The adrenal cortex secretes more than two dozen different steroid hormones called the adrenocortical steroids, or simply corticosteroids. The adrenal cortex is divided into three major zones or regions each of which secretes a different type of corticosteroid. The outer region is the zona glomerulosa, which produces mineralocorticoids. The middle zone is the zona fasciculata, which accounts for the bulk of the cortical volume and produces glucocorticoids. The innermost, and smallest region, is the zona reticularis, which produces small quantities of the sex hormones.