a specific effect. Each of the two kidneys usually has an adrenal gland located above it. Let’s take a closer look at a cross section through one adrenal gland and identify
some of the key hormones it releases.
Each adrenal gland is made up of two key regions responsible for releasing different
hormones with different target tissues and functions, surrounded by a protective
capsule. The innermost region is called the adrenal medulla, and it is responsible for
releasing hormones that help us to respond to stressful situations through the
fight-or-flight response. The main hormones released from the adrenal medulla are called adrenaline, sometimes
epinephrine, and noradrenaline, sometimes called norepinephrine.
Surrounding the adrenal medulla is the adrenal cortex, which releases hormones that
are vital to our survival. The hormone being described in the question is one released by the adrenal
cortex. One such example of a hormone released from the adrenal cortex is aldosterone, which
belongs to a group of hormones called mineralocorticoids. The prefix mineral- gives us a clue as to the function of aldosterone, regulating the
reabsorption of minerals, like sodium. This process occurs in the kidneys, which are located conveniently close to the
adrenal glands themselves. So aldosterone does not have far to travel in the blood to cause its effect.
Aldosterone triggers the reabsorption of sodium into the blood and the excretion of
potassium. Sodium is reabsorbed along with chloride ions in the form of a salt. Increasing the concentration of salt in the blood in turn influences the reabsorption
of water. This helps the body to regulate a fine balance of salt and water in the blood.
This means that we have found the correct answer to this question, asking about a
hormone released from the adrenal cortex which helps regulate salt and water balance
in the body. The hormone being described is aldosterone.
