The mast cells create this reaction by releasing chemicals, called chemotactic factors, that then attract many other inflammatory cells to the site. These cells include: eosinophils, neutrophils, and lymphocytes. Once theyâve arrived, each one of these cells contributes to the late phase of the allergic response. Eosinophils generate chemicals similar to those made by mast cells, as well as release more generally toxic substances that irritate the body.
20 Important Characteristics of Urban Community | Sociology. A sociological analysis of urban community contains several salient features. As a rule, in the same country and at the same period, the size of an urban community is much larger than that of a rural community. In other words, urbanity and size of a community are positively correlated. Image Courtesy : upload.wikimedia.org/wikipedia/commons/0/08/Ginza_area_at_Tower.jpg.
The minimum population required to constitute a city differs between countries. In the United States, an urban area is defined as a settlement where 2,500 or more people reside.