2. CONNECTIVE TISSUE Department of histology, cytology and embryology 2013 medical students Kharkov National Medical University

3. CONNECTIVE TISSUE Connects other tissues, underlies or surrounds them.Connects other tissues, underlies or surrounds them. Produces and maintains many different intercellular substances.Produces and maintains many different intercellular substances. Provides support and nourishment.Provides support and nourishment.

4. Connective Tissues Classification ： Blood & lymph Connective tissue proper : Loose connective tissue Dense connective tissue Adipose tissue Specialized Reticular tissue Mucoid tissue Pigment tissue Cartilage & bone

5. Note: All Connective Tissues have: Common origin - from mesenchyme Common structure Cells + Extracellular substance Common similar) functions

6. Note: Connective Tissues contain a high ratio of extracellular matrix to cells. extracellular matrix is mostly secreted by cells, which are embedded in it. extracellular matrix 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.

7. Embryonic Connective Tissue --- Mesenchyme Consists of cells and ground substance with reticular fibers Gives rise to all types of Connective Tissues

8. 1 st group - Fixed cells (intrinsic) – stable population:1 st group - Fixed cells (intrinsic) – stable population: 1. fibroblast – main cells, produce fibers1. fibroblast – main cells, produce fibers 2. adipocyte2. adipocyte 3. reticular cell3. reticular cell 4. pericyte4. pericyte 5. undifferentiated cells(adventitial, perivascular – stem cell) All arise from mesenchyme. 6. Pigment cell – is from neural crest.6. Pigment cell – is from neural crest. Connective tissue cells:

9. 2 nd group - Mobile cells – are the blood2 nd group - Mobile cells – are the blood leucocytes. Connective tissue cells:

10. Fibroblast is fiber forming cell Mature fibroblast is called fibrocyte.

11. Adipocytes (fat cells) function as store house, mechanical support, conservation of body heat.

12. Mobile cells = blood leukocytes Macrophage blood monocyte ps er ph lys

13. Plasma cell B-lymphocyte

14. Mast cells = basophils.

15. All types of T-lymphocytesAll types of T-lymphocytes Microphage = neutrophilMicrophage = neutrophil Tissue eosinophilTissue eosinophil Other mobile cells:

17. Consists of cells and extracellular matrix, including fibers and ground substance. Classified: as loose or dense regular or irregular Connective tissue proper

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

19. Loose (Areolar) is always irreguar CT Dense: –Dense regular CT –Dense irregular CT

20. Loose irregular connective tissue (L.I.C.T.) Is the most distributed it contains blood vessels

21. The Cells and Fibers of L.I.C.T.

22. General components of matrix : 1. Fibers and 2. Ground substance – is a gel containing: water, salts and 3 kinds of molecules containing carbohydrates: –glycosaminoglycan or GAG, –proteoglycans and –glycoproteins

23. Extracellular matrix (ECM)

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

25. Hylauronidase is an enzyme produced by WBC’s, sperm and some bacteria. Injection of hyaluronidase can speed the passage of drugs and fluid through the tissue.

26. Types of C. T. Fibers Three types of fibers –Collagen fibers Strongest and most abundant Tensile strength > steel –Elastic fibers “Yellow fibers” Long, thin, branching fibers Can stretch and recoil –Reticular fibers Fine collagenous fibers

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

28. Mechanical support Protection Exchange of metabolites. Homeostasis Protection against infections Repair after injury, plastic function Connective tissue proper Functions:

29. Cooperation of blood and connective tissue cells for: Local reaction - inflammation General immunological reaction LCT: protection against infections, noxious agents:

30. High regenerative capacity (fibroblast) Fibrous scar formation NOTE! LCT carries additional functions Repair after injury, plastic function of LCT

31. Other types of Connective tissue proper (CTP): Dense Regular CTP Dense Irregular CTP Fibers are predominant elements

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

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

34. Connective tissue specialised Adipose: Location – deep to skin: sides, buttocks, breasts; padding around eyeballs and kidneys Function – insulation, mechanical support, stores energy. Reticular: Location – spleen, lymph nodes, bone marrow Function – supporting framework for haemopoietic organs Mucoid: umbilical cord, incompressible

35. Adipose Tissue