6. WBC Morphology

Presentation focuses on the morphology of white blood cells, particularly related to hematopoiesis (the process of blood cell formation).

Hematopoiesis: The process of blood cell production and maturation that occurs in the bone marrow.

Progenitor Cells
- Common Lymphoid Progenitor
- Further differentiates into lymphocytes including lymphoblasts and mature lymphocytes.
- Common Myeloid Progenitor
- Gives rise to various myeloid cells including erythrocytes, granulocytes, monocytes, and thrombocytes.

Stages of Development
- Lymphoblast
- Prolymphocyte
- Large Lymphocyte
- Small Lymphocyte
Cell Types and Their Descriptions
- Small Lymphocyte
- Diameter: 8-12 µm
- N:C Ratio: High
- Nucleus: Round with coarse dense chromatin
- Cytoplasm: Weakly basophilic and clear without inclusions
- Function: Major role in immune response, especially viral infections.
- Large Lymphocyte
- Diameter: 12-16 µm
- Nucleus: Irregular shape, less coarse chromatin than small lymphocytes
- Cytoplasm: Abundant and light blue
- Function: Important in immune response.

Stages of Development
- Myeloblast
- Promyelocyte
- Myelocyte
- Metamyelocyte
- Band Neutrophil
- Segmented Neutrophil
Descriptions of Myeloid Cells
- Myeloblast
- Diameter: 12-20 µm
- Nucleus: Large, round or oval; fine chromatin with 1-2 nucleoli
- Cytoplasm: Basophilic; granules may be absent.
- Significance: Found in bone marrow, can indicate disease if present in blood (e.g., Acute Myeloid Leukemia).
- Promyelocyte
- Diameter: 15-25 µm
- Nucleus: Oval/round shape, prominent nucleolus, fine chromatin
- Cytoplasm: Basophilic with red-violet primary granules.
- Myelocyte
- Diameter: 10-18 µm; round/oval nucleus, not as large as myeloblast
- Cytoplasm: Blue-pink with red-violet granules; characteristics develop as cell matures.
- Metamyelocyte
- Smaller than myelocyte with indented nucleus.
- Function: Usually present in the marrow but can be seen in peripheral blood during infection or specific syndromes.
- Band Neutrophil
- Diameter: 10-14 µm; band-shaped nucleus.
- Cytoplasm: Abundant pink with violet-pink granules.
- Role: Primary function is phagocytosis in infection or inflammation.
- Segmented Neutrophil
- Similar in size to Band neutrophils; nucleus is segmented usually into 3-4 lobes.
- Cytoplasm: Abundant with pink granules; major function is as tissue phagocytes.

Stages of Development
- Monoblast
- Promonocyte
- Monocyte
Monocyte Description
- Diameter: 15-22 µm; largest blood cell.
- Nucleus: Irregular, kidney-shaped; fine strands of chromatin.
- Cytoplasm: Light blue-grey, dust-like granules, possible vacuolization.
- Function: Differentiate into macrophages in tissues, play a role in defense against pathogens.

Stages of Development
- Proerythroblast
- Basophilic Erythroblast
- Polychromatic Erythroblast
- Orthochromatic Erythroblast
- Reticulocyte (immature erythrocyte)
- Erythrocyte (mature red blood cell)
Erythroblast Description
- Nucleated red blood cells appear in peripheral circulation; these cells are crucial in assessing various blood conditions.

Stages of Development
- Megakaryocyte
- Thrombocyte
Thrombocyte (Platelet) Description
- Diameter: 1.5-3 µm; round or oval in EDTA-anticoagulated blood.
- Function: Key role in coagulation process, crucial for wound healing and maintaining hemostasis.

Key Classification Challenges
- The presentation lists key challenges in classifying blood cells, although specifics on these challenges were not detailed in the transcript.

Each cell type's visual characteristics through the Wright-Giemsa stain are detailed, essential for laboratory identification.