Neutrophil

Detailed information about neutrophils

Neutrophil

A neutrophil with a multi-lobed nucleus

Cell information
System	Immune system
Function	Phagocytosis of bacteria and fungi
Location	Blood
Origin
Precursor
Gives rise to

Neutrophils are a type of white blood cell that play a crucial role in the immune system. They are the most abundant type of granulocyte and form an essential part of the innate immune system. Neutrophils are primarily involved in the defense against bacterial and fungal infections.

Structure

Neutrophils are characterized by their multi-lobed nucleus, which typically consists of three to five lobes connected by thin strands of chromatin. This unique structure allows them to move more easily through the walls of blood vessels and into the tissues where they are needed.

Function

The primary function of neutrophils is to perform phagocytosis, a process by which they engulf and digest microorganisms and cellular debris. Neutrophils are also involved in the release of cytokines and chemokines, which help to recruit other immune cells to the site of infection.

Phagocytosis

During phagocytosis, neutrophils recognize and bind to pathogens using specific receptors. Once bound, they engulf the pathogen in a process that involves the formation of a phagosome. The phagosome then fuses with lysosomes to form a phagolysosome, where the pathogen is destroyed by enzymes and reactive oxygen species.

Degranulation

Neutrophils contain granules filled with antimicrobial substances. Upon activation, they can release these substances into the extracellular space in a process known as degranulation. This helps to kill pathogens and modulate the immune response.

Neutrophil Extracellular Traps (NETs)

Neutrophils can also form neutrophil extracellular traps (NETs), which are networks of extracellular fibers composed of DNA and antimicrobial proteins. NETs trap and kill pathogens, preventing their spread.

Clinical significance

Neutrophils are a key component of the complete blood count (CBC) test, and their levels can indicate various medical conditions. An increased number of neutrophils, known as neutrophilia, can be a sign of infection, inflammation, or stress. Conversely, a decreased number of neutrophils, known as neutropenia, can make individuals more susceptible to infections and may be caused by bone marrow disorders, chemotherapy, or autoimmune diseases.

See also

• Leukocyte
• Immune response
• Inflammation