Progression of the exocrine system over time, from its formation to a mature structure. The exocrine system is a system of hormones and glands, where the glands secrete straight to a target site via ducts or tubes. The human exocrine system includes the salivary glands, sweat glands and many glands of the digestive system. [ GOC:bf http://en.wikipedia.org/wiki/Exocrine_gland ]