Lymphocytes

Lymphocytes are small, round or slightly indented cells with a relatively high nuclear-to-cytoplasmic ratio. They have a large, spherical nucleus. This nucleus occupies most of the cell’s volume. It gives them a “round” appearance under the microscope. The nucleus of lymphocytes is typically dark-staining and may have a smooth or slightly irregular contour.

Nucleus

The nucleus of lymphocytes is typically round or slightly indented and occupies a large portion of the cell’s volume. 

Cytoplasm

Lymphocytes and monocytes are agranulocytes with no granules evident in the cytoplasmThe gel-like substance within a cell that contains organelles and cytosol..  Because of the nucleus that almost fills the cell, lymphocytes have a ring of cytoplasm surrounding the nucleus. .

Function

Lymphocytes such as T cells, B cells, and NK cells each have unique contributions to the immune response. T cells are involved in cell-mediated immunity. B cells are responsible for antibody production. NK cells detect and eliminate infected or abnormal cells.

T cells are characterized by the presence of a round or slightly indented nucleus with dense chromatinDNA and associated proteins in a loose, uncondensed form inside the nucleus.. They typically lack cytoplasmic granules. They are involved in cell-mediated immunity. This includes the recognition and elimination of infected or abnormal cells.

B cells have a round nucleus with less densely packed chromatin compared to T cells. They may contain cytoplasmic vacuoles or vesicles called “”cytoplasmic vesicles”” or “”cytoplasmic droplets.”” B cells are involved in antibody-mediated immunity. They include the production of antibodies (immunoglobulins(Ig) Antibodies: Proteins produced by the immune system to target specific antigens.) and the recognition of pathogens and foreign antigensMolecules on the surface of cells that trigger an immune response..

NK cells have a large, granular nucleus with dispersed chromatin and prominent nucleoli. They contain cytoplasmic granules filled with cytotoxic moleculesGroups of atoms bonded together.. These include perforin and granzymes. These molecules are involved in killing infected or abnormal cells.

Confused With

Lymphocytes can be easily confused with monocytes, another agranulocyte without granules in the cytoplasm.  However, monocytes have a reliably deepAway from the surface of the body. indentation compared to lymphocytes.