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The Lymphatic System


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The Lymphatic System

  1. 1. The lymphatic organs Dr. Samar Asker
  2. 2. The spleen Single intra abdominal hemo lymphatic organ. To filter the blood from any organism formed of stroma & parenchyma.
  3. 3. Stroma Trabecula e Capsule Reticular CT
  4. 4. a- Capsule: Thick C. T. formed of cells fibroblast ---- collagen & elastic fibers containing smooth muscle fibres. Is covered by peritoneum.
  5. 5. b-Trabeculae: They arise from the hilum of spleen may be from the capsule . Formed of Thick C. T. containing smooth muscle fibres. Divide the spleen into irregular compartments
  6. 6. Reticular CT : formed of cells & fibres in the bacheground stained only with silver{Ag} stain.
  7. 7. Parenchyma: IN fresh sections it shows white spots on red background i.e devided into: White pulp & red Pulp
  8. 8. White pulp = (Malpighian corpuscle): Rounded or oval scattered follicles with an arteriole on one side called central arteriole or follecular arteriole. Formed of reticular CT in which cells are arranged around the arteriole into 4 concentric zones:
  9. 9. B,T, p & M 1. Thymus dependent zone: periarteriolalr lymphatic sheath (PALS) contain Tlymphocytes around the arteriole 2. Germinal center: pale area contain activated large B lymphocytes, plasma blasts, plasma cells & macrophages. 3. Follicular zone= corona: dark contain B lymphocytes 4. Marginal zone : at the periphery contain T& B lymphocytes plasma cells & macrophages. B B p&M T
  10. 10. B B ,T ,p M &
  11. 11. B- red Pulp:red In fresh Formed of : Spleniccords + Blood sinusoids. Splenic cords: Billroth cords the areas between the white pulp & bl. Sinusoids contain blood cells (RBCs+ lymphocytes + monocyts)+plasma cells +Macrophage.
  12. 12. Blood sinusoids. irregular blood spaces lined with fenestrated endothelial cells with non-continuous basement membrane for easy passage of blood cells to the blood. Macrophages appear in the wall of the sinusoids to engulf any foreign bodies
  13. 13. Functions Formation Filtration Storage Blood Immuonological Destruction
  14. 14. Functions 1. Filtration of blood from any organism by macrophages 2. Formation of blood cells : in embryo & lymphocytes in germinal center 3. Storage of blood cells & platelets. 4. Destruction of RBCs& storage of iron. 5. Immuonological function the reticular cells trap the antigen & present it to lymphocytes---- humeral & cell mediated immunity.
  15. 15. Lymph node spleen number multiple Single Function Filterati on of lymph Immunit y Filtration & stores of blood Immunity
  16. 16. Lymph node Capsule Thin, covered with fat Smooth ms only at ,.hilum Trabeculae Thin arise from the capsule spleen Thick covered with peritoneum rich in smooth muscle Thick arise from the hilum
  17. 17. Lymph node Parenchy ma Cells Cortex & medulla Cortex = lymph follicle & lymph sinus The follicles have no .arteriol Medulla = Medullary cords & Medullary . sinuses lymphocytes + .macrophages + plasma spleen White pulp & red pulp White pulp = lymph follicle . no sinuses .The follicle contain arteriole Red pulp = splenic cords & . blood sinusoids macrophages + plasma cells + WBCs +RBCs
  18. 18. Tonsils Partially capsulated lymphatic tissue 3 sites:
  19. 19. Palatine tonsils Two oval masses of lymphatic tissue under the mucous membrane of oropharynx.
  20. 20. Lymphatic tissue of two kinds: Lymph follicle with or without germinal center Diffuse lymphatic tissue: lymphocytes and plasma cells & macrophage.
  21. 21.  Each tonsils is covered with stratified squamous epithelium which dips into the underlying lymphatic tissue to crypts.
  22. 22. mucous glands deep to the follicle their ducts open to the surface & not in the base of the crypt so inflamatin is common
  23. 23. Incomplete capsule: separates the tonsils from the underlying structure. Salivary corpuscle: Lymphocyte which pentrate the epith. To appear in the saliva.
  24. 24. Lingual tonsil: At the base of the tongue . Secondary follicle & diffuse lymphatic.  Non keratinised str. Sqam.epth which form crypt. mucous glands open into the base of the crypt.
  25. 25. Pharyngeal Tonsil Single mass of lymphoid tissue under nasopharynex. Covered with pseudo stratified columnar ciliated epith. with goblet cells Folded with no crypt Function :at the beginning of the respiratory &digestive systems so protect from bacteria & produce Ab