Human Anatomy

Adrenal glands

Small, triangular-shaped glands located on top of each kidney that produce hormones essential for regulating metabolism and stress response.

Adrenal glands are endocrine glands that sit atop each kidney and are responsible for the release of various hormones that regulate metabolism, immune response, and stress management. These glands are made up of two distinct parts: the adrenal cortex and the adrenal medulla, each producing different classes of hormones critical for a healthy functioning body.

Terminologia Anatomica

glandulae adrenales

System

Endocrine system

Function

The primary function of the adrenal glands is hormone production, which plays a crucial role in the body's response to stress. The adrenal cortex produces corticosteroids, such as cortisol, which help regulate metabolism, blood sugar levels, and immune response. It also secretes aldosterone, which aids in regulating blood pressure by controlling sodium and potassium levels in the body. The adrenal medulla releases catecholamines, such as adrenaline (epinephrine) and norepinephrine, which prepare the body for 'fight or flight' situations by increasing heart rate, dilating air passages, and mobilizing energy stores. Together, these hormones ensure the body can respond effectively to various physical and emotional stresses.

Location

The adrenal glands are located posterior to the diaphragm, positioned directly on top of each kidney, which makes them well-placed to receive blood flow from the renal arteries. Each gland is roughly 3 to 5 centimeters long and 2 to 4 centimeters wide in adults. The right adrenal gland is typically triangular in shape, while the left gland is more semilunar or crescent-shaped. Their strategic location allows for immediate hormonal response during stressful situations, which is essential to maintaining homeostasis within the body.

Did You Know?

Adrenal glands are sometimes referred to as the 'stress glands' because they secrete hormones in response to stress.
Despite their small size, the adrenal glands are responsible for producing over 50 different hormones.
The adrenal cortex accounts for about 90% of the gland’s total size, but the adrenal medulla is critical during acute stress responses.
Adrenal fatigue is a term used by some to describe symptoms associated with prolonged stress, although it is not a formally recognized medical condition.