5- Connective Tissue I 241 updated_9a50d53a17a41df5c557c0a2ed193341.pptx

Connective Tissue I Anatomy Unit  Objectives What is connective tissue Types of connective tissues Functions of connective tissues – Relation of structure and function  The Connective Def: The CT supports, binds and separates various...

Connective Tissue I Anatomy Unit  Objectives What is connective tissue Types of connective tissues Functions of connective tissues – Relation of structure and function  The Connective Def: The CT supports, binds and separates various tissues and organs tissue Types: Connective tissue proper (True)  Loose connective tissue  Dense connective tissue Special types CT 1. Cartilage (Supportive) 2. Bone (Supportive) 3. Blood and Hematopoietic tissue 4. Lymphoid tissue.  Connective tissue proper Formed of:  Cells  Fibers  Matrix (Ground substance). Types Of Connective Tissue Fibers: 1. White collagenous fibers 2. Yellow elastic fibers 3. Reticular fibers  1- White collagenous fibers Characters White, Strong, resist stretch Forms wavy bundles Types & Sites Of Collagen:  Type I collagen: The most common type Site: Bone, Tendon, Teeth, Dermis of skin  Type II collagen Site: Hyaline & elastic cartilage.  Type III collagen Sites: Liver – Spleen – Kidney –Lymph nodes  Type IV collagen Site: Basal lamina of basement membrane.  Type V collagen Site: Basal lamina of placenta  2- Yellow elastic fibers Characteristics Yellow, Thin, long, highly refractile Elastic. Sites Wall of arteries Trachea - Bronchi – Bronchioles Marfan syndrome: Patients with deficiency in deposition of elastin develop aortic swellings called aneurysms (A life –threatening condition)  3- Reticular (Argyrophilic) fibers Characteristics Reticular (network) Argyrophilic (affinity to Silver). Sites e.g. Liver – Spleen – Lymph nodes.  C.T. Matrix (Ground substance) Composed of: 1. Amorphous component: Glycosaminoglycans Glycoproteins 2. Fibrous component. 3. Tissue fluid.  Amorphous component Glycosaminoglycans (GAGs)- Non-sulfated type (Hyaluronic acid) Soft jelly like Sites: Wharton's jelly of the umbilical cord Synovial fluid  Amorphous component Glycosaminoglycans (GAGs) - Sulphated type (Chondroitin sulfate) Hard Sites: cartilage and bone.  Amorphous component Glycoproteins Act as adhesive materials. Examples: Cartilage, bone, C.T. proper  A-Fixed (Resident) C. T. cells: Undifferentiated Mesenchymal Cells (UMCs). Fibroblasts and Fibrocytes. Connective Adipocytes = Fat cells. Reticular cells. Tissue Fixed Macrophages (Histiocytes) b- Free (Wandering) cells: Cells Plasma cells. Mast cells. Melanocyte = Pigment cells Wandering (Free) macrophages. WBCs → Migrated Blood leucocytes.  1. Undifferentiated Mesenchymal Cell Origin:Mesodermal cells of the embryo Site: in pulp of deciduous teeth. It acts as a multipotent stem (mother) cell  2. Fibroblast Myofibroblast develop from pericytes (Branched cells around blood capillaries). The most common type of C.T. cells. Very numerous in the loose C.T. Responsible for growth of C.T. and healing of wounds (synthesis and secretion of ECM)  3. Macrophage Origin: blood monocytes Mainly in loose CT, A) M1 "Killer" macrophages: Phagocytic function B) M2 "Repair" macrophages: wound healing and tissue repair.  4. Reticular cell The commonest cell in reticular CT. It is a special type of fibroblast synthesizing collagen III. Functions: 1. Supportive function 2. Phagocytic function  5. Adipocyte Brown adipocyte (Multilocular) abundant in Neonates & children In adults : Kidneys ,Adrenal glands, Aorta & mediastinum. Contains many fat droplets  5. Adipocyte White adipocyte (unilocular) Around organs, subcutaneous layer, yellow marrow of long bone. 10-times larger than brown adipocyte Contains a large fat globule (signet ring)  6. Plasma cells Origin: Activation of B-lymphocytes (Originating from UMCs) Site: Lymphoid organs – Pleura – Peritoneum Number: Increases at sites of Chronic inflammation Nucleus: Rounded, Eccentric-Cart-wheel in shape Function: Secretion of antibodies (Responsible for humoral immunity) 6. MAST cells Origin: UMCs Site: Arrange in groups around blood vessels in loose CT of respiratory and digestive tracts Number: Increases in allergy Function:  Secretion of Heparin: Natural anticoagulant  Synthesis, Storage & Secretion of Histamine: InAllergy and Inflammation.