The hormonal or endocrine system represents one of the two great control systems in the body. The nervous system is the other. The nervous system exerts its control by actually sending nerve fibres to the various organs, but the hormonal system exerts its control at a distance. The endocrine glands release their secretions (hormones or ‘chemical messengers’) directly into the blood stream. The blood then carries the hormones to every part of the body. The nervous and endocrine systems, although apparently so different, are not entirely separate. They come together in the connection between the hypothalamus and the pituitary gland.