back  

Lining epithelia

 

Epithelia

Epithelia will be discussed according to the following scheme:
Type Number of layers Shape Line drawing
Covering and Lining epithelium Simple Squamous
Cuboidal
Columnar
Pseudostratified
Stratified Squamous
Cuboidal
Columnar
Urothelium (transitional)

Type Function Cells Arrangement Shape Example
Glandular epithelium Exocrine Unicellular
Multicellular Simple tubular
alveolar
Compound tubular
tubulo-alveolar
alveolar
Endocrine Unicellular
Multicellular Cords
Islets
Acini
Follicles

You should be able to:

  • Describe the basement membrane and its components.
  • Classify epithelial tissue, using cell shape, stratification and surface specialisations.
  • Recognise covering, lining and glandular epithelial.
  • Distinguish between and classify exocrine and endocrine glands and unicellular and multi-cellular glands.
  • Give examples of and explain the structure, function and location of epithelial tissue.
Each specimen must be studied as follows:
  1. General structure
    • The number of cell layers, i.e. squamous or stratified.
    • The differences in size and shape of these cells i.e. squamous, cuboidal, columnar etc.
    • Cell borders visible or not.
    • Position of the cells in relation to each other and the underlying basal lamina.
    • Nature of the free or luminal surface e.g. ciliated, brush border etc.
    • Presence of glands and hair.
    • Types of glands present e.g. single cell, simple, tubular etc.
  2. Cell structure
    • Nucleus
      • Staining reaction and degree of granularity of chromatin.
      • Position in the cell.
      • Shape and size.
      • Shape and size in comparison to the shape and size of the cell.
    • Cytoplasm
      • General appearance and texture.
      • Staining reaction.
      • Presence of inclusions such as prominent granules, vacuoles, pigments etc.

Slides for this week

For each slide, complete the work as listed below. At this time, your focus should be on the specific epithelium. Completing the whole slide will assist you in understanding and retention. For each slide, allocate an A3 spread in your workbook. Remember to add the slide and its page number to the index in the front of the book.

Tasks

Study the slides listed above, using the structured approach described on the page of each slide.

Calibration

  1. Name the 3 main cell groups, according to shape.
  2. What is the difference between stratified and pseudostratified epithelium?
  3. Name and define the 4 types of epithelial secretion.
  4. Name an example of tumours of epithelial cells.
  5. Name an example of tumours of glandular epithelial cells.

© julie 2020 marius loots