Adrenal Glands: Where They Are Located, What They Do, and What Diseases Occur

There is a popular idea that the adrenal glands are primarily about social-media "burnout." In reality, they are two small glands above the kidneys whose hormones maintain blood pressure, blood sugar, salt balance, and the stress response. Let us go through in order where they are, what they produce, and in which diseases they break down.

Adrenal Glands: Where They Are Located and How They Are Structured

The adrenal glands are paired endocrine glands directly above the upper pole of each kidney. Their size is modest: about 5 cm in length, 3 cm in width, up to 1 cm in thickness, with a total mass in an adult of 7 to 10 g, and a yellowish color. The right one resembles a pyramid, the left one resembles a crescent or sickle and is slightly larger. Internally the gland is heterogeneous: the cortex and the medulla are two different structures with different tasks, and they work under the control of the nervous system.

Cortex and Medulla: How They Differ

The adrenal cortex is a factory of steroids, corticosteroids. It has three layers, and each has its own output.

• Zona glomerulosa — mineralocorticoids: aldosterone and the less active corticosterone and deoxycorticosterone.
• Zona fasciculata — glucocorticoids: cortisol and cortisone.
• Zona reticularis — androgens, precursors of estrogens.

The medulla is structured differently: in essence it is a specialized sympathetic plexus that releases hormones directly into the blood, bypassing the synapse. Its cells produce adrenaline and noradrenaline.

Adrenal Hormones and What They Are Responsible For

Mineralocorticoids enhance the reabsorption of sodium in the kidneys and the excretion of potassium. Glucocorticoids stimulate the formation of glucose from fats and amino acids, suppress inflammatory, immune, and allergic reactions, restrain the growth of connective tissue, and increase the excitability of the nervous system. Cortical androgens affect secondary sexual characteristics: an excess leads to virilization, a deficiency leads to hair loss.

Catecholamines raise blood pressure, strengthen and increase the rate of heart contractions, dilate the bronchi and pupils, and raise blood sugar levels. At rest, little of them is released; under stress, secretion rises sharply. The bottom line: the functions of the adrenal glands are to turn food into energy and to maintain blood sugar, salt, water, blood pressure, the stress response, and the timing of sexual development.

Kidneys and Adrenal Glands: Why the Glands Are Located Nearby

The proximity is not accidental: the inferior suprarenal artery is a branch of the renal artery, and two more come from the inferior phrenic artery and from the abdominal aorta. The outflow is also nearby: the right suprarenal vein drains into the inferior vena cava, the left into the left renal vein. The glands are located next to the kidneys and receive blood including from the renal artery.

Adrenal Diseases and Their Main Signs

The principle is one: hormones become either too much or too little, and the symptoms depend on which ones exactly and to what extent.

Addison's disease — the cortex does not produce enough cortisol. Signs: extreme fatigue, darkening of the skin, loss of appetite and weight, abdominal pain, nausea and vomiting, craving for salty foods, dizziness on standing up, muscle weakness and cramps, headache, thirst and frequent urination, anxiety and depression. Adults aged 30–50 are affected more often, and it also occurs in children. The most common cause is an immune attack on one's own glands; less often infections (tuberculosis, meningitis, influenza, cytomegalovirus, HIV) and removal of the glands.

Other diseases: Cushing's syndrome — an excess of cortisol, often due to steroid medications; an aldosterone-producing adenoma with severe hypertension; pheochromocytoma — tumors that produce adrenaline; adrenal cancer; congenital adrenal hyperplasia. The causes are medications, a malfunction in another gland, mutations, infections; sometimes no cause is found.

How Adrenal Activity Is Assessed and When a Doctor Is Needed

Adrenal activity is assessed by a doctor: history-taking, examination, then blood, urine, or saliva tests for hormones. There is also the Synacthen test — blood is taken before and after an injection of the drug, and the response of the glands is observed. Tumors are sought using X-ray, CT, or MRI. Adults are referred to an endocrinologist, children more often to a pediatrician.

Feeling unwell on its own is not a reason to call an ambulance. 103 or 112 — if a person with Addison's disease has sharply deteriorated: rapid pulse, severe dizziness on standing up, severe abdominal or flank pain, muscle weakness, pain or spasms, persistent headache, nausea or vomiting, severe drowsiness, irritability or confusion, seizures, loss of consciousness. This may be the onset of an adrenal crisis, in which severe dehydration, a drop in blood pressure, stroke, and cardiac arrest can occur.

This material is for reference: it explains how the gland is structured but does not replace a doctor's consultation — a diagnosis is not made from an article.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer