Structure and Function: Adrenal Glands

Each adrenal gland has two parts. The cortex (outer layer) is controlled by the pituitary gland and produces several corticosteroid hormones, the most important of which affect metabolism and blood pressure. The cortex also secretes small amounts of male sex hormones (androgens). The medulla (core) influences the autonomic nervous system by releasing the hormones epinephrine (adrenaline) and norepinephrine (noradrenaline), which increase heart activity and blood flow in response to excitement or stress.

Structure of the adrenal gland

The adrenal glands rest on pads of fat above the kidneys. Each gland has an outer cortex, which makes up 90 per cent of its weight, and an inner medulla.

Adrenal hormones

The corticosteroid hormones cortisol and aldosterone and small amounts of male sex hormones are secreted by the cortex. The medulla secretes epinephrine (adrenaline) and norepinephrine (noradrenaline).

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

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