Exudates may be formed as part of the inflammatory phase of tissue repair. For instance, inflammation and exudation may occur in wounds that are large because the skin barrier is disrupted and therefore foreign bodies such as bacteria can easily gain entry. When this happens, neutrophils are transported to the injured site to destroy bacteria. Apart from neutrophils, macrophages, monocytes, and polymorphonuclear cells are also active in participating in the inflammatory response to an infection of the wound. These cells are called inflammatory cells. Thus, the exudate would contain dead and dying bacteria, inflammatory cells, and cell debris making the exudate viscous and opaque. This type of exudate is said to be purulent. Its color is characteristically yellowish, grayish or greenish in color. Severe infection of the wound would lead to releasing more exudate, which could mean prolonged wound healing.