Difference between revisions of "Lymphocytes - Introduction"
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==Introduction== | ==Introduction== | ||
− | Lymphocytes account for around a third of all circulating [[Leukocytes|leukocytes]] and are formed in a variety of lymphoid tissues. They are functionally divided into | + | Lymphocytes account for around a third of all circulating [[Leukocytes|leukocytes]] and are formed in a variety of lymphoid tissues. They are functionally divided into T cells, B cells and NK Natural Killer (NK) cells. Lymphocytes vary in size (6-30µm) and are classified as small, medium or large. Large cells are either activated lymphocytes or NK cells. The vast majority of circulating lymphocytes are small and of a similar size to erythrocytes. Histologically they are round with a large densely staining nucleus and a thin, often indistinct, rim of cytoplasm. While NK cells can be distinguished by their large granules and kidney shaped nucleus, B and T cells appear the same histologically. |
− | <p>Lymphocytes, along with associated supporting cells, form the immune system and recognise antigens, produce antibodies and destroy pathogens.</p> | + | <p>Lymphocytes, along with the associated supporting cells, form the immune system and recognise antigens, produce antibodies and destroy pathogens.</p> |
==Development== | ==Development== |
Revision as of 15:44, 24 September 2010
Introduction
Lymphocytes account for around a third of all circulating leukocytes and are formed in a variety of lymphoid tissues. They are functionally divided into T cells, B cells and NK Natural Killer (NK) cells. Lymphocytes vary in size (6-30µm) and are classified as small, medium or large. Large cells are either activated lymphocytes or NK cells. The vast majority of circulating lymphocytes are small and of a similar size to erythrocytes. Histologically they are round with a large densely staining nucleus and a thin, often indistinct, rim of cytoplasm. While NK cells can be distinguished by their large granules and kidney shaped nucleus, B and T cells appear the same histologically.
Lymphocytes, along with the associated supporting cells, form the immune system and recognise antigens, produce antibodies and destroy pathogens.
Development
Both T and B lymphocytes develop from a common stem cell (CFU-L's) and for a general overview of this process see here.
Follow these links for a more detailed explanation on T cell development and B cell development.