Adrenal gland

Adrenal glands

Adrenal cortex labelled

1818 The Adrenal Glands

Adrenal Steroids Pathways

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Adrenal glands, also known as suprarenal glands, are small, triangular-shaped glands located on top of both kidneys. Their main function is to produce hormones that regulate metabolism, immune system, blood pressure, stress response, and other essential functions.

Structure

The adrenal glands are enveloped in a fatty layer and consist of two main parts: the outer adrenal cortex and the inner adrenal medulla, each responsible for producing different groups of hormones.

Adrenal Cortex

The adrenal cortex produces corticosteroids, which are essential for life. It is divided into three zones: the zona glomerulosa, the zona fasciculata, and the zona reticularis. Each zone produces specific hormones:

• The zona glomerulosa produces aldosterone, which regulates blood pressure and electrolyte balance.
• The zona fasciculata produces cortisol, a hormone involved in the response to stress and metabolism.
• The zona reticularis produces androgens, which are converted to fully functional sex hormones in the gonads.

Adrenal Medulla

The adrenal medulla produces catecholamines, such as adrenaline (epinephrine) and norepinephrine (noradrenaline), which are involved in the body's fight-or-flight response to stress.

Function

The adrenal glands play a crucial role in the body's response to stress. When the body is stressed, the adrenal glands release cortisol, which increases glucose in the bloodstream, enhances the brain's use of glucose, and increases the availability of substances that repair tissues. Adrenaline increases the heart rate, elevates blood pressure, and boosts energy supplies.

Disorders

Several disorders are associated with the adrenal glands, including:

• Addison's disease, characterized by insufficient production of cortisol and aldosterone.
• Cushing's syndrome, caused by excessive cortisol production.
• Adrenal insufficiency, where the adrenal glands do not produce adequate amounts of steroid hormones.
• Pheochromocytoma, a rare tumor of the adrenal medulla that causes excess production of adrenaline and norepinephrine.
• Congenital adrenal hyperplasia, a group of genetic disorders that affect the adrenal glands.

Diagnosis and Treatment

Diagnosis of adrenal gland disorders typically involves blood tests, urine tests, imaging tests, and sometimes genetic testing to identify hormonal imbalances and abnormalities in the glands. Treatment varies depending on the disorder and may include medication to replace or regulate hormone levels, surgery to remove tumors, and lifestyle changes to manage symptoms.