Question

Compare and contrast the 5 different types of leukocytes (both structure and function).

Answer 1

Leukocytes or white blood cells are type of blood cells that take part in immune system.
The five types of leukocytes are :

1. Neutrophils : most abundant type of leukocytes.
They have a diameter of 12–15 micrometers. The cell cytoplasm is granulated and granules appear lilac on the smear film. The nucleus is lobed.
They take part in inflammatory process, release cytokines and acts as phagocytes.

2. Lymphocytes: Lymphocytes have a diameter of about 7um. These are agranulated and contains a single large nucleus. These cells appear purple on blood film.
Lymphocytes differentiate into T cells and B cells which takes part in humoral immunity or cell mediated immunity. B cells release antibodies againdt foreign antigens while T cells mature into cytotoxic T cells that help destroy the pathogen through release of cytotoxic substances.

3. Monocytes : monocytes are the largest leukocytes with a diameter of 16-22um. They are agranulated with a unilobar nucleus. The nucleus is usually horse shor shaped or kidney shaped.
Monocytes take part in innate and adaptive immunity. They can differentiate into dendritic cells and macrophages and functions as phagocytes and antigen presenting cells.
4. basophils : these are densely granulated and granules appear dark purple on stained blood film. They are bilobed.
Basophils take part in inflammatory reaction, specially allergic reaction and release histamine and serotonin. They also secrete hepatin which prevents blood from cloting.

5. Eosinophils: these are granulated leukocytes with cell size of about 12–17um. They have a bilobed nuclei. They appear bright orange on blood film.
They take part in immune response against parasitic infections and other infections. They also take part in allergic reactions and secrete histamine.