Anatomy of General Connective Tissue.pptx

Connective tissue supports, protects, and structures other tissues and organs by binding them together. It's made of cells, fibers (like collagen and elastic), and a gel-like ground substance, and its functions include storing fat, transporting nutrients, and repairing damage. Common types of connective tissue include bone, cartilage, blood, fat, and ligaments

1. General Connective Tissue DR MATHEW JOSEPH MBBS, MD(AIIMS), BCC(Palliative Medicine) Assistant Professor Department of Anatomy Amala Institute of Medical Sciences, Thrissur Visiting Faculty - Buon Ma Thout Medical University, Vietnam SSGP Nodal Officer - Kerala University of Health Sciences

2. As per: Competency based Undergraduate curriculum AN66.1 Describe & identify various types of connective tissue with functional correlation AN66.2 Describe the ultrastructure of connective tissue Medical Council of India, Competency based Undergraduate curriculum for the Indian Medical Graduate, 2018. Vol. 1; pg 1-80.

3. INTRODUCTION Tissue is a group of cell s that are organized to perform a specific function . Consists of cells & extra cellular components Types of tissues Epithelial tissue Connective tissue Muscle tissue Nerve tissue

4. Connective tissue It is characterized by presence of three components Cells Fibers ECM Gives definite shape to organ and body, supports other tissues and performs various functions ( S - F - D - H)

5. Components of Connective tissue

6. Fibers of connective tissue Types of fibers Collagen fibers – all connective tissues Reticular fibers – basement membrane, lymph node, liver Elastic fibers – blood vessels, lung, ligamentum nuchae

7. Collagen Fibers Properties – Strong, flexible, inelastic and have high tensile strength Staining – Eosin, fast green, methylene blue, aniline blue, Masson’s trichrome, van Giesons stain Light microscopy – fibers lies in bundles showing wavy appearance The 29 different types of collagen fibers have 42 different chains α-chains

8. Types of Collagen Fibers Type I commonest (90%) provide protection, resistance to stretch and tension D eficiency – Osteogenesis imperfecta Type II provide resistance to intermittent pressure located in hyaline, elastic cartilage,vitreous of eye, nucleus pulposus of intervertebral disc, notochord D eficiency – Kniest dysplasia

9. Type III (Reticular Fibers) L ocated in loose coonective tissue in liver, spleen, lung, kidney and uterus, endoneurium, blood vessels and skin D efieciency – Ehlers Danlos syndrome Type IV P resent in the form of sheets of short filaments found in lens capsule, glomeruli of kidney, Basal lamina of all epithelia P rovide support to overlying epithelia and filtration barrier of kidney D eficiency – A lports syndrome

10. Reticular fibers Fine fibers mainly composed of type III collagen Located in liver, intestine, lymphatic tissue(except in thymus), glands, nerves, bone marrow and muscles Produced by reticulocytes or fibroblasts Staining – Silver staining (appears black), PAS positive

11. Elastic fibers Fine fibers Located in Skin, Blood vessels, ligamentum nuchae, elastic ligaments of vocal folds of larynx and lung Transmission electron microscopy – it has a central core of amorphous material surrounded by an outer layer of fibrils and the fibers do not show striations Elastin Central core surrounded by Fibrillin I It has glycine allowing coiling and stretching of fibers Desmosine and isodesmosine present in elastin Special stain such as orcein and Verhoeff’s methods are used Deficiency – Marfan syndrome ( abnormal fibrillin gene FBN1 located in chromose 15)

12. Ground substance/ECM Interfibrillar and Intercellular space in the connective tissue is occupied by matrix which allows diffusion of metabolites and provide barrier for micro organism Stains Freeze drying method – metachromatically with toluidine blue PAS positive Composed of GAG : dermatan sulfate, keratan sulfate, hyaluronan ic acid Proteoglycan : aggrecan, syndecan Glycoprotein : fibronectin, laminin

13. GAG L ong chain unbranched polysaccharides H ighly negatively charged because of surface and carboxyl groups H yaluronic acid forms long rigid molecule that provide attachment to proteoglycan molecules and binds with water and converts ECM into gel like substance Proteoglycans C ore protein provides attachment to numerous GAG forming bottle-brush structure Glycoproteins S tabilize ECM E xamples – fibronectin, laminin, entactin, tenascin, osteonectin, chondronectin

14. Cells of Connective tissue Cells are classified into Resident/fixed cells and Wandering cells Fixed cells : fibroblasts, adipose cells, macrophages, mast cells, pericytes Wandering cells : lymphocytes, plasma cells, neutrophils, eosinophils, basophils, monocytes

15. Fibroblasts Most numerous cells forming collagen, elastic or reticular fibers and matrix contains abundant cytoplasm, oval nucleus, branched cytoplasmic processes Fibrocyte is a mature and smaller cell H&E- nuclei visible and thin pale flattened processes visible Most active during wound healing Myofibroblasts Features of both smooth cells and fibroblasts present Elongated spindle shaped cells Contains actin and myosin filaments conferring contractile property Major role in wound healing and tooth eruption Pericytes Present surrounding the endothelium of capillaries and venules Lie in the basal lamina of endothelium Long euchromatic nucleus and several cytoplasmic processes that clasp capillaries

16. Adipocytes synthesize and stores lipids Unilocular adipocytes found in white/yellow adipose tissue functions as insulation and shock absorption special stain – oil red O, sudan black B, Nile blue sulfate method located in cushions around vital organs, mammary pad of fat, orbit, retroperitoneal space, greater omentum Multilocular adipocytes found in brown adipose tissue and mostly found in newborn babies adult – back and neck, scapular region and posterior abdominal wall prevents excessive heat loss and promote thermoregulation in newborns

17. Macrophages/ Histiocytes/ Clasmatocytes Major function is phagocytosis of bacteria, damaged tissue and inorganic particles and as antigen presenting cell 2 types – Fixed and Wandering macrophages Langhans cell – macrophages fuse to form a giant multinucleated cell Mast cells/ Histaminocytes/ Mastocytes Located close to blood vessels Cells are large ovoid with centrally placed nucleus and cytoplasm has basophilic granules which contains heparin & histamine Stain – PAS, toluidine blue, alcian blue Metachromasia – granules look purple to red with toluidine blue IgE present on the cell surface Release histamine, serine proteases, leukotriene C and Histamine

18. Lymphocytes Involved in Immune responses It has deeply staining heterochromatic nucleus and thin im of cytoplasm Grouped as T & B lymphocytes, NK cells Plasma cells/Plasmatocytes Derived from B cell and are ovoid in shape with abundant cytoplasm containing rough endoplasmic reticulum Russel bodies – large immunoglobulin containing inclusions. These are called as Mott’s cells. Russel bodies are PAS positive Produce antibodies Pigment cells Synthesize melanin pigment Located in skin, iris, choroid Derived from neural crest cells Protect from UV lights

19. White blood cell Neutrophil (10–12 μ m) Nucleus: 3–5 lobes Phagocytosis of microorganism Cytoplasm: shows pink or reddish-purple granules Basophils (10–12 μ m) Nucleus: segmented Cytoplasm: dark, basophilic granules Release histamine, promote inflammation (contain histamine) Eosinophil (10–14 μ m) Nucleus: bilobed Phagocytose antigen-antibody complexes, Cytoplasm: dark eosinophilic granules induce allergic reactions, and asthma, attack Parasites Lymphocytes (6–14 μ m) Round nucleus, thin rim of cytoplasm T lymphocytes: cell-mediated immunity B lymphocytes: antibody-mediated immunity NK cells: destroy cancer cells Monocytes (12–20 μ m) Kidney-shaped nucleus Phagocytosis Differentiate into mononuclear phagocytic cells (e.g. macrophages)

20. EMBRYONIC CONNECTIVE TISSUE Mesoderm gives rise to embryonic connective tissue 2 subtypes are Mesenchyme and Mucous connective tissue Mesenchyme Found in embryo consists of mesenchymal cells Space between cells is occupied by ground substance, reticular fibers and collagen fibers Adjacent cells are connected with each other by gap junctions Mucous Connective tissue Present in umbilical cord 2 components – Cells & Wharton’s jelly Cells are spindle shaped with long cytoplasmic processes Wharton’s jelly consists of hyaluronic acid

21. LOOSE CONNECTIVE/AREOLAR TISSUE Widespread connective tissue of the body It has Fibers, Cells, Ground substance Textbook of Human Histology/Yogesh Sontakke/1 st edn/CBS Publishers

22. DENSE CONNECTIVE TISSUE Contains large amount of fibers and less cells and matrix Provides strength and protection 2 types Dense regular and irregular connective tissue Dense Irregular connective tissue Mostly of fibers and small amount of ground substance Cells are mostly fibroblasts Located in Dermis of skin, dura, epineurium, periosteum, etc. , Dense regular connective tissue Contains predominantly of Type I collagen Bundles of collagen fibers show wavy appearance

23. ADIPOSE TISSUE Specialized connective tissue that stores fat Consists od Adipocytes/Fat cells 2 types Yellow/white & Brown adipose tissue

24. Yellow adipose tissue Highly vascular H&E stain – fat gets washed out and cells show empty appearance with thin rim of cytoplasm and peripheral flat nucleus Located in superficial fascia, yellow bone marrow, omentum, mesentry and around viscera Energy storage, insulation and protection of viscera

25. Brown Adipose Tissue Brown in color Smaller than Yellow adipocytes Found in newborn babies and in adult located in back and neck, scapular region and posterior abdominal wall Prevents excessive heat loss Regulate thermogenesis

26. Thank You