Human Blood Cell Characteristics

Leucocytes

• Non-granular leucocytes contain specific and non-specific granules.

Monocytes

• Have eccentric and kidney-shaped nucleus.
• Have large, eccentric, bi-lobed, pale nucleus with clear nucleolus.

Null-lymphocytes

• Can kill some cancer cells by a natural immune response.

Eosinophils

• Have functional correlation with basophils and plasma cells.
• Increase in number during treatment with cortisone.
• Attracted to terminate allergic reaction by Eosinophil chemotactic factor (ECF).

Neutrophils

• Secrete collagenase enzyme to help its migration in connective tissue.
• Granules contain phagocytin (Bactericidal), lactoferrin (Bacteriostatic), and histamine.

Lymphocytes

• Not the largest nucleated blood cells.
• Can differentiate into plasma cells during immune responses.
• Percentage in the blood is 30-40%.
• Diameter of a small lymphocyte is 6-9 μm.
• B-lymphocytes are not developed in the spleen.
• T-lymphocytes acquire surface receptors in the thymus.

Basophils

• Nucleus is irregular in shape (mostly S-shaped).
• Secrete histaminases and sulphatase to destroy histamine and heparin.
• Basophilia occurs in liver cirrhosis.

Natural Killer Cells

• Have non-T, non-B receptors and can kill virally infected cells directly by a natural immune response.

Immune Response

• T-Lymphocytes help and activate B-Lymphocytes.
• Helper T Cells secrete perforins that produce pores in the membrane of the foreign cell leading to its lysis.

Clinical Conditions

• Lymphocytosis is caused by acute infections.
• Hemorrhagic anemia is due to excessive destruction of RBCs due to abnormal shape or abnormal Hb content.
• Anaphylactic shock is caused by severe allergy, leading to generalized vasodilation and a severe drop in blood pressure.
• Lymphocytic Leukemia is a type of cancer of the blood characterized by an abnormal decrease of lymphocytes.
• Pus produces Pyrogens which elevate body temperature (fever) to inhibit bacterial growth.