part 2

• Types of Epithelial tissues

  • Covering Epithelia
  • Glandular Epithelia
• Covering Epithelia


  • Outer
  • Inner
• Glandular Epithelia


  • Exocrine
  • Endocrine
• Covering and lining epithelia

  • Classified according to the arrangement of cells and the shapes of the cells
• Arrangement of cells


  • Simple
  • Stratified
  • Psuedostratified
• Simple epithelium


  Single layer (important and useful for secretion; absorption; filtration)
• Stratified epithelium


  Two or more layers (protective)
• Psuedostratified epithelium


  Appears to have multiple layers, but it doesn't. It's a single layer. The cells all touch the basement membrane even though it may not seem like it. Not all cells reach the apical surface. So basically, it's a simple epithelium that looks like a more stratified one.
• Cell shapes


  • Squamous
  • Cuboidal
  • Columnar
  • Transitional
• Squamous epithelium


  Flat and thin (helps allow passage for diffusion)
• Cuboidal epithelium


  About as tall as they are wide (important and useful for secretion; absorption)
• Columnar epithelium


  Cells that look taller than they do wide. With this shape, there is often a lot of space between the nucleus and the membrane.
• Transitional epithelium


  A stratified epithelium in which the cells can change shape from cuboidal to flat shape depending on organ shape. Eg:- allow to stretch (organs like the urinary bladder)
• Simple squamous epithelium


  • Delicate
  • Filtration (kidney), diffusion (lung), secretion where slippery surface needed
  • Thin and flat
  • Cells are like fried eggs or paving stones
• Mesothelium


  Lines the pericardial, plural, peritoneal cavities. Pericardial is a sack where heart beat. Pleural is where lungs expand and contract. There is a layer where there is fluid to help lubricate and slide, that is where mesothelium is found.
• Endothelium


  Lines inside of our heart and the blood and lymphatic system
• Serosa


  Outer membrane layer of all the surfaces and internal organs. Lines body cavity and viscera. Comprises mesothelium and connective tissue.