BIOLOGY 2B03 Lecture 8: (Module 8) Neutrophil Extravasation
30 Nov 2016
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Document Summary
Movement of leukocytes out of blood vessel depends upon precise sequence of adhesive interactions (which are together called extravasation) Note: endothelial cells are specialized epithelial cells that form walls of blood vessels. Leukocytes need to be able to establish temporary connections with endothelial cells in order to mediate process of extravasation & get to site of infection. One of first cells to respond to trauma; undergo extravasation. Monocytes: differentiate into macrophages (which engulf invading bacteria or dead & damaged cells through phagocytosis); capable of extravasation. Natural killer (nk) cells: lyse virally infected cells & tumor cells. T & b cells: produce antibodies as part of immune response; Five step process initiated by signal created by an infection. Extravasation begins when a transient association is made between neutrophil & apical surface of endothelial cell (within endothelial wall) (i. e. capturing) Neutrophils are still pushed by flow of blood through vessels, but movement slows as cells roll along surface of endothelial cells.
