Granulocyte

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Granulocyte

Granulocytes are a category of white blood cell

White blood cell

White blood cells , or leukocytes , are cell of the immune system defending the body against both infectious disease and foreign materials....
s characterised by the presence of granule

Granule (cell biology)

In Cell , a granule can be any structure barely visible by light microscopy. The term is most often used to describe a Secretory_pathway Vesicle ....
s in their cytoplasm

Cytoplasm

The cytoplasm is the part of a Cell that is enclosed within the plasma membrane. In eukaryote cells the cytoplasm contains organelles, such as mitochondrion, that are filled with liquid kept separate from the rest of the cytoplasm by biological membranes....
. They are also called polymorphonuclear leukocytes (PMN or PML) because of the varying shapes of the nucleus

Cell nucleus

In cell biology, the nucleus , also sometimes referred to as the "control center", is a membrane-enclosed organelle found in all eukaryote cell ....
, which is usually lobed into three segments.

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Encyclopedia

Granulocytes are a category of white blood cell

White blood cell

White blood cells , or leukocytes , are cell of the immune system defending the body against both infectious disease and foreign materials....
s characterised by the presence of granule

Granule (cell biology)

In Cell , a granule can be any structure barely visible by light microscopy. The term is most often used to describe a Secretory_pathway Vesicle ....
s in their cytoplasm

Cytoplasm

Cell nucleus

In cell biology, the nucleus , also sometimes referred to as the "control center", is a membrane-enclosed organelle found in all eukaryote cell ....
, which is usually lobed into three segments. In common parlance, the term polymorphonuclear leukocyte often refers specifically to neutrophil granulocyte

Neutrophil granulocyte

Neutrophil granulocytes, generally referred to as neutrophils, are the most abundant type of white blood cells in humans and form an essential part of the immune system....
s, the most abundant of the granulocytes. Granulocytes or PMN are released from the bone marrow by the regulatory complement

Complement system

The complement system is a biochemical cascade that helps clear pathogens from an organism. It is part of the larger immune system that is not adaptable and does not change over the course of an individual's lifetime; as such it belongs to the innate immunity....
proteins.

Classification

There are three types of granulocytes, distinguished by their appearance under Wright's stain

Wright's stain

Wright's stain is a histologic stain that facilitates the differentiation of blood cell types. It is used primarily to stain peripheral blood smears and bone marrow needle aspiration biopsy which are examined under a light microscope....
:

Neutrophil granulocyte
Neutrophil granulocyte

Neutrophil granulocytes, generally referred to as neutrophils, are the most abundant type of white blood cells in humans and form an essential part of the immune system....
s
Eosinophil granulocyte
Eosinophil granulocyte

Eosinophil granulocytes, usually called eosinophils , are white blood cells that are one of the immune system components responsible for combating infection and parasites in vertebrates....
s
Basophil granulocyte
Basophil granulocyte

Basophils are the least common of the granulocytes, representing about 0.01% to 0.3% of circulating leukocytes .The name comes from the fact that these leucocytes are basophilic, i.e., they are susceptible to staining by base dyes, as shown in the picture....
s

Their names are derived from their staining

Staining (biology)

Staining is an auxiliary technique used in microscopy to enhance contrast in the microscopic image.In biochemistry it involves adding a class-specific dye to a substrate to qualify or quantify the presence of a specific compound....
characteristics; for example, the most abundant granulocyte is the neutrophil granulocyte

Neutrophil granulocyte

Cytoplasm

The cytoplasm is the part of a Cell that is enclosed within the plasma membrane. In eukaryote cells the cytoplasm contains organelles, such as mitochondrion, that are filled with liquid kept separate from the rest of the cytoplasm by biological membranes....
ic granules.

Other white blood cells which are not granulocytes ("agranulocyte

Agranulocyte

Agranulocytes are a category of white blood cells characterised by the absence of Granule s in their cytoplasm.There are two types of agranulocytes:...
s") are mainly lymphocyte

Lymphocyte

A lymphocyte is a type of white blood cell in the vertebrate immune system.By their appearance under the light microscope, there are two broad categories of lymphocytes, namely the large granular lymphocytes and the small lymphocytes....
s and monocyte

Monocyte

Monocyte is a type of leukocyte, part of the human body's immune system. Monocytes have two main functions in the immune system: replenish resident macrophages and dendritic cells under normal states, and in response to inflammation signals, monocytes can move quickly to sites of infection in the tissues and divide/differentiate into mac...
s.

Toxic materials produced or released

Examples of toxic materials produced or released by degranulation

Degranulation

Degranulation is a cellular process that releases antimicrobial cytotoxic molecules from secretion vesicle s called Granule found inside some cells....
by granulocytes on the ingestion of microorganism includes:

Low pH vesicles
Vesicle (biology)

A vesicle is a small bubble of liquid within a cell. More technically, a vesicle is a small, intracellular, membrane-enclosed sac that stores or transports substances within a cell....
(3.5-4.0)
Toxic oxygen
Oxygen

Oxygen no O2 produced; 2) O2 produced, but absorbed in oceans & seabed rock; 3) O2 starts to gas out of the oceans, but is absorbed by land surfaces and formation of ozone layer; 4-5) O2 sinks filled and the gas accumulates]]...
-derived products (e.g. superoxide
Superoxide

Superoxide is the anion O2−. It is important as the product of the one-electron reduction of dioxygen, which occurs widely in nature....
, hydrogen peroxide
Hydrogen peroxide

Hydrogen peroxide is a very pale blue liquid which appears colorless in a dilute solution, slightly more viscous than water. It is a weak acid....
, hydroxy
Hydroxy

'Hydroxy' can refer to:* In chemical nomenclature, the prefix "hydroxy-" shows the presence of a hydroxyl functional group * An abbreviation for the medication hydroxyzine, which is commonly sold under the brand names Atarax, Ucerax, Serecid, and Vistaril....
radicals, singlet oxygen, hypohalite)
Toxic nitrogen
Nitrogen

Nitrogen is a chemical element that has the symbol N and atomic number 7 and atomic mass 14.00674?. Elemental nitrogen is a colorless, odorless, tasteless and mostly inert diatomic gas at standard conditions, constituting 78% by volume of Earth's atmosphere....
oxides (nitric oxide
Nitric oxide

Nitric oxide or nitrogen monoxide is a chemical compound with chemical formula NitrogenOxygen. This gas is an important signaling molecule in the body of mammals, including humans, and is an extremely important intermediate in the chemical industry....
)
Antimicrobial
Antimicrobial

An antimicrobial is a substance that kills or inhibits the growth of microbes such as bacteria, fungi, protozoals or viruses. Antimicrobial drugs either kill microbes or prevent the growth of microbes ....
agents (Defensin
Defensin

File:Monomeric and dimeric representations of HBD-2.jpgDefensins are small cysteine-rich cationic proteins found in both vertebrates and invertebrates....
s and cationic proteins)
Enzyme
Enzyme

Enzymes are biomolecules that catalysis chemical reactions. Almost all enzymes are proteins. In enzymatic reactions, the molecules at the beginning of the process are called Substrate , and the enzyme converts them into different molecules, the products....
s

Lysozyme
Lysozyme

Lysozymes, also known as muramidase or N-acetylmuramide glycanhydrolase, are a family of enzymes which damage bacterial cell walls by catalyzing hydrolysis of 1,4-beta-linkages between N-acetylmuramic acid and N-acetyl-D-glucosamine residues in a peptidoglycan and between N-acetyl-D-glucosamine residues in chitodextrins....
: dissolves cell walls of some gram positive bacteria
Acid hydrolase
Acid hydrolase

An acid hydrolase is an enzyme that works best at acidic pHs. It is commonly located in lysosomes, which have an acidic milieu. Acid hydrolases may be nucleases, proteases, glycosidases, lipases, phosphatases, sulfatases and phospholipases and make up the approximately 50 degredative enzymes of the lysosome that break apart biological matter...
s: further digest bacteria

Pathology

Granulocytopenia is an abnormally low concentration of granulocytes in the blood. This condition reduces the body's resistance to many infections. Closely-related terms include agranulocytosis

Agranulocytosis

Agranulocytosis is an acute condition involving a severe and dangerous leukopenia particularly of neutrophils causing a neutropenia in the circulating blood....
(no granulocytes at all) and neutropenia

Neutropenia

Neutropenia , from Latin language prefix neutro- and Greek language suffix -pe??a is a Hematology disorder characterized by an abnormally low number of a type of white blood cell called a neutrophil....
(deficiency of neutrophil granulocyte

Neutrophil granulocyte

Neutrophil granulocytes, generally referred to as neutrophils, are the most abundant type of white blood cells in humans and form an essential part of the immune system....
s). Transfusion

Blood transfusion

Blood transfusion is the process of transferring blood or blood-based products from one person into the circulatory system of another. Blood transfusions can be life-saving in some situations, such as massive blood loss due to Physical trauma, or can be used to replace blood lost during surgery....
of granulocytes would have been a solution to the problem. However, granulocytes live only ~10 hours in the circulation (for days in spleen

Spleen

The spleen is an organ found in all vertebrate animals. In humans, the spleen is located in the abdomen of the body, where it functions in the destruction of redundant red blood cells, and holds a reservoir of blood....
or other tissue), which gives a very short-lasting effect. In addition, there are many complications of such procedure.

A granuloma

Granuloma

A granuloma is a medical term for a ball-like collection of immune cells trying to destroy a foreign substance. It represents a special type of inflammatory reaction common to a wide variety of diseases, both infectious and non-infectious....
is a tumor

Tumor

A tumor or tumour is the name for a swelling or lesion formed by an abnormal growth of cells . Tumor is not synonymous with cancer. A tumor can be Benign neoplasm, Carcinoma in situ or malignant, whereas cancer is by definition malignant....
containing granulocytes, and a "granulomatosis" is a necrotizing granuloma.

There is usually a granulocyte chemotactic defect in individuals who suffer from insulin dependent diabetes mellitus.

Granulocyte

Classification

Toxic materials produced or released

Pathology

Additional images

See also

External links