After extravasation, leukocytes emigrate in the tissue towards the site of injury is called as-

(Chemotaxis) (53-57-R) (136-138-HM) (37-Basic pathology 8th)Chemotaxis - After extravasation, leukocytes emigrate in tissues towards the site of injury by a process called chemotaxis, defined most simply as locomotion oriented along a chemical gradientMost common exogenous agents are bacterial products.* In the early stage of inflammation, the rate of flow of blood is increased due to vasodilatation. But subsequently, there is slowing or stasis of bloodstream. With stasis, changes in the normal axial flow of blood in the microcirculation take place. The normal axial flow consists of a central stream of cells widens and peripheral plasma zone becomes narrower because of the loss of plasma by exudation. This phenomenon is known as MARGINATION. As a result of this redistribution, the neutrophils of the central column come close to the vessel wall; this is known as PAVEMENT (137-HM)* Simultaneous to the emigration of leucocytes, escape of red cells through gaps between the endothelial cells DIAPEDESIS, takes place. It is a passive phenomenon - RBC's begin forced out either by raised hydrostatic pressure or may escape through the endothelial defects left after the emigration of leucocytes. Diapedesis gives the hemorrhagic appearance to inflammatory-exudate (Transmigration across the endothelium (also called diapedesis)* The sequence of events in the journey of leukocytes from the vessel lumen to the interstitial tissue called extravasation