In animals, chemical coordination is achieved through the agency of hormones which function as chemical messengers or informational molecules. Hormones are secreted in a very small amount by specialized tissues in the body called endocrine glands. these glands are ductless and pour their secretions directly into blood. Blood transports themto the target tissues/organs. Hormones coordinate the activities of living organisms and also their growth. For example, pancreas secrets two hormones - insulin and glucagon.