As degranulation occurs, it causes the mast cell or basophil to release a series of chemicals that orchestrate the allergic reaction. Within every mast cell or basophil are 500 to 1500 granules containing more than thirty different allergy-causing chemicals.
Urban design is an inter-disciplinary subject that unites all the built environment professions, including urban planning, landscape architecture, architecture, civil and municipal engineering.
Systems design is the process of defining the architecture, components, modules, interfaces, and data for a system to satisfy specified requirements. Systems design could be seen as the application of systems theory to product development. There is some overlap with the disciplines of systems analysis, systems architecture and systems engineering.