- This is simple diagram of cell structure
Cell Structure
1- Cell size:
Blood cells can be discriminated on the basis of their cell size
2- Overall cell size:
The most immature cells are large in size, as the cell become more and more mature the overall cell size decreases
Cell Size and Maturation
3- Nucleus and its morphological changes
We look for the following things:
- Nucleus to cytoplasm ratio (N/C ratio)
- Nuclear shape
- Nucleolus: size, number
- Nuclear chromatin: coarse or fine
- Nuclear chromatin arrangement
- Nuclear position
- Nuclear lobulation and
- number of lobes
N/C Ratio:
- N/C ratio means the nucleus to cytoplasm ratio.
- Immature cells have higher N/C ratio than mature cells .As cell become more mature its nucleus will be decreased in size and subsequently cytoplasm increase in amount.So when you see a cell with high N/C ratio you become suspicious that it is immature cell, but this is NOT always true as mature lymphocytes have high N/c ratio .
Examples: N/C ratio
N/C Ratio
Nuclear Shape:
- The shape of the nucleus may aid in the identification of a cell.
- From regular round to irregular in shape as the cell matures.
Nuclear Shape
Nucleolus size and their number:
- Nucleolus are found in the most immature cells, so there presence alert us that the cell between our hand is immature.
- Also their number and size may also aid in the identification of cells.
Nuclear position:
- Position of nucleus also may let us be aware of specific cell type.
Nuclear Position
Cytoplasm: we look for
- Cytoplasm color
- Granulation
- Type of granules (primary or secondary)
- Granules cover the nucleus or not??
- Cytoplasmic inclusion bodies
- Rigidity of the cytoplasm
Cytoplasm color:
- Most immature cells will have deep blue cytoplasm as the cells mature the blue color decreases and decreases and may be changed to orange color or to gray color according to the cell type.
Granulation
- All red blood cell precursors are NON granulated.
- The Myeloblasts are nongranulated (but this may deviate in specific situations).
- The granulocyte precursors are granulated from promyelocyte to the most mature segmented forms.
- Lymphocytes and its precursors are nongranulated (but there are some cells that are granulated and these cells are mostly natural killer cells (NK)).
- Most mature megakaryotcytes are granulated.
Type of granulation :
- Granules are present in the cytoplasm of cells.
- Granulation starts from primary granules or also are celled azurophilic granules, or nonspecific granules.
- These granules are dark blue or even will appear as black according to your staining.
- The will appear the specific granules or called secondary granules ( for example: Eosinophil will have orange granules, basophil will have dark blue granules, neutrophils will have pink granules)
Granules cover the nucleus:
- Some cells the granules cover the nucleus such as the promyelocyte (primary granules), basophil (specific granules: dark violet in color and big), mast cells (same as basophil but the granule are more numerous).
Rigidity of the cytoplasm:
- This is used to differentiate between atypical lymphocyte and monocytes and not all times>
- Cells Maturation
