A hormone is any member of a class of signaling molecules produced by glands in multicellular organisms that are transported by the circulatory system to target distant organs to regulate physiology and behaviour. Hormones have diverse chemical structures, mainly of 3 classes: eicosanoids, steroids, and amino acid/protein derivatives. The glands that secrete hormones comprise the endocrine signaling system. The term hormone is sometimes extended to include chemicals produced by cells that affect
The use case model consists of two artifacts: the use case diagram, which is a graphical representation showing which actors can operate which use cases, and the use case description (sometimes called the use case narrative), which is the text-based, detailed, step-by-step interactions and dialogue between the actor and the system.
Drawing Actors and Use Cases. The main purpose of a use case diagram is to show who interacts with your system, and the main goals they achieve with it. Create Actors to represent classes of people, organizations, other systems, software or devices that interact with your system or subsystem.