| Cell Type | Count per | Lifespan | Nucleus | Origin | Primary Function | NEET Fact |
|---|---|---|---|---|---|---|
| RBC (Erythrocyte) | 5-5.5M (M); 4.5-5M (F) | 120 days | Absent (anucleate) | Red bone marrow | /C transport via Hb | Destroyed in spleen |
| Neutrophil | 3000-6000 (60-65%) | 5-90 hours | Multi-lobed (polymorphic) | Bone marrow | Phagocytosis of bacteria | Most abundant WBC |
| Eosinophil | 150-450 (2-3%) | 8-12 days (tissue) | Bi-lobed | Bone marrow | Anti-parasitic; allergic response | Elevated in allergy/parasites |
| Basophil | 20-50 (0.5-1%) | Hours to days | S-shaped | Bone marrow | Release histamine + heparin | Least abundant WBC |
| Lymphocyte | 1500-2500 (20-25%) | Years (memory cells) | Large, round | Bone marrow; thymus (T) | B: antibody production; T: cell-mediated | 2nd most abundant WBC |
| Monocyte | 200-800 (6-8%) | Months (as macrophage) | Kidney-shaped | Bone marrow | Phagocytosis; antigen presentation | Differentiates into macrophage in tissue |
| Platelet (Thrombocyte) | 1.5-3.5 lakh | 5-9 days | Absent (cell fragment) | Megakaryocytes (bone marrow) | Blood clotting initiation | Not a true cell — cell fragment |
Memory tip: WBC abundance order = Never (N) Let (L) Monkeys (M) Eat (E) Bananas (B) = Neutrophils > Lymphocytes > Monocytes > Eosinophils > Basophils