1. CONNECTIVE TISSUE

2. Origin of connective tissue cells

3. LOOSE CONNECTIVE TISSUE Characterized by loosely arranged fibers and an abundance of cells The primary location is : beneath those epithelia that cover the body surfaces and line the internal surfaces of the body In association with the epithelium of glands surrounds the small vessels

4. Loose connective tissue (scheme)

5. Light micrograph of loose C.T.

6. Connective tissue cells can be categorized as fixed and wandering Fixed cell populationWandering cell population -Fibroblasts- Lymphocytes -Myofibroblasts- Plasma cells -Macrophages- Neutrophils -Mast cells - Eosinophils -Adipose cells- Basophils -Reticular cells - Monocytes -Undifferentiated stem cells

7. E.M. of fibroblast portion with the adjusting collagen fibers

8. E.M. of a macrophage surrounded with collagen fibers

9. L.M. of macrophages in liver (von Kupffer cells)

11. Specific names of different location macrophages (macrophage system) Monocytes (blood) Macrophages-histiocytes (connective tissue) Dust cells (lung alveoli) Kupffer cells (liver) Langerhans cells (skin) Hofbauer cells (placenta) Osteoclasts (bone) Microglia (brain) Dendritic cells (lymphoid organs) Microfold (M) cells (intestine)

12. E.M. of a mast cell

14. Physiologically active substances secreted by mast cells

17. E.M. of adipocytes on different stages of maturation

18. Plasma cell schematic representation

21. NON-CELLULAR COMPONENTS OF CONNECTIVE TISSUE Fibers Collagen fibers – forms the most abundant fibers of connective tissue Reticular fibers – provide a supporting framework for the cellular constituents of lymphoid organs mostly Elastic fibers – provide tissues with the ability to respond to stretch and distension Ground substance – consists largely of highly hydrated proteoglycans, of hyaluronic acid, and GAG (chodroitin-sulphate, heparan-sulphate, dermatan- sulphate, keratan-sulphate)

25. CLASSIFICATION OF CONNECTIVE TISSUES EMBRYONIC CONNECTIVE TISSUE Mesenchyme Mucous (Wharton’s jelly) CONNECTIVE TISSUE PROPER Loose (Areolar) Dense - Irregular - Regular SPECIALIZED CONNECTIVE TISSUE Adipose (unilocular & multilocular) Reticular Cartilage Bone Blood

27. DENSE CONNECTIVE TISSUE DENSE IRREGULAR CONNECTIVE TISSUE is characterized by an abundance of fibers and few cells. It forms the reticular or deep layer of the dermis DENSE REGULAR CONNECTIVE TISSUE is characterized by ordered and densely packed arrays of fibers and cells. It is the main functional component of tendons, ligaments, aponevroses

29. L.M. of a tendon, cross section