neutrophil

Examples of neutrophil in the following topics:

• Phagocyte Migration and Phagocytosis

  • Phagocytosis of bacteria by human neutrophils takes on average nine minutes to occur.
  • In the blood, neutrophils are inactive but are swept along at high speed.
  • Another group of chemical attractants are cytokines that recruit neutrophils and monocytes from the blood.
  • Signals from the infection cause the endothelial cells that line the blood vessels to make a protein called selectin, which neutrophils stick to when they pass by.
  • During an infection, millions of neutrophils are recruited from the blood, but they die after a few days.

• WBC Function

  • This process is performed primarily by neutrophils, macrophages, and dendritic cells, but most other leukocytes can do it as well.
  • When a pathogen is detected, or when vascular endothelial cells release stress cytokines from injury (such as a cut) leukocytes will release a variety of inflammatory cytokines (such as histamine or TNF-alpha) that cause vasodilation, increased vascular permeability, and promote neutrophil movement to the site of inflammation.
  • This process is performed by granulocytes like neutrophils.
  • Here, neutrophils can be seen to phagocytose and completely engulf bacteria.

• Types of WBCs

  • The different types of white blood cells (leukocytes) include neutrophils, basophils, eosinophils, lymphocytes, monocytes, and macrophages.
  • All categories except neutrophils contain IgE receptors that implicate them in allergic responses.
  • Neutrophils defend against bacterial or fungal infection and other very small inflammatory processes.
  • They typically arrive at the site of inflammation one to three days after the initial neutrophil response to clean up dead neutrophils, cellular debris, and remaining pathogens.
  • From left to right, a neutrophil, an eosinophil, and a basophil.

• Phagocytes

  • The main types of phagocytes are monocytes, macrophages, neutrophils, tissue dendritic cells, and mast cells.
  • During inflammation, they enter about 72 hours after the initial response to clean up debris and dead neutrophils.
  • Neutrophils are a type of PMN granulocyte normally found in the bloodstream.
  • Neutrophils die after phagocytosis, becoming pus that is later cleaned up by macrophages.
  • Monocytes differentiate into dendritic cells and macrophages, while mast cells and neutrophils are in a separate group of PMN granuolcytes as well.

• Macrophages

  • Where a pathogen is involved, they are commonly preceded by neutrophils, which release a range of toxic agents designed to kill extracellular pathogens.
  • The macrophage then has the task of clearing both the dead pathogens and the dead neutrophils.
  • The process of recruitment of neutrophils and macrophages involves the resident macrophages which act as sentinels.

• Pathogen Recognition

  • A neutrophil is also a phagocytic leukocyte that engulfs and digests pathogens .
  • A basophil is a leukocyte that, like a neutrophil, releases chemicals to stimulate the inflammatory response .
  • Neutrophils and monocytes leave the capillaries.
  • Neutrophils, dendritic cells, and macrophages release chemicals to stimulate the inflammatory response.
  • Neutrophils and macrophages also consume invading bacteria by phagocytosis.

• Inflammation

  • The next step of the acute inflammatory response is chemotaxis migration of neutrophils to the affected area.
  • Neutrophils are recruited to the site of inflammation by various cytokines.
  • The neutrophils loosely attach to the endothelial cells through use of selectins, a process called rolling.
  • Then the neutrophils follow a chemotactic gradient to the site of infection of injury in the tissues, where they will degranulate and phagocytize pathogens.
  • Later, macrophages enter the tissues through a similar process to clean up dead neutrophils and cellular debris.

• Innate Immune Response

  • In this compound light micrograph, purple-stained neutrophil (upper left) and eosinophil (lower right) are white blood cells that float among red blood cells in this blood smear.
  • Neutrophils provide an early, rapid, and nonspecific defense against invading pathogens.

• Cells and Organs of the Immune System

  • Neutrophils and macrophages are phagocytes that travel throughout the body in pursuit of invading pathogens.
  • Neutrophils are normally found in the bloodstream and are the most abundant type of phagocyte.
  • Basophils and eosinophils are related to neutrophils.
  • Neutrophil engulfing anthrax bacteria.
  • Red blood cells, several white blood cells including lymphocytes, a monocyte, a neutrophil, and many small disc-shaped platelets.

• Abscesses and Ulcers

  • An abscess is a collection of pus (dead neutrophils) that has accumulated in a cavity formed by the tissue in which the pus resides, due to an infectious process (usually related to bacteria or parasites) or other foreign materials (e.g. splinters, bullet wounds, or injecting needles).
  • An abscess is a collection of pus (dead neutrophils) that has accumulated in a cavity formed by the tissue on the basis of an infectious process (usually caused by bacteria or parasites) or other foreign materials (e.g. splinters, bullet wounds, or injecting needles).