Leukocytes

type of cells of the immunological system

thumb|Scanning electron microscope|Scanning electron micrograph of a neutrophil phagocytosing anthrax bacilli (orange)|alt= Long rod-shaped bacteria, one of which has been partially engulfed by a larger blob-shaped white blood cell. The shape of the cell is distorted by undigested bacterium inside it.

Granulocytes are cells in the innate immune system characterized by the presence of specific granules in their cytoplasm. Such granules distinguish them from the various agranulocytes. All myeloblastic granulocytes are polymorphonuclear, that is, they have varying shapes (morphology) of the nucleus (segmented, irregular; often lobed into three segments); and are referred to as polymorphonuclear leukocytes (PMN, PML, or PMNL). In common terms, polymorphonuclear granulocyte refers specifically to "neutrophil granulocytes", the most abundant of the granulocytes; the other types (eosinophils, baso

A megakaryocyte () is a large bone marrow cell with a lobated nucleus that produces blood platelets (thrombocytes), which are necessary for normal clotting. In humans, megakaryocytes usually account for 1 out of 10,000 bone marrow cells, but can increase in number nearly 10-fold during the course of certain diseases. Owing to variations in combining forms and spelling, synonyms include megalokaryocyte and megacaryocyte.

Neutropenia is an abnormally low concentration of neutrophils (a type of white blood cell) in the blood. Neutrophils make up the majority of circulating white blood cells and serve as the primary defense against infections by destroying bacteria, bacterial fragments and immunoglobulin-bound viruses in the blood. People with neutropenia are more susceptible to bacterial infections and, without prompt medical attention, the condition may become life-threatening (neutropenic sepsis).

thumb|250px|Monocyte under a light microscope (40x) from a peripheral blood smear surrounded by [[red blood cells.]]

thumb|108px|Basophilic thumb|108px|Eosinophilic thumb|108px|Neutrophilic

A promyelocyte (or progranulocyte) is a granulocyte precursor, developing from the myeloblast and developing into the myelocyte. Promyelocytes measure 12–20 microns in diameter. The nucleus of a promyelocyte is approximately the same size as a myeloblast but their cytoplasm is much more abundant. They also have less prominent nucleoli than myeloblasts and their chromatin is more coarse and clumped. The cytoplasm is basophilic and contains primary red/purple granules.

69px|thumb|Basophilic 69px|thumb|Eosonophilic 69px|thumb|Neutrophilic A metamyelocyte is a cell undergoing granulopoiesis, derived from a myelocyte, and leading to a band cell.

phase of elevated metabolic activity, during which oxygen consumption increases

tiny bright dots moving quickly in the visual field

cell type

A megakaryoblast () is a precursor cell to a promegakaryocyte. During thrombopoiesis, the promegakaryocyte matures into the form of a megakaryocyte. From the megakaryocyte, platelets are formed. The megakaryoblast is the beginning of the thrombocytic series or platelet forming series.

type of mammalian cell that functions as a component of the innate immune system

Monoblasts are the committed progenitor cells that differentiated from a committed macrophage or dendritic cell precursor (MDP) in the process of hematopoiesis. They are the first developmental stage in the monocyte series leading to a macrophage. Their myeloid cell fate is induced by the concentration of cytokines they are surrounded by during development. These cytokines induce the activation of transcription factors which push completion of the monoblast's myeloid cell fate. Monoblasts are normally found in bone marrow and do not appear in the normal peripheral blood. They mature into monoc

protein-coding gene in the species Homo sapiens

The spleen is the body’s largest blood filter, performing important functions within the lymphatic system and serving as the most important organ for immune function. Splenocytes are important components of this lymphatic system, consisting of all immune cells that reside within the spleen. The biggest difference between splenocytes and immune cells in other lymphatic organs is the fact that the spleen filters blood, not lymph. They are, therefore, able to protect the body from invaders in ways that the lymphatic system cannot.