Adrenal glands: definition, location, anatomy

Definition: what are the adrenal glands?

These glands produce many hormones such as cortisol and adrenaline, necessary for the proper functioning of the body. They are two in number and each “cap” a kidney. They consist of two superimposed parts: on the periphery, a yellow zone called “adrenal cortex” or “adrenal cortex” and, in the center, a red nucleus called “adrenal medulla”. Each of these two areas specializes in production of hormones essential for life.

What is the role of the adrenal glands?

The adrenal glands are responsible for synthesize and release many hormones into the bloodstream essential for the proper functioning of the body.

► The adrenal medulla secretes norepinephrine and adrenaline, two hormones that speed up the heart rate and increase blood pressure. They are more particularly produced in times of stress.

► “The adrenocortical part produces hormones called “corticosteroids” (Cortisol), mineralocorticoids (Aldosterone), and androgens (Testosterone and DHEA sulphate), explains Dr. Pierre Nys, endocrinologist in Paris. Among them, cortisol which participates in the regulation of blood sugar and has an anti-inflammatory action, testosterone (in partnership with the gonads) a male sex hormone which is involved in sexual development and reproduction, and aldosterone whose role is to control sodium retention and potassium leakage, thus regulating blood pressure.

Diagram of the adrenal glands

What are the diseases of the adrenal glands?

“There are more than 20 diseases linked to dysfunction of the adrenal glands”, says Dr. Nys. Among :

• There Addison’s diseasewhen the production of cortisol is stopped.
• The irenal failure.
• There Cushing’s disease, when cortisol is produced in excess.
• There Conn’s disease caused when aldosterone is in excess.
• THE pheochromocytomas : a tumor that abnormally secretes two types of hormones: adrenaline and noradrenaline. As a result, an increased risk of diabetes, an increase in blood pressure, a hypokalemia (lack of potassium in the blood) and chronic constipation. THE tumors are benign in 90% of cases and surgery allows the cure. 10% of pheochromocytomas are of malignant origin and can lead to metastases.

Dysfunction of the adrenal glands causes different symptoms:

• Fatigue
• Digestive disorders
• Weight loss or gain
• Blood pressure disorder (significant increase or decrease)
• Decreased libido
• Joint pain

To detect dysfunction of the adrenal glands, the doctor first performs a clinical examination via an interrogation of the symptoms felt. “Blood and urine tests can be carried out to analyze the level of certain hormones in the body. A drug treatment will be prescribed to you according to the hormone to be compensated”, explains Dr. Nys.

Thanks to Dr Pierre Nys, endocrinologist in Paris.