What are adrenal glands?

The adrenal glands are two small glands, one located on the upper end of each kidney. They are about 5cm long and 2.5 cm wide and weigh about 5 grams each. They resemble a triangular shape and have a yellowish-brown color.

The right gland sits next to the inferior vena cava (the vein that carries blood from the legs and abdomen back to the heart) and typically has one adrenal vein that empties directly into it. The left gland sits next to the aorta (the artery that takes blood from the heart and transports it to other areas of the body), colon, stomach and spleen. It has a single adrenal vein that empties into the renal vein. Both the right and left adrenal glands receive blood from numerous blood vessels coming from the diaphragm, kidney vessels and aorta.

Adrenal glands have two layers: the cortex and the medulla. Each layer has a different origin, structure and function. The cortical portion (also called the adrenal cortex) is made up of three successively layered portions. Each portion is specialized in the production of particular hormonal steroids. The glomerular region (outermost layer) produces aldosterone and other hormones such as mineralocorticoid, essential for the regulation of salt and water in the body parts. The sorted portion (intermediate layer) produces cortisone, cortisol and corticosterone (the active glucocorticoid replacement carbohydrate) essential for metabolism and immune system suppression. Finally, the mesh (innermost layer) provides the production of sex hormones, mainly androgens, but also progesterone and estrogen.

The medulla (or adrenal medulla) is located within the adrenal gland and is enveloped by the cortical portion. It consists of irregular cellular cords that produce two catecholamines (neurotransmitters), adrenaline and noradreanalina. These hormones have a “fight or flight” response and trigger the body in certain situations (exercise, anxiety, and so on). The secretion of hormones of the adrenal cortex, and in particular that of the glucocorticoids, is controlled by the hormone pituitary ACTH.

When the glands produce more or less hormones than required by the body, disease conditions may occur. Adrenal insufficiency occurs when the adrenal gland is not producing enough hormones. It can be fatal if the individual does not seek proper medical treatment. On the other hand, when the adrenal gland makes too much of any hormone, it can lead to the following conditions: cushing’s syndrome (too much cortisol), primary hyperaldosteronism (too much aldosterone), virilizing syndromehormone (too much androgen), pheochromocytoma (too much adrenaline) and paraganglioma (too much adrenaline). In any case, determining the most appropriate form of treatment is vital in order to prevent further complications from arising.


What function do adrenal glands serve?

The adrenal glands primary function is to secrete different hormones essential for conducting several physiological functions. Endocrine secretion is entered directly into the bloodstream. This type of secretion is distinguished from exocrine secretion, where the hormone is placed into a natural cavity of the body or released outside, as in the case of gastric juices of the stomach.

Adrenal glands produce hormones that the body cannot function without, including sex hormones and cortisol. Cortisol helps an individual respond to stressful situations and helps regulate metabolism (among other important functions); while aldosterone helps control blood pressure levels from escalating.