Epithelium 2009 by xiaopangnv

VIEWS: 9 PAGES: 44

									      Epithelium
      Michael Hall PhD


University of California
     Los Angeles
    Features common to all epithelia
1.The cells are closely packed together
2.The cells are polarized
3.The apex always faces an open space
4.The base always sits on a basement membrane
Epithelial cells are closely packed
Epithelial cells always have a free surface
    and sit on a basement membrane
       Free Surface




          Lamina propria
    Epithelium
     Basement
     membrane




Note that both of the
epithelia face a free surface



     Basement
     membrane
     Epithelium
 Types of
Epithelium

 Simple
One cell layer



Stratified
 More than
one cell layer
   Types of
  Epithelium

1. Simple
   squamous
2. Simple cuboidal
3. Simple columnar


4. Stratified squamous
5. Stratified cuboidal
6. Stratified columnar


7. Pseudostratified
Simple squamous epithelium
                       Free space

   Basement membrane




   Connective tissue
Simple squamous epithelium (endothelium)
          lining an arteriole




              endothelium
Simple cuboidal epithelium (kidney)




         Basement membranes




          Free surface
Simple epithelia in kidney medulla


         scu


                           ssq

  scu*               ssq
         ssq   scu
                                 scu
Simple columnar epithelium (duodenum)
Stratified Squamous Epithelium (cornea)
       free surface




               bm

                ct
Stratified Squamous Epithelium
           free surface
                          squamous cells




 basement membrane
        Stratified Cuboidal Epithelium
Connective tissue




          Duct of sweat gland
                                Basement membrane
Stratified Columnar Epithelium (urethra)


                                    lp


                                         bm
             Columnar cells
Pseudostratified
  Epithelium
Pseudostratified Columnar Epithelium
              (duodenum)




           Basement Membrane   Basal cells
Transitional Epithelium
     (Urinary system)
                         Transitional
                         Epithelium
                         (relaxed -top layer
                         of cells is cuboidal)

    basement membrane



                        Transitional
                        Epithelium
                        (stretched-top layer
basement membrane       of cells is squamous)
              Mesothelium




Mesothelium is the name given to the simple squamous
 epithelium that lines the closed cavities of the body




  endothelium                   Endothelium
Basement membranes
Simple squamous epithelium


 Basement membrane




 Connective tissue
Basement Membrane of epithelium
Molecular structure of extracellular matrix
forming the basement membrane




                 Inside of cell
Junctional Complexes
‘Terminal Bars’ between epithelial cells
Epithelial
                      Z. occludens
Junctional
                      Z. adherens
 Complex
             Cell 1        Cell 2



                      Desmosome
 Components of the          1
Epithelial Junctional
     Complex
                            2

  1. Z. occludens
  2. Z. adherens
  3. Macula                     3
     adherens
     (desmosome)
  4. Gap junction
  5. Hemidesmosome          4
                        5
               Cell 1   Cell 2


Generalized
Structure of
a Junctional
Complex
 Connexon 1                  Connexon 2

              Gap Junction

< 1,500 Da

                               > 1,500 Da
Surface Specializations of
     Epithelial Cells
Villin

Actin      Structure of a
           microvillus
Fimbrin

Myosin
Spectrin
Stereocilia in the Epididymis




            Stereocilia
Cilia in the Respiratory Mucosa

       Cilia
    cilia

microvilli
Components of a Mucosa




               Basement membrane

 Mucosa
The End




Whoopee !!

								
To top