1. 1. The lymphatic organs Dr. Samar AskerDr. Samar Asker
2. 2. The spleen Single intra abdominal hemo lymphatic organ. To filter the blood from any organism
3. 3. a- Capsule: Thick C. T. formed of fibroblast collagen & elastic fibers containing smooth muscle fibres. Is covered by peritoneum. Stroma:
4. 4. 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. The capsule and trabeculae contain blood vessels and nerves.
5. 5. Reticular CT : formed of cells & fibres in the bacheground stained only with silver{Ag} stain.
6. 6. Parenchyma In fresh sections it shows white spots on red background i.e devided into: White pulp & red Pulp
7. 7. 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:
8. 8. 1.Thymus dependent zone: periarterial lymphatic sheath (PALS) contain T- lymphocytes around the central arteriole 2-Germinal center: pale area contain activated large B lymphocytes, plasmablasts, plasma cells & macrophages.
9. 9. Follicular zone= corona: dark contain B lymphocytes Marginal zone : at the periphery contain: T& B lymphocytes plasma cells & macrophages.
10. 10. Red Pulp: Formed of : Splenic cords Blood sinusoids.
11. 11. Splenic cords= Billroth cords The areas between the white pulp & bl. Sinusoids contain blood cells: (RBCs, WBCs ,lymphocytes , monocyts) plasma cells Macrophage.
12. 12. Blood sinusoids. Irregular blood spaces lined with fenestrated endothelial cells & 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. Filtration Formation Storage DestructionBlood Functions Immuonological
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 spleen Capsule Thin, covered with fat Smooth ms only at hilum., Thick covered with peritoneum rich in smooth muscle Trabeculae Thin arise from the capsule Thick arise from the hilum
17. 17. Lymph node spleen Parenchy ma Cortex & medulla Cortex = lymph follicle & lymph sinus The follicles have no arteriol. Medulla = Medullary cords & Medullary sinuses. White pulp & red pulp White pulp = lymph follicle no sinuses. The follicle contain arteriole. Red pulp = splenic cords & blood sinusoids. Cells lymphocytes + macrophages + plasma. macrophages + plasma cells + WBCs +RBCs
18. 18. Tonsils Partially capsulated lymphatic tissue 3 sites: Palatine tonsils Lingual tonsil Pharyngeal Tonsil
19. 19. Palatine tonsilsPalatine tonsils Two oval masses ofTwo oval masses of lymphatic tissue under thelymphatic tissue under the mucous membrane of oro-mucous membrane of oro- pharynx.pharynx.
20. 20. Lymphatic tissue of two kinds: Lymph follicle with or without germinal center Diffuse lymphatic tissue: Lymphocytes plasma cells macrophage.
21. 21. Each tonsils is coveredEach tonsils is covered withwith stratified squamous epitheliumstratified squamous epithelium which dips into the underlyingwhich dips into the underlying lymphatic tissue to crypts.lymphatic tissue to crypts.
22. 22. mucous glandsmucous glands deep to thedeep to the folliclefollicle theirtheir ducts open toducts open to the surface &the surface & not in the basenot in the base of the crypt soof the crypt so inflammation isinflammation is commoncommon
23. 23. Incomplete capsule: separates the tonsils from the underlying structure. Salivary corpuscle: Lymphocyte which pentrate the epith. To appear in the
24. 24. Lingual tonsil: At the base of the tongue Secondary follicle & diffuse lymphatic. Non keratinised str. Sqam.epth which form crypt. mucous glandsmucous glands openopen into the base of the crypt.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.
26. 26. Medium sized artery & vein
27. 27. Lymph node
28. 28. The spleen
29. 29. central arteriole
30. 30. Palatine tonsilsPalatine tonsils