Pleural fibrous adhesions resulting from repaired fibrinous pleuritis in a pig. One refers to inflammatory exudate, the other the product of a repair process. Exudate is dominated by collections of neutrophils. Exudate varies from yellow white to gray white and watery to viscous in consistency. Pus is a term used to describe an accumulation of purulent exudate.
Suppuration refers to the process of accumulation of purulent or suppurative exudate.
An abscess is a circumscribed collection of pus. Accumulation of large numbers of neutrophils in tissues is associated with neutrophil necrosis and neutrophil-induced tissue damage. Occurs commonly in hypersensitivity diseases and in metazoon parasite infestations. Severe blood vessel injury or diapedesis is the common mechanism involved. Often associated with necrotizing inflammatory reactions.