L2.1: Epithelial Tissue

• • Groups of cells that are similar in structure and function.
  • There are four primary types of tissues.
  • Epithelial (covering)
  • Connective (support)
  • Muscle (movement)
  • Nervous (control)
  • The arrangement of the tissues determines each organ’s structure and what it is able to do.


  Tissue
• • Epithe: laid on or covering; therefore, it’s the lining, covering, and glandular tissue of the body.
  • Covers all free body surfaces, both inside and out. forms the boundaries that separate us from the outside world.
  • Where can we find epithelia?
  • Bladder – transitional
  • Kidneys – cuboidal
  • Stomach – simple columnar
  • Trachea – pseudostratified columnar
  • Skin – stratified squamous
  • They can be find either in the :
  • outer surface of the organ;
  • example: ovaries
  • inner lining of the organ.
  • The border between the inside and the outside.

  Epithelial tissues
• • Lining, covering, and glandular tissue of the body.
  • Superficial: no bleeding (no blood, no blood vessels harmed).
  • Covers all free body surfaces (both inside and out).
  • Contains versatile cells.
  • Forms boundaries that separate us from the outside world.
  • All substances that the body gives off and receives must pass through epithelium.
  • Fit closely together to form continuous sheets.


  Epithelial tissues
• locations of epithelial tissues

  • body coverings
  • body linings
  • glandular tissue
• functions of epithelial tissues

  • protection
  • absorption
  • filtration
  • secretion
  • diffusion
• Skin epithelium provides protection against bacterial and chemical damage.


  protection
• • Epithelium in the stomach and small intestines which absorbs nutrients from food into the body.
  • Simple columnar epithelia – gastrointestinal tract


  absorption
• • The kidneys’ epithelium both absorbs and filters.
  • Removal of toxins from the blood in the form of urine.
  • Waste: Uric acid, CO2, toxic things for the body, nitrogenous waste.


  filtration
• Glandular epithelium forms various glands that secretes sweat, oil, digestive enzymes, and mucus.


  secretion
• gas exchanges in the lungs


  diffusion