Light micrograph of a section through an adrenal gland. The gland, which is enclosed in a fibrous collagen capsule (blue), is divided into two components. The outer cortex, which secretes steroid hormones, and the inner medulla, which secretes adrenaline and noradrenaline. The cortex is further divided into three sections. Firstly the thin zona glomerulosa directly beneath the capsule, which secretes aldosterone, a hormone that regulates blood pressure. Beneath this is the zona fasciculata (lighter), which makes glucocorticoid hormones such as cortisol. The zona reticularis (darker) is the innermost layer. It produces androgen sex hormones. There are two adrenal glands, one on top of each kidney. Magnification: x40 when printed at 15cm wide.