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Connective Tissue(C.T.)

Connective Tissue(C.T.). The mesodermal ………………. to mesenchymal tissue(undifferentiated mesenchymal cells&hemogenous intercellular substance of proteins The mesenchymal tissue are differentiated in the embryo into 1-connective tissue C.T. 2-vascular tissue 3-smooth muscle.

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Connective Tissue(C.T.)

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  1. Connective Tissue(C.T.) The mesodermal ………………. to mesenchymal tissue(undifferentiated mesenchymal cells&hemogenous intercellular substance of proteins The mesenchymal tissue are differentiated in the embryo into 1-connective tissue C.T. 2-vascular tissue 3-smooth muscle

  2. The connective tissue formed of • A-C.T. cells • B-C.T. fibers • C-C.T.matrix

  3. Types of C.T. • According to the nature of intercellular matrix • we have 3 types of connective tissue • 1-C.T. proper( soft matrix) • 2-cartilage (rubbery matrix) • 3-Boney ( solid matrix)

  4. 1-Connective tissue proper • It is called connective because is support,binds&connection various tissue and organs

  5. The C.T. is formed of • 1-C.T. cells • 2-C.T.fibers • 3-Soft matrix or ground substance

  6. Types of connective tissue proper • The cells &C.T. fibers are present in the • soft C.T.

  7. 6 (Six)Types of C.T. Proper • 1-areolar C.T. • 2-yellow elastic C.T. • 3-Mucoid C.T. • 4-White collagen C.T. • 5-Adipose C.T. • 6-Reticular C.T.

  8. Types of Connective tissue cells • 1-Fixed C.T. cells as • 2-Free C.T.Cells

  9. 1-Fixed C.T. cells as: • 1-fibroblast, • 2-fixed macrophages, • 3-fat cells, • 4-mesenchymal cells, • 5-pericyte cells, • 6-endothelial cells • 7-reticular cells

  10. Fibroblast&Fibrocytes Cells • -develop from mesenchymal cells&pericytes • -It is very numerous in areolar C.T. • -basophilic cytoplasm • -The cytoplasm is rich in RNA,ER,GA,Mitochondria • -fibroblast can divide • -Fibroblast can changes into myofibroblast

  11. Function of Fibroblast • - Form collagen,elastin&reticulin substances in order to form C.T.fibers • -Form the mucoprotein of the C.T. matrix • increase number during healing of wounds • Fibroblast change into myofibroblast which close wounds

  12. Fibrocytes === mature fibroblasts • - Small spidle shaped cells with dense nuclei • - Acidophilic cytoplasm • -can not divide

  13. LM of fibroblasts (arrows)

  14. SEM of fibroblasts

  15. 2-Fixed macrophages or histocytes cells • -dervied from blood monocytes • - more present in the damaged C.T. • -have irregular cell membrane • -cytoplasma is not clear-rich in lysosomes • -the nucleus is small ,kidney shape • -Histiocytes cells can be stained with vital stain as trypan blue

  16. Function: • -Defence mechanism of the body • -can engulf(eat)foreign bodies,bacteria and old blood cells • -can clean wound from foreign bodies&debris • -can transport antigens • -macrophage………multinucleatd gint cells…..enclose large foreign bodies in order to destroy them

  17. 3-Adipose cell or fat cells or adipocytes • -derived from mesenchymal cells • - flat peripheral nucleus • -there are 2 types of fat cells • 1-unilocular white fat cells • 2-multilocular brown fat cells • -Fat cells can not divide • Stained : • orange with sudan III,black sudan black

  18. Function • -brown fat responsible for energy reservoir&heat production • -white fat cells release energy during starvation • - support organs as kidney • -they act as heat insulator

  19. 4-The Mesenchymal Cells(UMC) • -embryonic branched cells called(UMC) • -has large oval nucleus&basophilic cytoplasma • -present in the embryonic tissue • Function: • Can differentiate into other types of C.T.

  20. 5-The Pericyte cells • -pale branched cells(peri= around) • -present immediate external to the endothelium of blood vessels capillaries&small venules • -persistent in adult life

  21. Function: • Give rise to both fibroblast&smooth muscle cells • -role in the process of healing of connective tissue • -modified to form myoepithelial cells which can contract

  22. 6-The Endothelial Cells • Present in the surface of blood capillaries&blood vessels • -develop from the embryonic mesenchymal cells

  23. Function: • 1-synthesise collagen(type 4 collagen) • 2-can form the basal lamina of the endothelium • 3-divide rapidly ..give rise..endothelial cells of lung capillaries to secret angiotensin converting enzyme

  24. 7- Reticular Cells • -present in mainly in the reticular C.T. • -modified fibroblast which are specialized to secrete reticular fibres • -reticular cells are found in the stroma of bone marrow,lymph nodes,spleen,liver,pancreas

  25. Function: • Supportive&phagocytic cells • -form the stroma of glands&bone marrow • -removal cellular debris from the lymphatic tissue

  26. 2-Free C.T. Cells • 1-Mast Cells • 2-Plasma Cells • 3-Free Macrophages, • 4-Blood Leucocytes • 5-Melanophore Cells

  27. 1-Mast Cells 2-Histamine secretory mast cells • Present under mucosa of respiratory &digestive tract • Histamine…………….contract smooth muscle • Dilated blood vessels capillaries • Increased the capillary permeability

  28. -Small cells,round,irregular in shape • -present in groups blood vessels • Types of mast cells • 1-Heprin secretory mast cells • Present in the C.T. of skin,secret heprin which is an anticoagulant

  29. TEM of a Mast Cell

  30. LCT – M = mast cell; P = plasma cells; F = fibroblasts; Eo = eosinophils, N = neutrophils

  31. Function: • -Secrete heparin or histamine • (paracrine cells) • -release chemical mediators as immediate hypersensitivity • Factors which may cause of anaphylactic shock

  32. 2-Plasma Cells • Present • peritoneum, submucosa of digestive • respiratory tract, • lymph nodes&spleen • -originate from plasmablast cells which develop from B-lymphocytes • -small&round with hemogenous basophilic cytoplasm

  33. Function: • -secrete specific antibodies against organisms&foreign bodies antibodies circulate in the blood termed(humoral antibodies)&processes is called humoral immunity • -Can not divide • -Have no phagocytic activity

  34. 3-Free Macrophages • -derived from blood monocytes after their migration to C.T. • -their cytoplasma is rich in lysosomes&RER • -they have oval eccentric nuclei

  35. Function: • -Immun system of the body • -they are highly phagocytic cells • -secrete collagenase&elastasa enzymes&lysozome • -kill certain viruses through secretion of interferon

  36. 4-Bolood Leukocytes • Appear normaly in the C.T.of the following body organs • -Eosinophils&basophils • Found in C.T. of respiratory intestinal&female genital tract • -they increase in allergic condition

  37. -Lymphocytes&monocytes • Present in many organs • -increased in number in chronic infections • -Neutrophils: • -They migrate from blood vessels of C.T. • -where acute infection is present in order to phagocytose microorganism

  38. 5-Melanophore pigment cells • -They are C.T.macrophages which phagocytose melanin Pigments are formed by the melanocytes • -melanophores are branched cells with small round nuclei • -melanophore are rich in melanin pigments

  39. Function: • -They carry melanin pigments

  40. Types of C.T.Fibers • There are three(3) types of C.T. • 1-white collagennous fibers • 2-yellow elastic fibers • 3-reticular fibers

  41. 1-White Collagenous Fibers • Shape: • colourless wavy branching bundles,the fibers run paralled to each other • Charcter: • soft,strong&flexible but not elastic fibers

  42. Structures: • formed of protein known as(collagen)which can be digested by pepsin&trypsin enzymes • Staining: • collagenous fibers are acidophilic,stain pink with eosin,red in van-Gison&blue with Mallory stain

  43. Types of collagen • There are five(5) types of collagen • 1-Type I collagen: • Present: • losse C.T.,White fibro-cartilage,bone&teeth this type is formed by fibroblast,osteoblast,odontoblast • 2-Type II collagen: • hyaline&elastic cartilage&formed by chondroblast

  44. 3-Type III collagen: • skin ,smooth muscle&reticular fibers formed by fibroblast&by smooth muscle cells • 4-Type IV • collagen: basement membrane of epithelial tissue&lenes of eye,It formed by fibroblast&by endothelial cells • 5-Type V collagen: • in placenta,it is formed by fibroblast

  45. 2-Elastin fibers • Shape: • fine,straight branching fibers • Carachter: • the fibers branched&anastomose with each other • They run singly&not in bundles • Appear yellow in fresh state

  46. Structures: • formed of protein known as elastin which is resistant to chemical and to boiling • Can digested by the pancreatic elastase enzyme • Staining: • brown with orcein,black with verhoeff and yellow with van-Gison

  47. Orecin Stain for Elastin – purple “ribbon candy”

  48. 3-Reticular Fibers • Shape: • they are thin,branched anastomose to form anetwork or reticulum • Strucures: • -formed of protein known as collagen type III • -Staining: Black with silver

  49. Sliver Stain for Reticular Fibers

  50. PAS stain of epithelial basement membranes (BM)

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