Lecture 11 Connective Tissue Proper (Part 2) PDF

HNU Faculty of Medicine Histology & Cell Biology Department Year 1 Principle of Human Body Structure HBS-101 Lecture 11 Connective Tissue Proper (Part 2)  objectives By the...

HNU Faculty of Medicine Histology & Cell Biology Department Year 1 Principle of Human Body Structure HBS-101 Lecture 11 Connective Tissue Proper (Part 2)  objectives By the end of this lecture the student will be able to: 1. Classify connective tissue types. 2. Describe the histological structure (LM and EM) correlated to functions of UMCs, fibroblasts, pericytes , reticular cells. 3. Clinically correlate between keloid and palmar fibromatosis and the defective structures. Types of connective tissue: According to matrix connective tissue proper Soft Rubbery cartilage Hard Bone Fluid blood. Components of C.T. A. Cells proper B. Fibers C. Extracellular matrix A- C.T CELLS According to stability and life span, 2 types of cells; Fixed (stable, long Free (transient, lived) 1.Mesenchymal cell. short lived) 2.Pericyte. 1.Plasma cell. 3.Fibroblast. 2. Mast cell. 4.Fat cell. 3. Leukocytes. 5.Reticular cell. 4. Free macrophage 6.Fixed macrophage. 7.Pigment cell. A- C.T CELLS According to shape, 2 types of cells; Branched cell Rounded cell 1.Fat cell. 1.Mesenchymal cell. 2.Pericyte. 2.Plasma cell. 3.Fibroblast. 3.. Mast cell. 4.Reticular cell. 3. Leukocytes. 5.Fixed macrophage. 4. Free macrophage 6.Pigment cell.  Fixed (stable, long  Undifferentiated Pericytes Mesenchymal Cells (UMCs) Origi (UMCs) n In young: embryonic Around capillaries. Site mesenchymal tissue. In adult: bone marrow & around B.V(Pericytes) Sha a.LM:*Small branched. a)LM:*Branched with long pe *Pale basophilic cytoplasm. processes *Central large oval pale nucleus. *Pale basophilic cytoplasm. b.EM: *Central large oval pale nucleus. Many ribosornes but few other b)EM:*Few organelles. organelles. Can differentiate to; In case of injury, *Can differentiate Fun a) Other types of CT cells. into smooth M., endothelial cells& ctio b) Blood cells. c) Smooth muscle fibres fibroblasts. *& By contraction🡪 n d) Endothelial cells. vasoconstnction.  Fibroblasts origin (UMCs)& Pericytes Site Most common type in connective tissue. Shap Active fibroblasts Inactive(Fibrocytes) e a)LM: Stellate with many long processes. a)LM: Deeply basophilic cytoplasm. Spindle with few Large oval pale nucleus with prominent processes. nucleolus. Pale basophilic cytoplasm. Small dark nucleus. 1Synthesis of C.T. fibers. Change to Active in healing Func 2.Synthesis of C.T.matrix, of wounds. tion 3.Production of growth factors that influence cell growth and differentiation. 4.Divide in wound heating  Reticular Cells Pigment cells Origin UMC C.T. macrophages Site Stroma of glands & spleen & Dermis in skin & pigmented lymph nodes. layer of eye Shap a-LM: Small Stellate a-LM; e with many long thin processes. Small branched. Pale basophilic cytoplasm. Granular cytoplasm. Central rounded pale Central rounded nucleus. nucleus+ prominent nucleolus. Funct a. Synthesis of reticular F. Carry melanin to ion b. Change to phagocytic cells. 1)Give color of skin and c. Antigen presenting cell to eye. activate lymphocytes. 2) Protect skin from  Adipose Cells (Fat cells /adipocytes) Origin UMC that accumulate lipids🡪lipoblast🡪adipocyte Site Unilocular adipose cell Multilocular adipose cell White adipose CT Brown adipose CT Shap a-LM: Large, oval 50-150 a-LM; Smaller. e Store fat in the form of one large Fat present as small droplets. droplet. No signet ring. lipid droplets are removed during Nucleus;spherical & central, staining byHX & E each cell have signet Pigmented by the cytochrome ring appearance pigments in mitochondria. Eccentric& flattened nucleus. b-EM: Less free ribosomes. Can be stained by Sudan III (orange). Many spherical mitochondria. b-EM: More free ribosomes. Few filamentous mitochondria. Func *Synthesis and storage of fat to be Breakdown of fat to release tion used in support, heat. heat insulation.  Macrophage(Free & Fixed) Origin Monocytes Connective tissue (Fixed calledhistiocytic), Site Lymphoid tissue, bone marrow, brain,liver,lung.(Free) LM:Large branched with pseudopodia, Pale basophilic cytoplasm. Shap Single dark eccentric kidney shaped nucleus e Specific stains: trypan blue or India ink b. EM: Rich in lysosomes, phagocytosed particles residual bodies. Phagocytosis of &microorganisms. Form multinucleated giant cell. Func Antigen presenting cell to activate B-lymphocytes to form tion antibodies. produce enzymes (e.g.collagenase) & cytokines important in defense & repair. Connective Tissue Proper Function Site TYPES Support. Under epithelium; 1)Loose subserous , dermis of (Areolar) epithelium, blood C. T.: skin, submucosa. vessels and Around blood vessels.nerves Fills spaces between other tissues. Support cells in in the stroma of; 2)Reticular Lymphatic organs as C. T.:. its sites spleen and lymph nodes. Bone marrow. Glands as liver. Protects nearby Umbilical cord. 3)Mucoid C. T.: struc­tures from Pulp Of growing tooth..pressure Vitreous humor of eye.  Structure TYPES. 1)Loose (Areolar) C. T.: 2)Reticular C. T.: 3)Mucoid C. T.:  Function Site Structure TYPES Brown White Brown White Large number of fat (unilocular cells forming lobules 4)A ) separated by C.T septa of dip collagen & elastic fibres. Heat 1. A) foetus & 1.Under Brown White F ose generatio Synthesi new born: skin. n. s& 1.Interscap 2.Around (multilocular) (unilocular) a t C.T; storage ular kidney and Small. Many Large. c of fat. 2. Axiila. blood droplets of One e.2 3.Mediastin vessels. lipids. Many droplet of l Support um. 3. mitochondria. lipid. l of kidney B)In adults: Mesentery. Spherical Few s.& B.V only around central! mitochondr Heat.3 thoracic A. nucleus..ia.insulator Brown due to: Flat #Rich in blood peripheral.vessels.nucleus Cells are rich in# mitochondria full of cytochrome.pigment Structure TYPE Brown (multilocular) White (unilocular) 4)A dip ose C.T; Functi Site Structure TYPES on Irregular Regular 5) SUP Periosteum, Tendons Irregular Regular White fibrou PO perichondriu m.. Collagen.Cornea bundles are Collagen bundles are s RT.Sclera irregularly parallel to arranged with each other conne fibroblasts in- and to between fibroblasts ctive in-between tissue: gives Aorta and large vessels. 6)Yellow flexible elastic Support. Bronchi and C.T bronchioles. Ligamentum nuchae & ligamentum flavum Structure TYPES Irregular Regular 5) White fibrous connective tissue: 6)Yellow elastic connective tissue Reference Junqueira's Basic Histology Text and Atlas, 17th edition by Anthony Mescher 22