White blood cells

Granulocytes 
Are phagocytes, which have the ability to ingest viruses, bacteria and other parasites. They have visible granules or grains in their cytoplasm and have large elongated or lobed nuclei. The  diameter of cell measures approximately from (12 – 20) μ, and their nucleoli cannot be seen. They account for approximately 60% of our WBCs. The sub-types of granulocytes are: neutrophil, basophil and eosinophil.   
  • Neutrophils  are a part of the innate immune system and an essential line of defense against bacteria. The shape of  nucleus is like a “U” or a curled rod prior to segmentation. They are also known as “band neutrophils”. The diameter usually ranges between (10–18)μ. The cytoplasm is moderate to abundant with a few non-specific granules. Neutrophils account  for  approximately  (1%–3%) of the peripheral WBCs. The diameter of a segmented neutrophil cell  usually ranges between (9–16)μ. They have a multi-lobed nucleus (three or four lobes normally), and these lobes may overlap or twist. The number of lobes can increase according to the cell age. For example a hypersegmented neutrophil cell has seven lobes in mature stage. The intra-cellular granules are visible in the cytoplasm (Giemsa-stained, high magnification). 
  • Basophils secrete anticoagulant substances and antibodies that have the ability to fight against hypersensitivity reactions in the blood stream. They are the smallest circulating granulocytes. The basophilic granules in this cell are large and very numerous, so they often mask the nucleus. The nucleus is often bilobed or unsegmented and it is rarely separated into three or four lobes. The average diameter  ranges between approximately (10–15)μ. 
  • Eosinophils  have the ability to release toxins from their granules for killing pathogens, such as parasites and worms. They are easily recognized in stained smears by their large granules. The nucleus of the eosinophil has often two lobes connected by a band of nuclear material. The diameter usually ranges between (9–15)μ. They account between (1%–4%) of the peripheral WBCs.  
Monocytes 
Stimulate osteoclasts cells, which have the ability to dissolve bone. They are the largest type of WBCs. Their average diameter ranges from (10-30 )μ and are often referred to as scavenger cells or phagocytes. They only contain one nucleus which is rarely or barely lobed. The nucleus shape in monocytes is often bend-shaped (horseshoe) or kidney-shaped (reniform). Two types of cells can be developed from monocyte cell: macrophages and dendritic cells.   
  • Macrophages are phagocyte cells which eat any type of dead cell in the body. They are larger and live longer than neutrophils and have a large-size single nucleus that is often kidney-shaped. They are also able to act as antigen-presenting cells.
  • Dendritic cells  aid the development of antigen immunity. The shape of the nucleus is small and round-shaped, which as the cell matures, turns into a large nucleus with an irregular star shape and cytoplasmic protrusions (dendrites). 
 Lymphocytes 
Are described according to size and cytoplasmic granularity and can have a small or large nucleus depending on the maturation stage. Small lymphocytes are well-known, and the diameter of a small nucleus ranges from (6 –9)μ, while the diameter of a large nucleus is approximately (10–15)μ. It contains just one nucleus which is rarely or barely lobed. The shape of the nucleus is slightly oval or round and stained dark. Pathologists cannot easily distinguish T-cells and B-cells using traditional light or electron microscopes. They always use an optical microscope  to distinguish between them. 
  • B lymphocytes (B-cells) produce antibodies and proteins that connect to infected microbes or cells of the body and differentiate into a plasma cell in immature stage. They are made in the bone marrow. They have oval nuclei. They have a low fractal dimension and smooth cell surface. Pathologists incubated the slides with Giemsa stain. 
  • T lymphocytes (T-cells) produce proteins called cytokines which help to direct the response of other cells. They have circular nuclei and a wrinkled cell surface. They are stained dark blue.

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