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.
First-person narrative. A first person narrative is a mode of storytelling in which a narrator relays events from his or her own point of view using the first person I or we, etc.