What is the Difference Between Promyelocyte and Myelocyte?

The main differences between promyelocytes and myelocytes are related to their size, nucleus shape, chromatin organization, and cytoplasmic granules. Here are the key differences:

1. Size: Promyelocytes are generally larger than myelocytes, with a size ranging from 12 to 25 µm, while myelocytes have a size ranging from 10 to 20 µm.
2. Nucleus Shape: Promyelocytes have round to oval nuclei, while myelocytes have similar nucleus shapes but lack the presence of a nucleolus.
3. Chromatin Organization: In promyelocytes, the chromatin is smooth and uniformly distributed, with no distinct clumps of condensed chromatin. In myelocytes, the chromatin is coarser than that of promyelocytes.
4. Cytoplasmic Granules: Promyelocytes have a blue cytoplasm with numerous azurophilic granules and no specific granulation. Myelocytes, on the other hand, have a cytoplasm that is light blue in color with secondary granules. The granules in myelocytes are mostly pale, specific granules, while promyelocytes have large, dark purple, primary (azurophilic) granules.

In summary, promyelocytes are larger cells with round to oval nuclei, smooth chromatin, and azurophilic granules in their cytoplasm. Myelocytes are smaller cells with round to oval nuclei, coarser chromatin, and a combination of azurophilic and specific granules in their cytoplasm.

Comparative Table: Promyelocyte vs Myelocyte

Here is a table comparing the differences between promyelocytes and myelocytes:

Promyelocytes and myelocytes are both immature white blood cells found in the bone marrow, but they differ in their level of maturity and development. Promyelocytes are larger, have more prominent nucleoli, and have dark purple granules, while myelocytes are smaller, lack nucleoli, and have primarily pale, specific granules.