A myelocyte is a young

cell Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery ...

of the granulocytic series, occurring normally in

bone marrow Bone marrow is a semi-solid tissue found within the spongy (also known as cancellous) portions of bones. In birds and mammals, bone marrow is the primary site of new blood cell production (or haematopoiesis). It is composed of hematopoietic ce ...

(can be found in circulating

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the c ...

when caused by certain diseases).

Structure

When stained with the usual dyes, the

cytoplasm In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. The ...

is distinctly

basophilic Basophilic is a technical term used by pathologists. It describes the appearance of cells, tissues and cellular structures as seen through the microscope after a histological section has been stained with a basic dye. The most common such dye i ...

and relatively more abundant than in myeloblasts or

promyelocyte 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 m ...

s, even though myelocytes are smaller cells. Numerous cytoplasmic granules are present in the more mature forms of myelocytes. Neutrophilic and eosinophilic granules are

peroxidase Peroxidases or peroxide reductases ( EC numberbr>1.11.1.x are a large group of enzymes which play a role in various biological processes. They are named after the fact that they commonly break up peroxides. Functionality Peroxidases typically ca ...

-positive, while basophilic granules are not. The nuclear

chromatin Chromatin is a complex of DNA and protein found in eukaryotic cells. The primary function is to package long DNA molecules into more compact, denser structures. This prevents the strands from becoming tangled and also plays important roles in r ...

is coarser than that observed in a promyelocyte, but it is relatively faintly stained and lacks a well-defined membrane. The nucleus is fairly regular in contour (not indented), and seems to be 'buried' beneath the numerous cytoplasmic granules. (If the nucleus were indented, it would likely be a

metamyelocyte A metamyelocyte is a cell undergoing granulopoiesis, derived from a myelocyte, and leading to a band cell. It is characterized by the appearance of a bent nucleus, cytoplasmic granules, and the absence of visible nucleoli. (If the nucleus is n ...

Measurement

There is an internationally agreed method of counting blasts, with results from M1 upwards.

Development

Promyelocyte 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 m ...

--> Myelocytes -->

Additional images

File:Hematopoiesis (human) diagram en.svg, Hematopoiesis

References

External links

Neutrophilic Myelocyte
Presented by the University of Virginia
Eosinophilic Myelocyte
Presented by the University of Virginia
Basophilic Myelocyte
Presented by the University of Virginia

{{Authority control Leukocytes