Components of Blood

Over the page is an illustration of a histology micrograph of a   human blood smear. I have listed below a brief description of each of the cells functions and their appearances.


Erythrocytes – Red Blood Cells
Erythrocytes make up 55% of our total blood volume. Their function is to transport oxygen from the lungs to all cells in the body. They have NO NUCLEUS. These are the most numerous of the blood cells, and much smaller than the Leucocytes (white blood cells). They live for approx.120 days. They are bio-concave in shape and approx. 6-8µm in size. They contain the pigment Haemoglobin. They are red- dark red in colour.

Leucocytes – White Blood Cells, # 2 - 4

Neutrophil (Granulocyte)
The Neutrophil are the most common Leucocytes at around 65% of WBC (White Blood Count). They are phagocytic, meaning they can ingest other cells, though they do not survive the act. They are high in number and responsible for the bulk of an immune response. The cytoplasm is transparent because its granules are small and faintly pink in colour. You can recognise them as their nucleus is 'multi-lobed' divided into 2-5 lobes connect by a fine nuclear strand. They are 10 -15 µm in size

Eosinophil (Granulocyte)
The Eosinophil are quite rare in the blood, counting for around 1-3% of WBC. They are recognised by their nucleus which has a 'bi-lobed' shape, 2 lobes connected by the nuclear strand. Eosinophil's are involved in the immune system response, they appear to play a role in allergic reactions. The nucleus is purple and the cytoplasm is pink. The are the same size as a Neutrophil around 10-15 µm.

Lymphocyte (Agranulocyte)
Lymphocyte's are quite common in the blood at around 20 – 40% of WBC. They are generally smaller than other Leucocytes, but still mainly larger that Erythrocytes. The Lymphocytes are generated by the immune system to fight infection, they secrete antibodies. The nucleus is round and large, occupying most of the cell, with some...