Exam 1 Review:  Chapter 17:  Leukocytes and Derivatives

granulocyte - Any of a group of white blood cells having many large granules in their cytoplasm and distinctive lobular (polymorphic) nuclei; three subgroups are recognized based on the staining properties of the granules:  neutrophils, eosinophils, and basophils.

neutrophil = polymorphonuclear leukocyte - The most abundant type of granulocytic white blood cell (60-70% of total WBCs) which is the rapid responder to sites of injury and inflammation and is highly destructive of microorganisms, especially bacteria; its granules stain poorly and appear pale gray to lavender in typical blood stains; it is capable of phagocytosis and will participate in the removal of damaged tissues even in the absence of infection.

eosinophil - The type of granulocytic white blood cell (2-4% of total WBCs), containing large cytoplasmic granules which are stained red by eosin or other acid dyes; it is capable of phagocytosis and participates primarily in immune responses against multicellular parasites (worms) and is also involved in certain hypersensitivities (allergies).

basophil - The least abundant type of white blood cell (0.5-1.0% of total WBCs); a non-phagocytic granulocyte containing large cytoplasmic granules which are stained blue with basic dyes; the granules contain immune regulatory substances including heparin, histamine and serotonin; these cells resemble and may be developmentally related to tissue mast cells (tissue basophils).

mast cell - A cell found widely dispersed in very low numbers in connective tissue which contains numerous large basophilic granules; the granules contain immune regulatory substances including heparin, histamine and serotonin which it releases in response to injury or inflammation of body tissues; it is also implicated in the symptoms of allergies; these cells resemble and may be developmentally related to blood basophils.

agranulocyte - Any of a group of white blood cells having only a few small granules in their cytoplasm; two subgroups are recognized based on their size, the morphology of their cytoplasm and their distinctive nuclei: lymphocytes and monocytes.

monocyte - The largest type of white blood cell (3-8% of total WBCs); a phagocytic agranulocyte, having a single well-defined, often kidney-bean shaped, nucleus and very fine granulation in the cytoplasm; they have long lifespans and when they emigrate into tissues they differentiate into various types of macrophages; they are slow responders to sites of injury and inflammation and are highly destructive of microorganisms.

macrophage - Any of the large long-lived phagocytic cells derived from monocytes comprising a major component of the diffuse immune system (sometimes called the reticuloendothelial system or, more recently, the mononuclear phagocytic system); macrophages from different sites have somewhat different properties; in addition to contributing to the killing of microorganisms and tumor cells; the release immune regulatory substances and play a vital role in antigen-presentation leading to the production of antibodies by B lymphocytes and the activation of T lymphocytes.

lymphocyte - The smallest type of white blood cell (20-25% of total WBCs); a non-phagocytic agranulocyte, having a single well-defined, round, darkly-staining nucleus and a thin rim of cytoplasm with very fine granulation; they have long lifespans and play diverse roles in immune responses; several developmental subgroups are recognized, differentiated by their maturation processes and by the differences in cell surface markers they express:  B cells, which function in humoral immunity, and T cells, N (null) cells and NK (natural killer) cells, which function in cellular immunity and non-specific immunity; the majority of these cells will be found in the bone marrow and the secondary lymphatic organs.

plasma cell - Any of the antibody-secreting (immunoglobulin-secreting) cells found in lymphoid tissue, and in small numbers in blood, red bone marrow, and other connective tissues; they are derived from B lymphocytes = B cells in a complex process requiring lymphokine stimulation and reaction with a specific antigen, and usually the participation of antigen-presenting macrophages and T lymphocytes = T cells; they are larger than ordinary B lymphocytes, with more cytoplasm, an eccentric nucleus, and sometimes patch of pale cytoplasm near the nucleus which represents a faintly visible enlarged and active Golgi apparatus where the antibodies are being packaged for storage and secretion.

B lymphocyte = B cell - A functional subclass of  lymphocytes, originating and maturing in the bone marrow; identified by the specific cell surface markers they express; they function in humoral immunity; they make antibodies = immunoglobulins in a complex process requiring lymphokine stimulation and reaction with a specific antigens, and usually the participation of antigen-presenting macrophages and T lymphocytes = T cells; when actively involved in immune defense they may transform into plasma cells; any one B lymphocyte makes only one specific antibody; the majority of these cells will be found in the bone marrow and the secondary lymphatic organs.

T lymphocyte = T cell - A functional subclass of  lymphocytes, originating in the bone marrow and and maturing in the thymus; identified by the specific cell surface markers they express; (they do not make antibodies = immunoglobulins); they function in cellular immunity; they orchestrates and regulate many of the immune system's responses; several functional subcategories are recognized including memory T cells, helper T cells, suppressor T cells, cytotoxic T cells, and delayed hypersensitivity T cells; the majority of these cells will be found in the bone marrow and the secondary lymphatic organs.

memory B cell - A functional subclass of  B lymphocytes, which are produced after a B lymphocyte clone has become active in specific antibody = immunoglobulin production against a specific antigen; these cells are dormant during the initial response to antigen, but serve as rapid responders to any subsequent exposure of the individual to the specific antigen which was initially involved in their production; their presence insures that subsequent exposures to the specific antigen are met with a more rapid and powerful response; the majority of these cells will be found in the bone marrow and the secondary lymphatic organs.

memory T cell - A functional subclass of  T lymphocytes, which are produced after a T lymphocyte clone has become active in some specific cell-mediated response against a specific antigen; these cells are dormant during the initial response to antigen, but serve as rapid responders to any subsequent exposure of the individual to the specific antigen which was initially involved in their production; their presence insures that subsequent exposures to the specific antigen are met with a more rapid and powerful response; the majority of these cells will be found in the bone marrow and the secondary lymphatic organs.

fixed macrophage - Any monocyte-derived phagocyte which is stationary within connective tissue of a particular organ; it displays finger-like projections of its surface folds to permit contact with passing particles; it carries out a scavenging, phagocytic role at its site of tethering; examples include:

• Kuppfer cells -- liver
• microglia -- central nervous system
• alveolar macrophages -- alveolar walls in the lungs
• pleural and peritoneal macrophages -- serous cavities
• osteoclasts -- bone
• Langerhans cells -- epidermis

wandering macrophage - Any monocyte-derived scavenging phagocyte which leaves the blood and patrols through the tissues of the body; they respond slowly and migrate to injured, inflamed or infected tissue sites.

List:

4. The five types of leukocytes and their functions.

 10.  The five types of white blood cells in the order of their relative frequency from most to least percentage found in a normal person's blood.

Describe:

1. The physical similarities and differences between the five types of leukocytes.

          (1)  All capable of amoeboid movement to exit the blood stream and patrol tissues.
          (2)  Granulocytes (neutrophils = polymorphonuclear leukocytes, eosinophils, basophils) have many large cytoplasmic granules (eosinophil granules take up (often red) acidic stains; basophil granules take up (often blue/purple) basic stains; neutrophil = polymorphonuclear leukocyte granules take up neither type of stain well and so stain pale grayish lavendar).
          (3)  Agranulocytes (lymphocytes and monocytes) lack the large cytoplasmic granules seen in granulocytes, though they do have small numbers of much smaller cytoplasmic granules.
          (4)  Granulocytes (neutrophils = polymorphonuclear leukocytes, eosinophils, basophils) have compacted, dark-staining, multi-lobed nuclei.
          (5)  Agranulocytes (lymphocytes and monocytes) have larger rounded nuclei; lymphocytes have a round nucleus and monocytes a more oval or bean-shaped nucleus.
          (6)  Monocytes are the largest of the WBCs and have the largest nuclei; the granulocytes (neutrophils = polymorphonuclear leukocytes, eosinophils, basophils) are all similar in size and intermediate in size; the lymphocytes are the smallest, usually about the same diameter as an erythrocyte = RBC or just slightly larger;  the difference in size is primarily due to the amount of cytoplasm present in each cell type; their nuclear volumes are similar.

Granulocytes	Lymphocytes	Monocytes