Types of tissues

• Epithelial tissue


  Also referred to as epithelium, this tissue has a free surface facing a body fluid or the outside environment and provides a covering or lining
• Epithelial tissue


  • Cells are compactly packed with little intercellular matrix
  • Two types: simple epithelium and compound epithelium
• Simple epithelium


  Composed of a single layer of cells and functions as a lining for body cavities, ducts, and tubes
• Compound epithelium


  Consists of two or more cell layers and has a protective function
• Types of simple epithelium


  • Squamous
  • Cuboidal
  • Columnar
  • Psuedostratified
• Squamous epithelium


  • Found in walls of blood vessels and air sacs of lungs, involved in forming a diffusion boundary
• Cuboidal epithelium


  • Found in ducts of glands and tubular parts of nephrons in kidneys, functions in secretion and absorption
• Columnar epithelium


  • Found in lining of stomach and intestine, functions in secretion and absorption
• Ciliated epithelium


  Columnar or cuboidal cells bearing cilia on their free surface, function to move particles or mucus in a specific direction
• Glandular epithelium


  Columnar or cuboidal cells specialised for secretion, can be unicellular (goblet cells) or multicellular (salivary gland)
• Types of glands


  • Exocrine (secrete through ducts)
  • Endocrine (secrete hormones directly into fluid)
• Compound epithelium


  Made of more than one layer of cells, main function is to provide protection against chemical and mechanical stresses
• Cell junctions in epithelium


  • Tight junctions (stop substances from leaking)
  • Adhering junctions (keep cells together)
  • Gap junctions (allow communication between cells)
• Connective tissue


  Most abundant and widely distributed in the body, function is to link and support other tissues/organs
• Types of connective tissue


  • Loose
  • Dense
  • Specialised
• Loose connective tissue


  • Areolar tissue (beneath skin)
  • Adipose tissue (fat storage)
• Dense connective tissue


  • Dense regular (tendons, ligaments)
  • Dense irregular (skin)
• Specialised connective tissue


  • Cartilage
  • Bone
  • Blood
• Cartilage


  Solid and pliable intercellular material, resists compression, cells (chondrocytes) enclosed in small cavities
• Bone

  Hard and non-pliable ground substance rich in calcium salts and collagen, provides structural frame, contains bone cells (osteocytes)
• Blood


  Fluid connective tissue containing plasma, red blood cells, white blood cells, and platelets, transports various substances
• Muscle tissue


  Made of long, cylindrical fibres that contract and relax to cause body movements, three types: skeletal, smooth, and cardiac
• Skeletal muscle


  • Striated muscle fibres bundled in parallel, attached to skeletal bones
• Smooth muscle


  • Fusiform fibres without striations, found in walls of internal organs
• Cardiac muscle


  • Contractile tissue present only in the heart, cells fused together with communication junctions
• Neural tissue


  Exerts greatest control over body's responsiveness, composed of neurons (excitable cells) and neuroglia (support cells)