Monoblasts are normally found in bone marrow and do not appear in the normal peripheral blood. They mature into monocyte

Monocyte

Monocytes are a type of white blood cell and are part of the innate immune system of vertebrates including all mammals , birds, reptiles, and fish. Monocytes play multiple roles in immune function...

s which, in turn, develop into macrophages.

Structure

A typical monoblast is about 12 to 20 µm in diameter, has a nuclear to cytoplasm ratio of 4:1 to 3:1, and, like most myeloid blasts, has a round to oval nucleus with fine chromatin structure. One to four nucleoli are usually visible. The nucleus can be central or eccentric and it can show evidence of indentation or folding. The cytoplasm is agranular, stains moderately to lightly basophilic, and often has an intensely stained periphery and a prominent perinuclear zone.

Maturation

The monoblast is the first stage of monocyte-macrophage maturation. The developmental stages of the monoblast are:
CFU-GM (pluripotential hemopoietic stem cell

Pluripotential hemopoietic stem cell

Hematopoietic stem cells , also spelled Hæmatopoietic stem cells, are multipotent stem cells that give rise to all the blood cell types from the myeloid , and lymphoid lineages...

 or hemocytoblast) -> monoblast -> promonocyte

Promonocyte

A promonocyte is a cell arising from a monoblast and developing into a monocyte.-External links:* * - "Bone marrow smear"*...

 -> monocyte

Monocyte

Monocytes are a type of white blood cell and are part of the innate immune system of vertebrates including all mammals , birds, reptiles, and fish. Monocytes play multiple roles in immune function...

-> macrophage

Macrophage

Macrophages are cells produced by the differentiation of monocytes in tissues. Human macrophages are about in diameter. Monocytes and macrophages are phagocytes. Macrophages function in both non-specific defense as well as help initiate specific defense mechanisms of vertebrate animals...

.

See also

• Monocyte
  Monocyte
  Monocytes are a type of white blood cell and are part of the innate immune system of vertebrates including all mammals , birds, reptiles, and fish. Monocytes play multiple roles in immune function...
  
  
• Macrophage
  Macrophage
  Macrophages are cells produced by the differentiation of monocytes in tissues. Human macrophages are about in diameter. Monocytes and macrophages are phagocytes. Macrophages function in both non-specific defense as well as help initiate specific defense mechanisms of vertebrate animals...
  
  
• Agranulocyte
  Agranulocyte
  Agranulocytes are a category of white blood cells characterised by the absence of granules in their cytoplasm.There are two types of agranulocytes:* Lymphocytes* Monocytes....
  
  
• White blood cell
  White blood cell
  White blood cells, or leukocytes , are cells of the immune system involved in defending the body against both infectious disease and foreign materials. Five different and diverse types of leukocytes exist, but they are all produced and derived from a multipotent cell in the bone marrow known as a...