Histology

• What is the first level of structural complexity in histology?


  Chemical level- atoms combine to form molecules
• What are the characteristics of epithelial tissue?


  • Cellularity
  • Cell contacts
  • Polarity
  • Basement membrane
  • Avascularity
  • Regeneration
• What does the term 'cellularity' refer to in epithelial characteristics?

  Scarcity or abundance of cells
• How are epithelial cells joined together?

  By special cell junctions forming sheets
• What does 'polarity' in epithelial cells refer to?


  Orientation of the cell in a specific way
• What is the basement membrane made of?


  Glycoproteins
• What is the function of the basement membrane?


  Allows specific substances through selectively
• What does 'avascularity' mean in epithelial tissue?


  Without blood vessels
• Why is regeneration important in epithelial tissue?

  Cells multiply to replace old cells
• What are the specializations of the apical side of epithelial tissue?


  • Microvilli
  • Cilia
  • Keratinisation
• What are microvilli?

  Folding of plasma membrane, non-mobile
• What are cilia ?

  unequal, mobile, move in unison
• What is keratinisation ?


  Keratin is a protein, present on the outer side of the skin and reduces the loss of water from the skin
• What is histology ?


  The study of tissues which make up the human body.
• What is a tissue ?

  A group of cells that perform a specific function.
• What is the epithelium ?


  Tissue characterised by closely packed cells with little or no extra-cellular material.
• What cell junctions hold together the continuous sheets of epithelium ?

  desmosomes and tight junctions
• What percentage of cancer originate from the epithelium ?

  90%
• Why does 90% of cancer originate from the epithelium ?

  constantly regenerating throughout life
• In what two ways is the epithelium classified ?

  Cell shape

  Number of layers of cells present
• What are the different epithelium shapes ?

  Squamous

  Cuboidal

  Columnar
• What is a squamous epithelium cell ?

  thin and flat
• What is a cuboidal epithelium cell ?

  equal cell height and cell width
• What is a columnar epithelial cell ?

  Shaped like a brick
• What is a simple epithelial cell?


  consists of just one layer of cells
• What is a stratified epithelium cell ?


  two or more layers of cells are present
• What organs are lined by simple squamous epithelium cell?

  Alveoli in the lungs and the inner lining of the blood vessels
• What organs are lined by simple cuboidal epithelium cells ?

  kidney tubules
• What organs are lined by simple columnar epithelium ?

  inner lining of the stomach and the intestine
• What organs are lined by simple columnar ciliates epithelium cells ?

  fallopian tube
• What organs are lined by stratified squamous epithelium cells ?

  mouth, throat and oesophagus
• What organs are lined by stratified squamous keratinised epithelium cells ?

  skin
• What organs are lined by Transitional epithelium cells ?


  Urinary bladder
• What are the different levels of structural complexity ?

  -chemical level

  -celllular level

  -tissue level

  -organ level

  -organ system level
• What is connective tissue ?

  Supporting, binding and packing tissue of the body
• What three components make up connective tissue ?

  cells, fibres and ground substance or matrix
• What are mast cells ?

  Present in clusters around blood cells and contain heparin and histamine
• What is the role of heparin and histamine in mast cells ?

  Heparin is an anti coagulant and histamine causes inflammation making blood vessels porous
• What is the role fibroblasts ?

  Synthesise connective tissue fibres
• what is the role of plasma cells ?

  produce antibodies