[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Physiology](https://durgical.com/en/physiology/) › [Blood, hemostasis and basic immunity](https://durgical.com/en/physiology/#s-blood) › White blood cells: types and functions

[Physiology](https://durgical.com/en/physiology/) · [Blood, hemostasis and basic immunity](https://durgical.com/en/physiology/#s-blood)

# White blood cells: types and functions

- Table to know
- Exam priority: medium

White blood cells are the body's defence team. Each type has a job: eat bacteria, fight parasites, make antibodies or kill infected cells.

Updated 2026-11-01

Also called: Leukocytes, White cell differential

**See it in 3D:** [Spleen](https://durgical.com/en/anatomy/spleen/) · [Thymus](https://durgical.com/en/anatomy/thymus/) · [Hip bone](https://durgical.com/en/anatomy/hip-bone/)

## Key points

- Normal total ≈4 500–11 000/µL; neutrophils are the most numerous, then lymphocytes.
- Neutrophils live only hours in blood and a few days in tissue; bands (immature forms) rising = 'left shift' of bacterial infection.
- Leaving the vessel: rolling (selectins) → firm adhesion (integrins with ICAM-1) → diapedesis → chemotaxis (C5a, IL-8, leukotriene B₄).
- Eosinophils: parasites and allergy; basophils and mast cells: histamine and IgE-mediated reactions.
- Glucocorticoids raise neutrophils (they detach from vessel walls) and lower eosinophils and lymphocytes.

## What it is

Leukocytes are nucleated blood cells that defend tissues; the blood is mainly their highway. They are counted in the complete blood count and sorted in the differential. Granulocytes (neutrophils, eosinophils, basophils) and monocytes are innate cells; lymphocytes carry out adaptive immunity.

## Reference values (adults)

| Parameter | Value | Note |
| --- | --- | --- |
| Total leukocytes | ≈4 500–11 000/µL | |
| Absolute neutrophils | ≈1 500–7 500/µL |

| Cell | Share of white cells | Main job | Rises in |
| --- | --- | --- | --- |
| [Neutrophil](https://durgical.com/en/conditions/sepsis-and-septic-shock/) | ≈40–70 % | Phagocytosis and killing of bacteria and fungi | Bacterial infection, stress, glucocorticoids |
| [Lymphocyte](https://durgical.com/en/conditions/hiv-infection-and-aids/) | ≈20–40 % | Adaptive immunity: B (antibodies), T (helper, cytotoxic), NK | Viral infection, pertussis, chronic lymphocytic leukemia |
| Monocyte | ≈2–8 % | Becomes macrophage or dendritic cell; presents antigen | Chronic infection (tuberculosis), recovery phase |
| Eosinophil | ≈1–4 % | Attacks parasites; modulates allergy | Helminths, asthma and allergy, adrenal insufficiency |
| Basophil | ≈0.5–1 % | Releases histamine and heparin | Allergy, chronic myeloid leukemia |

## Clinical notes

- Dengue typically causes leukopenia with thrombocytopenia, a useful early clue in Colombia.
- HIV destroys CD4⁺ helper T cells; the CD4 count falls while the total white count may look ordinary.
- Leukocyte adhesion deficiency (integrin defect): high blood neutrophils, no pus, delayed separation of the umbilical cord.

## Memory aid

'Never Let Monkeys Eat Bananas' gives the order from most to least common: neutrophils, lymphocytes, monocytes, eosinophils, basophils.

## Test yourself

Think of the answer, then tap the question to see it.

## Why does a patient given glucocorticoids show a high neutrophil count without infection?

Glucocorticoids reduce adhesion molecules, so neutrophils in the marginated pool detach from vessel walls into the circulating pool, and marrow release rises; it is a redistribution, not an infection.

## What does a 'left shift' mean on a differential count?

More immature neutrophils (bands, sometimes metamyelocytes) in blood, because the marrow releases cells early under strong demand, typically bacterial infection or sepsis.

## A child has high blood neutrophils, recurrent infections without pus and delayed umbilical cord separation. Which step of leukocyte migration fails?

Firm adhesion: β2-integrins (CD18) cannot bind ICAM-1, so neutrophils roll but never leave the vessel to reach the tissue.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/physiology/white-blood-cells-types-and-functions/)

## See it in 3D

The structures of Durgical's 3D anatomy where it happens.

- [Spleen](https://durgical.com/en/anatomy/spleen/)
- [Thymus](https://durgical.com/en/anatomy/thymus/)
- [Hip bone](https://durgical.com/en/anatomy/hip-bone/)

## Related topics

- [The physiology of inflammation](https://durgical.com/en/physiology/the-physiology-of-inflammation/)
- [Innate and adaptive immunity: overview](https://durgical.com/en/physiology/innate-and-adaptive-immunity-overview/)
- [Hematopoiesis](https://durgical.com/en/physiology/hematopoiesis/)

## Related conditions

- [Sepsis and septic shock](https://durgical.com/en/conditions/sepsis-and-septic-shock/)
- [HIV infection and AIDS](https://durgical.com/en/conditions/hiv-infection-and-aids/)
- [Dengue](https://durgical.com/en/conditions/dengue/)

[← All of physiology](https://durgical.com/en/physiology/)

Educational physiology content; not a diagnostic or treatment guide and no substitute for a health professional's advice. Values are approximate references. No doses are given.

Sources: [18.4 Leukocytes and Platelets](https://openstax.org/books/anatomy-and-physiology-2e/pages/18-4-leukocytes-and-platelets) (OpenStax (Rice University), 2022); [Complete Blood Count (CBC)](https://medlineplus.gov/lab-tests/complete-blood-count-cbc/) (MedlinePlus (U.S. National Library of Medicine), 2024); Hall JE. Guyton and Hall Textbook of Medical Physiology, 13th ed. (ch. 34). Reference book used to check facts; its text and figures are not reproduced (Elsevier, 2016).

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Representative model, for educational purposes only.

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