Understanding the Adrenal Glands: Small but Powerful Organs

The adrenal glands are two small, triangular-shaped organs that sit on top of your kidneys — one on each side. Despite their small size, they play an enormous role in keeping your body balanced and healthy. The adrenal glands are responsible for producing vital hormones that regulate your metabolism, immune system, blood pressure, and response to stress.

Anatomy of the Adrenal Glands

Each adrenal gland has two distinct parts that perform different functions:

1. The Adrenal Cortex — the outer layer of the gland, which produces several essential steroid hormones.

2. The Adrenal Medulla — the inner core, which produces adrenaline-like hormones that help the body respond to stress.

Hormones Produced by the Adrenal Cortex

The adrenal cortex is divided into three zones, each producing different hormones:

1. Zona Glomerulosa – Mineralocorticoids

The main hormone produced here is aldosterone. Aldosterone helps control salt and water balance, which in turn maintains blood pressure and blood volume. When aldosterone levels are low, your blood pressure can drop; when high, it may lead to fluid retention and hypertension.

2. Zona Fasciculata – Glucocorticoids

The primary hormone here is cortisol, often called the “stress hormone.” Cortisol has many roles:

• Helps control blood sugar levels

• Aids metabolism of proteins, fats, and carbohydrates

• Suppresses inflammation

• Regulates sleep–wake cycles

• Supports your body’s response to physical and emotional stress

3. Zona Reticularis – Androgens

Produces small amounts of sex hormones such as DHEA (dehydroepiandrosterone). These hormones are precursors that can be converted to estrogen and testosterone. Though minor compared to gonadal hormones, they play a role in puberty, mood, and libido.

Hormones Produced by the Adrenal Medulla

The adrenal medulla functions like part of the nervous system. It releases catecholamines, primarily:

• Adrenaline (epinephrine)

• Noradrenaline (norepinephrine)

These hormones are responsible for the “fight or flight” response — preparing your body to respond to sudden stress. They:

• Increase heart rate

• Raise blood pressure

• Dilate airways in the lungs

• Boost energy by increasing glucose release from the liver

Common Disorders of the Adrenal Glands

Several conditions can affect adrenal function:

• Adrenal Insufficiency (Addison’s Disease): The adrenal glands fail to produce enough cortisol and aldosterone, leading to fatigue, weight loss, and low blood pressure.

• Cushing’s Syndrome: Excess cortisol production causes weight gain, muscle weakness, and high blood pressure.

• Conn’s Syndrome (Primary Hyperaldosteronism): Overproduction of aldosterone leads to high blood pressure and low potassium.

• Pheochromocytoma: A rare tumour of the adrenal medulla causing excessive adrenaline secretion and sudden spikes in blood pressure.

• Adrenal Incidentaloma: An unexpected adrenal mass found on imaging, which may require evaluation to rule out hormone secretion or malignancy.

Conclusion

The adrenal glands are tiny but vital organs that keep your body functioning smoothly. They regulate your stress response, metabolism, immune balance, and blood pressure. Disorders of the adrenal glands can have widespread effects, so early recognition and management are essential. Understanding how these glands work helps both patients and clinicians appreciate the delicate hormonal balance that supports daily life.