Lab 2 Epithelial Tissue: Index - 1)Introduction - 2)Simple Squamous - 3)Simple Cuboidal - 4)Simple Columnar - 5)PsuedoStratified - 6)Transitional - 7)Stratified Squamous - 8)Stratified Columnar - 9)Stratified Cuboidal - 10) Trachea and Esophogus Comparison - 12) Practical

 

BOOK REFERENCES
I)Gartner- CH. 1 II)Ross- Ch. 3,4 III) Wheater Ch. 5 IV)Difiore Ch.1 V) Moran tapes Vol. 3

 

  DON'T Worry About the Organs you are looking at right now. Focus more on the Epithelium. We will Cover the Organs Later

 

 

Introduction to Epithelial Tissue

Epithelial cells form sheets that cover or line the surface of the body. Epithelial cells produce very small quantities of intercellular material and are frequently so closely bound to one another that cell-to-cell junctions are sometimes difficult to recognize. The free (or apical) surfaces of nonglandular epithelial cells display a variety of surface modifications (microvilli, brush border, cilia, or flagella), while the basal or attached surfaces are typically found to rest or sit on what has classically been called a "basement membrane". Epithelial tissue is typically avascular.

Epithelium has a number of important functions: absorption, excretion, lubrication, protection, reproduction, secretion and sensory reception. Note the relationship between structure and function. Primarily, the classification of epithelia is based on :

  1. the shape of the cells in profile (squamous, cuboidal, columnar)
  2. the free surface modification (cilia, microvilli or stereocilia)
  3. the number of cellular layers arranged in the tissue (simple for monolayers or stratified for 2 or more layers).

Thus, if the surface tissue is one layer thick and the shape of the cells making up the tissue is flattened, the tissue is classified as simple squamous epithelium. If the surface tissue is two or more cell layers thick and the cells at the free surface are flattened, then the tissue is classified as stratified squamous epithelium.

Epithelial cells also form the secretory component (parenchyma) of glandular tissue. Connective tissue elements form the glandular stroma.

For this Lab try to understand the location and organization of the cells in epithelia and possible variations in shape before examining examples of the different types.