The adrenal or supra-renal glands are paired, pyramid-shaped glands located above the kidney and in line with the twelfth rib. When the body experiences stress, these glands respond by secreting hormones. The synthesis of these hormones requires stored cholesterol and fatty acids which give the glands a yellow tinge. A fibrous capsule and fat cushion these glands. The adrenal gland contains two regions, each with distinct functions. The adrenal cortex is the outer layer that forms the bulk of the gland and synthesizes hormones such as corticosteroids that promote long-lasting responses to stress. It contains three lipid-laden cell layers: the zona glomerulosa, the top layer; the zona fasciculata, the middle layer; and the zona reticularis, the innermost layer. The adrenal medulla is the interior layer that is encapsulated by the cortex. It is composed of nervous tissue and contains spherical chromaffin cells surrounding capillaries. Chromaffin cells synthesize catecholamines, hormones that promote more immediate and brief effects, such as the fight-or-flight response.