What are the 4 steps associated with leukocyte extravasation?
The phases of the leukocyte extravasation depicted in the schema are: approach, capture, rolling, activation, binding, strengthening of the binding and spreading, intravascular creeping, paracellular migration or transcellular migration.
Why does leukocyte extravasation occur?
Leukocyte extravasation occurs predominantly in post-capillary venules where hemodynamic shear stress is low. At first, flowing leukocytes decelerate by rolling on the activated endothelium.
What is extravasation process?
Extravasation is the leakage of a fluid out of its container into the surrounding area, especially blood or blood cells from vessels. In the case of inflammation, it refers to the movement of white blood cells from the capillaries to the tissues surrounding them (leukocyte extravasation, also known as diapedesis).
What happens during neutrophil extravasation?
In this process of extravasation, neutrophil undergoes (a) intrusion, (b) perivascular embedment & crawling, (c) protrusion, and then finally (d) uropod elongation & microparticle formation. Microparticles (red dot) are formed in this stage, and usually embedded between endothelial cells and pericytes.
What is the role of leukocytes during inflammation?
The chemicals that trigger an inflammatory response attract leukocytes to the site of injury or infection. Leukocytes are white blood cells. Their role is to fight infections and get rid of debris. Leukocytes may respond with either a nonspecific or a specific defense.
What to do if extravasation occurs?
If extravasation occurs, the injection should be stopped immediately and the IV tubing disconnected. Avoid applying pressure to the site, and do not flush the line. Leave the original catheter in place, and attempt to aspirate as much of the infiltrated drug as possible.
Which three leukocytes can be phagocytic?
In the blood, two types of white blood cells, neutrophilic leukocytes (microphages) and monocytes (macrophages), are phagocytic.
What do selectins do?
The selectins are cell surface lectins that have evolved to mediate the adhesion of white blood cells to endothelial cells and platelets under flow. The selectins are physiologically important in inflammation, lymphocyte homing, immunological responses, and homing of bone marrow stem cells.
