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SPLEEN. LYMPH NODE.
SPLEEN.
SPLEEN (and lymph node) is PERIPHERAL hemopoietic organ, because it fulfils function of antigen DEPENDENT proliferation and differentiation of B-lymphocytes in B-zones and antigen DEPENDENT proliferation and differentiation of T-lymphocytes in T-zones.
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Strucrure. Connective tissue capsule, connective tissue septa (or trabecula) extend from capsule. Both contain smooth muscle cells and are able to contract. Space between trabeculas is composed of: A) Stroma and B) parenchyma.
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Stroma is reticular tissue. It forms 3D-mashwork. Inside loops of this mashwork two types of blood formed elements locate :lymphocytes and RBCs. These formed elements is parenchyma.
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Parenchyma presented by 2 components A) RED PULP and B) WHITE PULP.
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White pulp – is aggregations of T- and B- lymphocytes. It means- parenchyma of white pulp is lymphoid tissue.
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White pulp morphologically is composed of 2 components: A) lymphoid (or lymphatic) nodules and B) PALS – periarterial lymphatic sheath.
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Lymphoid nodule is round aggregation of B- lymphocytes. Functionally nodule is B-zone. Function of nodule, as B-zone, is - antigenDEPENDENT proliferation and differentiation of B-lymphocytes. It result is - formation of plasma cells from naïve B-lymphocyte. Plasma cells secrete 5 classes of immunoglobulins (Igs, antibodies).
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Lymphoid nodules of spleen against nodules of lymph node, distribute in spleen throughout the organ (diffuse distribution). Each nodule has CENTRAL ARTERY.
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PALS is aggregation of T- lymphocytes. Functionally PALS is T-zone. Function of it, as T-zone, is - antigenDEPENDENT proliferation and differentiation of T-lymphocytes.
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Red pulp is 2 components: A) aggregation of erythrocytes and macrophages in loops of reticular tissue, outside of capillary lumen, directly in stroma. It is splenic cords, or Bilroth cords. Function- macrophages eliminate old RBCs. B) aggregation of erythrocytes inside lumen of sinusoidal capillary. Function- is blood storage.
LYMPH NODE.
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Structure. Connective tissue capsule, connective tissue septa (or trabecula) extend from capsule. Space between trabeculas is composed of: A) Stroma and B) parenchyma.
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Stroma is reticular tissue. It forms 3D-mashwork. Inside loops of this mashwork T- and B-lymphocytes locate. It means- parenchyma is lymphoid tissue.
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Lymphocytes arranged into 3 layers: A) outer (or superficial) cortex, B) deep cortex, or paracortex, C) medulla.
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Outer cortex is composed of lymphoid (or lymphatic) nodules. Functionally nodule is B-zone. Function of it, as B-zone, is - antigenDEPENDENT proliferation and differentiation of B-lymphocytes. It result is - formation of plasma cells from naïve B-lymphocyte.
Plasma cells secrete 5 classes of immunoglobulins.
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Lymphoid nodules of lymph node against nodules of spleen, locate strictly and only in outer cortex. Each nodule has NOT CENTRAL ARTERY.
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Paracortex (or deep cortex) is composed of diffuse arranged T-lymphocytes. Functionally paracortex is T-zone. It function is - antigenDEPENDENT proliferation and differentiation of T-lymphocytes.
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Medulla is composed of medullary cords. Each cord is elongated aggregation of B-lymphocytes. Functionally medullary cords are B-zone. Function of it, as B-zone, is - antigenDEPENDENT proliferation and differentiation of B-lymphocytes. It result is formation of plasma cells from naïve B-lymphocyte.
Составитель – доцент В.В. Бондаренко.
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