A myelocyte is a young cell of the granulocytic series, occurring normally in

bone marrow Bone marrow is a semi-solid biological tissue, tissue found within the Spongy bone, 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 i ...

(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 cir ...

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. ...

is distinctly basophilic and relatively more abundant than in myeloblasts or promyelocytes, even though myelocytes are smaller cells. Numerous cytoplasmic granules are present in the more mature forms of myelocytes. Neutrophilic and eosinophilic granules are peroxidase-positive, while basophilic granules are not. The nuclear

chromatin Chromatin is a complex of DNA and protein found in eukaryote, 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 ...

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.)

Measurement

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

Development

Promyelocyte --> Myelocytes --> metamyelocytes.

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