HEMATOPOEITIC SYSTEM: Blood cells Bone Marrow Spleen Thymus Lymph nodes
Giemsa stained human blood smear with Red blood cells, platelets, neutrophil, lymphocyte
Giemsa stained human blood smear with Red blood cells, platelets, neutrophil, eosinophil, monocyte
Circulating Red cells,--precursors are in bone marrow, rbcs are made to circulate about 120 days, and are destroyed in the spleen Platelets--precursors in bone marrow are megakaryocytes Circulating White blood cells: composed of Neutrophils: cells with segmented nuclei and neutral cytoplasmic granules Lymphocytes: mononuclear cells, hardly any cytoplasm Monocytes: small population of mononuclear cells with more cytoplasm Eosinophils: occasional, cells with segmented nuclei and red cytoplasmic granules. Increased in allergies Basophils: rare: cells with segmented nuclei and basophilic (blue) cytoplasmic granules, store histamine granules
Circulating monocytes when infiltrate into tissue settle into tissue macrophages Macrophages are really abundant in lung, liver and spleen, ---are also found in all organs, (and in the brain are called microglia) Circulating basophils when they infiltrate into tissue, settle into tissue mast cells (?). Mast cells are abundant in the gut
Separation of blood components in a test tube if blood is not clotted(anticoagulant added to tube and centrifuge to separate): cells and plasma plasma White blood cells(wbc) Red blood cells (rbc) Blood in a test-tube if blood is clotted: cells and serum Anticoagulant may be citrate, EDTA or More separation methods
Blood cells Bone Marrow Spleen Thymus Lymph nodes
A Bone Marrow smear may be made similarly to the blood smear
Decalcification solutions HCl; Formalin+ HCl; EDTA only- for slow decalcification for IHC
A normal bone marrow examination will show different populations of cells
Shops a proliferation of one clone of cells, in this case mature B cells, which secrete Ig
Blood cells Bone Marrow Spleen Thymus Lymph nodes
Human Spleen! Mouse Spleen!
Tissue placed on sponges allow orientation. Ask what assays you will use the tissue and that will determine whether the tissue undergoes Fixation or Freezing for immunohistochemistry or extracts
Use labeled cassettes, to fix thin slices of organs or rolls of intestine, for at least 24 hours, before transferring to 70% alcohol, for processing into paraffin blocks
Mouse Spleen appears a little different on the scale of things but has similarities in morphology and function white pulp =lymphoid follicles and red pulp which has supporting stroma with fibroblasts, macrophages, and blood coursing through spaces called sinuses, lined by endothelial cells
A fibrous tissue capsule surrounds the spleen giving some support Trabeculae of fibrous bands travel into the parenchyma of the spleen ot continue the supporting role
Blood vessels travel within the fibrous support bands and lymphocytes travel along with the blood vessels to form follicles of lymphoid tissue white pulp within the spleen
These lymphoid follicles of form PALS-periarteriolar lymphoid sheaths, with T cells and B cells
The red pulp of the spleen is formed of trabeculae and sinusoids. These are lined by discontinous capillaries and carry circulating blood cells. Many monocytes migrate into the tissue and become macrophages.
Splenic red pulp with sinusoids and hematogenous cellsx400
Spleen with macrophages highlighted, showing the phagic activity which is important In clearing debris
Mouse spleen is different from human spleen in containing abundant megakaryocytes at the periphery of the follicles
Spleen panel The spleen from the control animal shows well delineated follicles separated by red pulp, in which differing cell types, (all of which appear mature), can be visualized coursing through the sinusoids.! The spleen froms M3 animal shows an effacement of the lymphoid follicles and an infiltration of the red pulp with mononuclear cells, many of which have a uniform morphology! The spleen from M4 animal similarly shows an effacement of the lymphoid follicles and an infiltration of the red pulp with immature mononuclear cells, all of which have large nuclei, decreased nuclear: cytoplasmic ratios, and some with prominent nucleoli.!
Blood cells Bone Marrow Spleen Thymus Lymph nodes
Trachea, Heart, Lung, Thymus The thymus lies above the heart under the sternum of the rib cage
Mouse Spleen appears a little different on the scale of things but has similarities in morphology and function white pulp =lymphoid follicles and Thymus red pulp which has supporting stroma with fibroblasts, macrophages, and blood coursing through spaces called sinuses, lined by endothelial cells
The Human and the Mouse Thymus has an outer cortex, with immature T lymphocytes and a medulla with more mature T cells. The medulla has epithelial cells which help maturation.
Blood cells Bone Marrow Spleen Thymus Lymph nodes
Lymph node normal morphology may vary!
Gut-associated lymphoid tissue or Peyer s patches are sub-epithelial collections of lymphocytes
Peyer's patches (after Johann K. Peyer, 1653-1712, a Swiss anatomist)!
Lymphoid foliicles epithelium Human Tonsil Hematoxylin &Eosin stain x100
Lymphoid foliicles epithelium Human Tonsil biotinylated PNA/ HRP Streptavidin/ NovaRed substrate/hematoxylin x100
Pathological abnormalities of lymph nodes include: ---Hyperplasia, reaction to infections in the body ---Primary malignancy---lymphomas--b cell neoplasms and T cell neoplasms are common--neoplasms of the other cell types also occur. --- metastatic malignancies--usually of epithelial origin-- metastatic carcinomas
Leukemia = white cells, malignant, travelling in blood stream Lymphoma = oma or tumor made up of white cells--malignant lymphocytes, monocytes, granulocytes