Understanding the Adrenal Glands: Anatomy, Function, and Disorders

Explore the vital roles of the adrenal glands, their structure, hormone production, and impact on health.

By Medha deb

Created on Oct 3, 2025

Explore the vital roles of the adrenal glands, their structure, hormone production, and impact on health.

The adrenal glands are two small but critically important structures located above each kidney. These glands play a key role in hormone production and the regulation of many vital body processes, impacting everything from metabolism and stress response to blood pressure and sexual development. This comprehensive guide explores the adrenal glands’ structure, hormonal function, and common disorders, providing a foundation for understanding their significance in the human body.

What Are the Adrenal Glands?

The adrenal glands, sometimes called suprarenal glands, are part of the endocrine system. Each gland sits on top of a kidney and consists of two main parts, each with different functions:

Adrenal Cortex (outer layer): Produces essential steroid hormones.
Adrenal Medulla (inner core): Secretes stress-related catecholamines like adrenaline and noradrenaline.

Despite their small size (about the size of an almond), these glands orchestrate many essential bodily functions by releasing hormones directly into the bloodstream.

Anatomy of the Adrenal Gland

Each adrenal gland is partitioned into two distinct regions:

Adrenal Cortex: Constitutes about 85% of the gland’s weight and is responsible for producing steroid hormones.
Adrenal Medulla: Forms the central 15% and produces catecholamine hormones important for the body’s ‘fight or flight’ responses.

The adrenal cortex is itself divided into three specialized zones, each synthesizing different kinds of steroid hormones:

Zona Glomerulosa (outermost): Produces mineralocorticoids (e.g., aldosterone) responsible for salt and water balance.
Zona Fasciculata (middle): Synthesizes glucocorticoids (e.g., cortisol) that manage stress, metabolism, and immune function.
Zona Reticularis (innermost): Creates androgens (precursors to sex hormones like testosterone and estrogen).

Layers and Hormones of the Adrenal Cortex
Zone	Main Hormone(s) Produced	Primary Function
Zona Glomerulosa	Aldosterone (Mineralocorticoid)	Regulates sodium and potassium; controls blood pressure
Zona Fasciculata	Cortisol (Glucocorticoid)	Regulates metabolism, stress response, and immune function
Zona Reticularis	Androgens (DHEA, others)	Influence sexual development and body hair
Medulla	Adrenaline, Noradrenaline	Manages fight-or-flight and acute stress responses

Hormones Produced by the Adrenal Glands

Key Hormones of the Adrenal Cortex

Aldosterone: Maintains electrolyte balances by promoting sodium retention and potassium excretion, thus influencing blood pressure.
Cortisol: The chief glucocorticoid, cortisol manages metabolism, stress response, and inflammation. Its levels vary throughout the day and rise in response to stress.
Androgens: Though less potent than those produced by the gonads, adrenal androgens contribute to the development of secondary sexual characteristics and are precursors for estrogen and testosterone.

Key Hormones of the Adrenal Medulla

Adrenaline (Epinephrine): Accelerates heart rate, increases blood flow to muscles, and raises blood sugar—preparing the body for rapid actions in emergencies.
Noradrenaline (Norepinephrine): Works closely with adrenaline, assisting in the regulation of blood pressure and the acute stress (fight-or-flight) response.

Regulation of Adrenal Hormone Production

The adrenal glands do not work in isolation. Their activity is regulated by complex hormonal feedback systems:

Hypothalamic-Pituitary-Adrenal (HPA) Axis: The hypothalamus in the brain releases CRH (corticotropin-releasing hormone), which prompts the pituitary gland to release ACTH (adrenocorticotropic hormone).
ACTH stimulates the adrenal cortex to produce cortisol and, to a lesser extent, androgens.
Renin-Angiotensin-Aldosterone System (RAAS): Regulates aldosterone production primarily through kidney-sensed changes in blood pressure, volume, or sodium concentration.

This tight hormonal control allows the body to quickly adapt to physical and psychological stress, as well as maintain essential everyday functions like metabolism and blood pressure regulation.

Common Adrenal Gland Disorders

Several medical conditions can disrupt the normal functioning of the adrenal glands, leading to underproduction or overproduction of hormones. Some of the primary adrenal disorders include:

Addison’s Disease (Adrenal Insufficiency)

Occurs when the adrenal cortex does not produce enough cortisol and/or aldosterone.
Can be caused by autoimmune reactions, infections, or damage to the glands.
Symptoms include: fatigue, weight loss, abdominal pain, low blood pressure, skin darkening, and salt cravings.
Treatment often involves hormone replacement therapy.

Cushing’s Syndrome

Results from prolonged high levels of cortisol, either from excessive adrenal production or external sources like steroid medication.
Symptoms include: rapid weight gain (especially in the face, abdomen, and back), high blood pressure, thinning skin, and muscle weakness.
Treatment depends on the underlying cause, such as reducing steroid use or surgical removal of adrenal tumors.

Congenital Adrenal Hyperplasia (CAH)

A group of inherited disorders where enzymes needed for hormone production are deficient, leading to altered levels of cortisol, aldosterone, and androgens.
May cause ambiguous genitalia in newborns, early puberty, and imbalances in salt and fluid levels.
Treatment usually involves lifelong hormone replacement.

Pheochromocytoma

A rare tumor of the adrenal medulla, resulting in excessive production of adrenaline and noradrenaline.
Leads to episodic high blood pressure, headaches, rapid heartbeat, and sweating.
Surgical excision is the primary treatment.

Adrenal Incidentaloma and Other Tumors

Some adrenal tumors are detected incidentally during imaging for other conditions.
Most are benign and do not secrete excessive hormones.
Malignant tumors, while rare, require specialized management and treatment.

Symptoms of Adrenal Gland Disorders

The symptoms of adrenal problems can vary depending on the specific disorder, but may include:

Unexplained weight loss or gain
Fatigue or muscle weakness
Changes in skin coloration (darkening)
High or low blood pressure
Abdominal pain
Excessive hair growth or hair loss
Salt cravings or dehydration
Mood swings, anxiety, or depression

Diagnosis of Adrenal Gland Disorders

Diagnosing adrenal disorders typically involves a combination of the following:

Blood and Urine Tests: Measure hormone levels (e.g., cortisol, aldosterone, ACTH, androgens).
Stimulation or Suppression Tests: Assess how the adrenal glands respond to specific stimulating or suppressing agents.
Imaging Studies: CT scans, MRI, or ultrasound can detect tumors or structural abnormalities.
Genetic Testing: Used in conditions like CAH to identify enzyme deficiencies.

Treatment of Adrenal Gland Disorders

Treatment depends on the underlying cause of the disorder:

Medications: Hormone replacement (for insufficiency), inhibitors to control hormone overproduction, or medications addressing autoimmune causes.
Surgery: Removal of tumors or, in some K cases, the affected adrenal gland.
Patient Education: Individuals with adrenal insufficiency may require emergency hydrocortisone injections during illness or injury.

Living with Adrenal Gland Conditions

Most people with adrenal gland conditions can lead healthy, active lives with proper management. This often involves:

Regular monitoring of hormone levels
Adhering to medication regimens
Wearing medical alert identification for emergencies
Maintaining a healthy lifestyle and stress management strategies

Tips for Maintaining Adrenal Health

Eat a balanced, nutrient-rich diet
Exercise regularly, but avoid overtraining
Get adequate sleep
Manage stress with mindfulness or relaxation techniques
Stay hydrated and monitor blood pressure if at risk
Consult with healthcare providers regularly, especially if you have chronic health conditions

Frequently Asked Questions (FAQs)

What is the main function of adrenal glands?

The adrenal glands produce hormones that help regulate metabolism, response to stress, blood pressure, immune function, and sexual development.

Can you live without your adrenal glands?

It is possible to live without adrenal glands, but lifelong hormone replacement is required. Without hormones like cortisol and aldosterone, critical body processes cannot function properly.

What are symptoms of adrenal gland problems?

Symptoms depend on the type of disorder and may include fatigue, abnormal blood pressure, unexplained weight changes, skin changes, and mood disturbances.

How are adrenal gland disorders diagnosed?

Diagnosis is based on blood, urine, and imaging tests that measure hormone levels and gland structure, sometimes supplemented with genetic tests when needed.

When should I see a doctor about my adrenal glands?

If you experience unexplained symptoms like persistent fatigue, dramatic changes in weight, skin discoloration, or abnormal blood pressure, consult a healthcare professional for evaluation.

Key Takeaways

The adrenal glands are vital for hormone balance, stress adaptation, and overall health.
Disorders can result from both under- and overproduction of adrenal hormones.
Timely diagnosis and treatment enable most individuals to manage adrenal-related disorders effectively.

References

Author

medha deb

Medha Deb is an editor with a master's degree in Applied Linguistics from the University of Hyderabad. She believes that her qualification has helped her develop a deep understanding of language and its application in various contexts.

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