Physiology · Blood

WBC classification, functions and leukocyte physiology

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Definition

  • Leucocytes (white blood cells) are nucleated blood cells providing the body's defence functions; classified as granulocytes (neutrophils, eosinophils, basophils) and agranulocytes (lymphocytes, monocytes).

Total leucocyte count4,000 to 11,000 per mm³ of blood

Classification and Normal Counts

Types of leucocytes and their normal distribution

Type

Neutrophils

DLC (%)
50 to 70
Absolute count (per cu mm)
2000 to 2750

Eosinophils

DLC (%)
2 to 4
Absolute count (per cu mm)
40 to 440

Basophils

DLC (%)
0 to 1
Absolute count (per cu mm)
20 to 80

Lymphocytes

DLC (%)
20 to 40
Absolute count (per cu mm)
500 to 8000

Monocytes

DLC (%)
2 to 8
Absolute count (per cu mm)
~400 (average)
  • After a short circulating life, leucocytes enter tissues; there monocytes transform into macrophages, a component of the mononuclear phagocyte system.

Leucopoiesis

Leucopoiesis Branch