Immune system
General outline
Lymphatic organs: thymus, lymph node, spleen, tonsil Lymphoid tissue T：Th、Ts、Tc B Lymphocyte K NK Cells Macrophage
Lymphoid tissue:
consists of reticular tissue, macrophage, plasma
cell and lymphocyte
diffuse L.T.: no border, predominant T cell , postcapillary venules (P.C.V.)
lymphoid nodules: clear border, predominant B cells Ag Primary ~ Secondary ~
lymphoid tissue
Lymphoid organs
Central lymphoid organs Thymus: the generation place of Tc Bone marrow: the generation place of Bc Peripheral lymphoid organs Contain lymph node, spleen, tonsil
The places to proceed immune reactions
Thymus
Structure:
Capsule ( C.T.) Cortex: interlobular septa Endothelial reticular cell (ERC) Lymphocyte: thymocyte
Macrophage: secrete IL-1
ERC Lc: few Medulla: Macrophage: secrete IL-1 Thymic corpuscles
Thymus
The cortex of thymus
The medulla of thymus
Blood-thymus barrier:
Prevents circular antigens from reaching the thymic cortex where T cells are being formed Consists of : endothelial cell of continuous capillary very thick basement membrane
perivascular space with macrophage in it
basement membrane of ERC
ERC or their processes with desmosome
Thymus function:
the thymic ERC can secrete thymic hormones (thymosin, thymolin, thymopoietin) induce the stem cell to differentiate into T lymphocyte
Lymph node
scattered in the passages of lymph capsule structure Cortex
parenchyma
medulla
function
Perform immune reaction Filtration of lymph
Structure:
capsule: several afferent lymphatic vessels, trabecula cortex primary lymphoid nodule (B) secondary superficial cortex: internodule zone paracortical zone: diffuse lymphoid tissue(T) cortical lymphatic sinuses
subcapsular sinus
peritrabecular sinus
Medulla
medullary cords: contain many B cells, plasma cells, macrophages
medullary sinuses many macrophages
Lymph node
The cortex of lymph node
The medulla of lymph node
Recirculation of lymphocytes:
Lymphoid tissue Efferent lymphatic vessel
P.C.V.
Blood circulation
Spleen
located in the passages of blood
capsule
structure white pulp parenchyma red pulp marginal zone function immune filter blood to clear out the old red blood cells hemopoiesis blood storage
Structure:
capsule: D.C.T. containing smooth muscle; is covered by mesothelium white pulp
periarterial lymphatic sheath: T predominant
lymphatic nodules (splenic nodules): B
marginal zone lies between the white pulp and the red pulp
red pulp splenic sinusoid long rod endothelial cells ; gaps between the adjacent cells; no basement membrane; rounded by reticular fibers splenic cord the main components are B, Mφ, etc; is the principle place for filtration of blood
Spleen
The white pulp of spleen
The red pulp of spleen
Tonsil
Mucosa stratified squamous epithelium Epithelium form crypts lymphocyte infiltration lymphatic nodules diffuse lymphatic tissue Capsule: C.T.
Lamina propria
Tonsil
Mononuclear phagocyte system
young monocyte Bone marrow Blood monocyte
Tissues or organs
CT: macrophage Liver: Kuffer cell Lung: dust cell Nerve tissue: microglia Osseous tissue: osteoclast Skin: Langerhans cell
Function of MPS: phagocytosis participate in immune reaction secrete bioactive substances