Histo

• Connective tissue


  Consists of cells and extracellular material called matrix, which consists of fibers, ground substance, and tissue fluid

  
• Connective tissue


  • Binds, anchors and supports various tissue organs and body parts

  
• Functions of connective tissue


  • Hold together structures like skin, muscle, blood vessels etc. and form a framework that supports the cellular elements of various organs like spleen, lymph node and glands
  • The looseness of areolar tissue facilitates movement between structures connected by it
  • Tendons transmit the pull of muscle to their insertion
  • Ligaments hold the bone ends together at joints
  • Forming a site for storage of fat
  • Defense and protection against invading foreign substances (e.g. bacteria)
  • Helping in wound repair
• Connective tissue cells


  • Fibroblasts
  • Adipose (fat) cells
  • Macrophages or histocytes
  • Mast cells
  • Plasma cells
  • Leukocytes
• Collagen fibers


  Tough, fibrous protein that are thick and do not branch, the most abundant fibers of most connective tissue
• Elastic fibers


  Thin and small that branch, have less tensile strength than collagen fibers, found in the lungs, bladder, skin, and wall of aorta
• Reticular fibers


  Thin and form a delicate netlike framework in the liver, lymph node, spleen and other where the filter blood and lymph
• Ground substance


  A complex mixture of glucoproteins and proteoglycans that participate in binding cells to the fibers of connective tissue, is colorless and transparent, fills the space between cells and fibers, is viscous and acts as both a lubricant and a barrier to the penetration of invaders
• Types of connective tissue


  • Loose connective tissue (Adipose, Areolar, Reticular, Mucous, Mesenchyma)
  • Dense connective tissue (Regular, Irregular)

  
• Loose connective tissue


  • More prevalent, characterized by a loose, irregular arrangement of its connective tissue fibers and abundant ground substance (numerous connective tissue cells in its matrix), collagen fibers, fibroblast, and macrophages predominate
• Adipose tissue


  Cells adapted for the storage of fat, found in isolation or in clumps throughout loose supporting tissues or may constitute the main cell type, acts as a temporary store of substrate for the energy–deriving processes of almost all tissues, has a rich blood supply
• Types of adipose tissue


  • White adipose tissue (important energy store, acts as a thermal insulator under the skin, functions as a cushion against mechanical shock)
  • Brown adipose tissue (highly specialized, found in new born mammals and some hibernating animals, plays an important part in body temperature regulation)
• Areolar tissue


  • Characterized by abundant ground substance housing the fixed connective tissue cells: fibroblasts, adipose cells, macrophages, and mast cells as well as some undifferentiated cells, also scattered throughout the ground substance are loosely collagen, reticular and elastic fibers, small nerve fibers as well as blood vessels that supply the cells with oxygen and nutrients, fills the space between groups of muscle cells, supports the epithelial tissue, and forms a layer that sheathes the lymphatic and blood vessels
• Mucous tissue


  Has abundant ground substances, a jelly-like tissue containing very few fibers, the cells in this tissue are mainly fibroblasts, the principle component of the umbilical cord
• Mesenchyme tissue


  Made up of small cells with slender branching processes that join to form a fine network, embryonic connective tissue that consists the tissue of the embryo
• Reticular tissue


  A specialized loose connective that provides the architectural framework of bone marrow, liver, spleen, lymph node, smooth muscle and gland and the islets of Langerhans, made up of reticular fibers and fiber form supporting network for the cells

  
• Dense connective tissue


  • Contains thicker and densely packed collagen fibers (fewer cells-types and less ground substance), irregular dense connective tissue exhibits a random and irregular orientation of its collagen fibers, regular dense connective tissue exhibits densely packed collagen fibers with regular and parallel arrangement