The glands in human body are of two types. One is exocrine glands and the other is endocrine glands. The exocrine glands produce fluid secretions that are delivered by tubes or ducts either to the body surface for example glands of skin or to the inner regions where these are required for example pancreas delivers its pancreatic juice to the intestine for digesting food etc. Endocrine glands produce secretions called hormones that are not carried by ducts but are passed into the blood stream and carried to the target area by blood circulation. The following endocrine glands are present in human body; pituitary gland, pancreas (islets of langerhans), thyroid gland, adrenal glands, and gonads. The function of endocrine glands is very much inter-related. Several of the hormones produced by them serve only to alter the functions of other endocrine glands. They serve as double check automatic control over one another. The pituitary gland is known as master gland in the body and plays an important role in several ways. It has certain hormones which have direct action on the body for example the growth hormone. Thyroid gland is located in the neck and fits closely around the from and side of trachea just below the organ of voice of larynx.