Lecture Topic 10: Haematology III

White blood cells

What are WBC also known as?

Leukocytes

Do WBC have a nucleus?

yes

What are the roles of WBC?

Defence against pathogens / remove toxin & waste / remove damaged cells

What is extravasation?

Migrate out of the bloodstream 

What is another word for extravasation?

Diapedesis

What is another word for diapedesis?

Extravasation

What is the word for when a WBC can migrate out of the bloodstream?

Extravasation / Diapedesis

What are the characteristics of WBC?

Migrate out of bloodstream/ capable of amoeboid movement / attracted to specific chemical stimuli 

Which WBC has perform phagocytosis?

Neutrophils / eosinophils / monocytes

Which WBCs are granulocytes?

Neutrophils / eosinophils / basophils

Which WBCs are agranulocytes?

Lymphocytes / monocytes

Which is the most common WBC?

Neutrophils

What is the structure of neutrophils?

9-15um diameter / distinctive nucleus / 2-5 lobes / granular cytoplasm

What are the functions of neutrophils?

First line defence / phagocytic / mobile / circular for ~10hrs / major constituent of pus

What is the percentage of WBC are neutrophils?

50-70%

Which WBC is this?

Neutrophils 

What % of WBC are eosinophils?

2-4%

What is the structure eosinophils?

10-12um diameter / bilobular nucleus

How long do eosinophils circulate in the blood for?

8-12hrs

After circulating for 8-12hrs, what happens to the eosinophils?

Migrate to tissue, surviving 1-3 days

What toxic compounds do eosinophils release?

NO and cytotoxic enzymes

What is the structure of the nucleus in basophils?

Bilobed S shaped nucleus

What granules do basophils have?

Histamine / heparin

What is the diameter of basophils?

8-10um

Which WBC is the least common?

Basophil

What are the functions of basophils?

Inflammatory response / precursor to mast cells 

What do basophil and mast cells share?

A common bone marrow precursor 

What is the lifespan of basophils?

Unknown

What are the physical structures of granules within basophils?

large cytoplasmic granules

Which WBC is the largest in size?

Monocytes

What % of WBC are monocytes?

2-10%

What is the shape of the nucleus in monocytes?

Large kidney / horse shoe shaped nucleus

At what point do monocytes migrate out of circulation?

After 3-4 days

What is the main function of lymphocyte?

Central role in all immunological defence mechanism

What is the lifespan of lymphocytes?

Weeks to several years

What are the main types of lymphocytes?

T cells / B cells / NK cells

What do T cells do?

Mediate cell-mediated immunity

What do B cells do?

Differentiate into plasma cells / secrete antibodies (humoral immunity)

What do NK cells do?

Immune surveillance / important in preventing cancer

What is the order, from most common to least common, of WBCs

Neutrophils / lymphocytes / monocytes / eosinophils / basophils