Kharkov National Medical University

1. Kharkov National Medical University LECTURE for dentistry students Department of Histology, cytology and embryology

2. Connective TissuesClassification： Blood & lymph Connective tissue proper Connective tissue specialized Cartilage Bone

3. C T-s • Common origin - from mesenchyme • Common structure Cells, Extracellular substance • Common (similar) functions

4. Unlike other tissues, CT-s contain a high ratio of extracellular matrix (ECM) to cells. • ECMis secreted by cells, which are embedded in it. • ECM varies for different tissues and provides their structural and functional features. • Examples : the fluid part of blood the hard part of bone, the tough part of fascia, the resilient part of cartilage.

5. Blood. Functions • Exchange of metabolites • Exchange of gases • Homeostasis

6. Blood • Plasma 90 -93 % -water lipids, proteins, carbohydrates • Erythrocytes (RBC) • Leukocytes (WBC) • Platelets

8. Erythrocytes - woman have 4-5 million in mm3, men - 5-6 million. • are non-nucleated, biconcave discs filled with hemoglobin. • they carry oxygen to the cells. • erythrocytosis • erythropenia

9. Leukocytes – 7000 in mm3 • Granulocytes • Agranulocytes • Leukocytosis • Leucopenia

10. 1. Neutrophils - 50-70% of the WBC's • The nucleus is multi-lobed • Granules are tiny and pale neutral. • Microphage, it plays a primary role in inflammation.

11. 2. Basophils- 0,5 – 1 % of the WBC's • Their basophilic granules contain histamine (vasodilator) and heparin (anticoagulant).

12. 3. Eosinophils – 3 - 5% of the WBC's • The granules are pink, contain digestive enzymes against parasitic infection and allergic reactions. • They phagocytize antigen - antibody complexes.

13. Agranulocytes 1.Lymphocyte • cell with very thin clear cytoplasm which stains pale blue. • Its nucleus is very large and stains dark purple. • - 25-35% .

14. function • Immune response. • The T-lymphocytes act against virus infected cells and tumor cells. • The B-lymphocytes produce antibodies. • At AIDS T-cell is an indicator of the AIDS virus' activity.

15. Lymphocytes, EM

16. 2. Monocytesare the largest cells, • The nucleus is indented or C-shaped. • They are phagocytes and become highly activated with foreign antigen. • - 5 - 8% of the leukocytes

17. Monocyte, EM

18. Platelets • Platelets are patricles of cytoplasm, • important for blood clotting. • - 180,000 to 320,000 in mm3.

19. Platelets

20. Platelets – form from giant myeloid cells called megakaryocytes (60 to 100 um in diameter). Cytoplasmic processes of this cell extend into marrow sinuses and fragment away. These cellular fragments are the platelets or thrombocytes. • a. They are membrane-bound sacs. • b. They are 2 to 5 um in diameter. • c. The periphery of the platelet is a colorless and homogeneous region • called the Hyalomere. • d. The central area or chromomere contains azure-colored granules. The granules contain several different substances: • i.   heparin – an anticoagulantii.  histamine – triggers inflamationiii. serotonin – elicits painiv. platelet-derived growth factor (PDGF) - stimulates tissue        regeneration to promote healingv. thromboplastin – promotes blood clotting

21. Connective tissue proper (CTP ) CTP is widely distributed. It forms the capsules and thin septa of all others tissues and all organs, always underlines epithelia. It contains blood vessels, through its ground substance all nutrients and waste products diffuse between the blood and all other tissues.

22. CTPfunctions: • Mechanical support, protection • Exchange of metabolites. Homeostasis • Protection against infections • Repair after injury, plastic function

23. CTP • Consists of cells and • ECM, including fibers and ground substance.

24. Classification • loose – has predominance of ground substance • dense– has predominance of fibers • regular – fibers form parallel bundles • irregular – fibers are disordered

25. Loose (Areolar) is always irreguar CT

26. Loose irregular connective tissue (LICT) • Is the most distributed • just it contains blood vessels

27. The Cells and Fibers of LICT

28. LICT cells: • Fixed cells (intrinsic) – stable population: arise from mesenchyme. • Mobile cells

29. Fixed 1. Fibroblast is a fiber forming cell (regeneration)

30. Fixed2. Adipocytes (fat cells).Function as store house, mechanical support, conservation of body heat.

31. Other fixed cells: • 3. Reticular • 4. Pericytes • 5. Undifferentiated (adventitial, perivascular – stem cell) • 6. Pigment cell -is from neural crest.

32. Mobile cells = blood leukocytes Macrophage = blood monocyte is antigen presenting cell ps ph er lys

33. Plasma cell = B-lymphocyte

34. Mast cells = basophil .

35. Other mobile cells: • All types of T-lymphocytes • Microphage = neutrophil • Tissue eosinophil

36. General components of ECMs: 1. Fibers and 2. Ground substance – is a gel containing: • water, salts and • glycosaminoglycans or GAG, • proteoglycans and • glycoproteins

37. Extracellular matrix (ECM)

38. Features of ground substance: • Permeability • Barrier to the penetration of bacteria

39. Types of C T Fibers • Three types of fibers provide support • Collagen -Strongest and most abundant Tensile strength > steel • Elastic -“Yellow fibers” • Long, thin, branching • Can stretch and recoil • Reticular - Fine collagen fibers

40. LCT protection against infections,noxious agents: • Immunological reaction

42. Repair after injury, plastic function of LCT • High regenerative capacity (fibroblast) • Fibrous scar formation

43. Other types of Connective tissue proper (CTP):

44. Dense Regular Connective Tissue fibrocyte • Collagen fibers form parallel bundles • fibrocytes tendons, aponeuroses Tensile strength in one direction

45. Dense Irregular Connective Tissue Fidrocyte • Collagen fibers are irregularly arranged • Tissue can resist tension from any direction • Very tough tissue -- dermis of skin

46. Connective tissue specialised • Adipose: • –Reticular: • Function – supporting haemopoietic organs • Mucoid: umbilical cord, imcompressible

47. Adipose Tissue

48. Cartilage

49. Functions: Semi-rigid extracellular matrix withstands to compression, flexible. Supports soft tissues. Smooth surface allows sliding against it. Essential for growth, development of bone.

50. Characteristics 1.Cells: Chondroblasts located in the inner pericondrium – production of ECM Chondrocytes located in lacunae, maintain matrix 2.Extensive ECM Fibers and ground substance: water (withstands to compression), hyaluronic acid, proteoglycans, glycoproteins Avascular