GENERAL HISTOLOGY

Detailed explanation-1: -Immune cells, such as macrophages and activated T cells, release substances that attract other immune cells to the trouble spot, thus mobilizing defenses. The invader itself may release substances that attract immune cells.

Detailed explanation-2: -Macrophages interact with T cells in order to bring about T cell activation in target organs, and are themselves activated by inflammatory messenger molecules (cytokines) produced by the T cells. Macrophages produce toxic chemicals, such as nitric oxide, that can kill surrounding cells.

Detailed explanation-3: -Macrophages are essential for wound healing. They replace polymorphonuclear neutrophils as the predominant cells in the wound by day two after injury. Attracted to the wound site by growth factors released by platelets and other cells, monocytes from the bloodstream enter the area through blood vessel walls.

Detailed explanation-4: -Additionally, macrophages release chemokines, leukotrienes, prostaglandins, and complement. All of these molecules, in concert, may induce increased vascular permeability and recruitment of inflammatory cells.