The adrenal glands are small, yellowish retroperitoneal organs. These are located on the upper holes of the kidney. The shape of the right adrenal gland is pyramidal whereas the left adrenal gland is crescent. The embryology of the adrenal gland is it is first observed at 6-8 weeks’ gestation that is derived from the mesoderm of the posterior abdominal wall. Thereafter the steroid secretion from the cortex begins. For the biosynthesis of adrenal steroids, adrenal cortex secretes aldosterone, cortisol, and adrenal androgen hormones from different zones of adrenal cortex. Aldosterone accounts for 90% of the mineralocorticoid activity, with some activity that is contributed by deoxycorticosterone, corticosterone, and cortisol. Zona fasciculate secrete cortisol, which is a principal glucocorticoid. Cortisol is responsible for majority of the glucocorticoid activity. Various sex steroids such as DHEA, DHEAS, androstenedione, and 11-hydroxyandrostenedione are secreted by the zona reticularis layer of adrenal cortex. The adrenal medulla secretes 80% of epinephrine, and 20% of norepinephrine with minimal amounts of dopamine.