epithelia

Examples of epithelia in the following topics:

• Epithelial Tissues

  • The types of epithelia are classified by the shapes of cells present and the number of layers of cells.
  • Epithelia composed of a single layer of cells is called simple epithelia; epithelial tissue composed of multiple layers is called stratified epithelia.
  • This is called pseudostratified, columnar epithelia .
  • Squamous epithelia cells (a) have a slightly-irregular shape and a small, centrally-located nucleus.
  • Pseudostratified columnar epithelia line the respiratory tract.

• Glandular Epithelia

  • Epithelia can also be organized into clusters of cells that function as exocrine and endocrine glands.

• Types of Epithelial Tissue

  • Stratified epithelia are more durable and protection is one their major functions.
  • Stratified epithelia can be columnar, cuboidal, or squamous type.
  • In keratinized epithelia, the most apical layers (exterior) of cells are dead and lose their nucleus and cytoplasm.
  • Transitional epithelia are found in tissues that stretch and it can appear to be stratified cuboidal when the tissue is not stretched, or stratified squamous when the organ is distended and the tissue stretches.

• Dendritic Cells

  • Dendritic cells are present in lymphoid organs, the epithelia of the skin, the gastrointestinal and respiratory tracts, and in most parenchymal organs.
  • Langerhans cells of the epidermis) are located in main portals of entry of microbes (skin and gut epithelia).

• Tight Junctions

  • Tight junctions are located within our body’s epithelia. 
  • Epithelia is the plural of epithelium. 

• Gastrulation

  • Following gastrulation, cells in the body are either organized into sheets of connected cells (as in epithelia), or as a mesh of isolated cells, such as mesenchyme.

• Characteristics of Epithelial Tissue

  • Epithelia tissue forms boundaries between different environments, and nearly all substances must pass through the epithelium.

• Desmosomes

  • They are common in numerous epithelia including the skin and are also found in muscle tissue where they bind muscle cells to one another.

• Female Duct System

  • The fallopian tubes, also known as oviducts, uterine tubes, and salpinges (singular salpinx) are two very fine tubes lined with ciliated epithelia, leading from the ovaries of female mammals into the uterus, via the utero-tubal junction.

• Malaria

  • This false-colored electron micrograph shows a sporozoite migrating through the cytoplasm of midgut epithelia.