Epithelial tissue

  • Epithelial tissues covers the body surface and organs, forms the inner lining of body cavities, lines hollow organs and compose glands

  • Apical surface is the surface exposed to the outside or internally to an open space

  • Basal bottom end is made of a thin extracellular layer called the basement membrane that anchors the epithelium to underlying connective tissues

  • Epithelial tissue lacks blood vessels

  • Epithelial cells readily divide so injuries heal quickly as new cells replace lost or damaged cells

  • Epithelial skin cells are packed together tightly with little to no extracellular matrix

  • Epithelial tissues are classified by cell shape and number of cell layers

  • Squamous epithelium are thin flattened cells

  • Cuboidal epithelium are cube shaped cells

  • Columnar epithelium are elongated that are taller than they are wide

  • Simple epithelial tissues have one layer of cells

  • Cells of simple epithelial tissue are all attached to the basement membrane and also reach the free surface

  • Simple epithelial tissues function well for absorption, diffusion and filtration

  • Stratified epithelial tissues are made of two or more layers of cells

  • In stratified epithelial tissues only one layer is anchored to the basement membrane and only one layer reaches the free surface

  • Stratified epithelial tissues serve well for protection and composition of glands

  • Simple squamous epithelium single layer of thin flattened cells

  • Simple squamous epithelium allow substances to easily pass through

  • Simple squamous epithelium is common at cites of diffusion and filtration

  • Simple squamous epithelium lines air sacs of the lungs, forms capillary walls, lines insides of blood and lymph vessels , lines body cavities and cover viscera

  • Simple squamous cells are easily damaged because they are very thin

  • Simple cuboidal epithelium is a single layer of cube-shaped cells

  • Simple cuboidal epithelium lines follicles of the thyroid gland, covers the ovaries and lines most of the kidney tubules and ducts of certain glands

  • Simple columnar epithelium has a single layer of cells longer than they are wide

  • Nonciliated simple columnar epithelium lines the uterus and parts of the digestive tract including the stomach and intestines

  • Simple columnar epithelium protects underlying tissues and secrete digestive fluids and absorb nutrients from digested food

  • Pseudostratified columnar epithelium is a single layer of elongated and variously shaped cells

  • Pseudostratified columnar epithelium functions are protection, secretion, movement of mucus and substances

  • Location of Pseudostratified columnar epithelium tissues are the linings of respiratory passages

  • Stratified squamous epithelium has many layers with top cells flattened

  • Stratified squamous epithelium is protection

  • Stratified squamous epithelium is found at the superficial layer of skin and linings of oral cavity, vagina and anal canal

  • Stratified cuboidal epithelium consist of 2 or 3 layers of cube shaped cells

  • Stratified cuboidal epithelium is for protection

  • Stratified cuboidal epithelium is located in the lining of ducts of mammary glands, sweat glands, salivary glands and pancreas

  • Stratified columnar epithelium is made up of a top layer of elongated cells lower layers of cube-shaped cells

  • Stratified columnar epithelium is for protection and secretion

  • Stratified columnar epithelium is located in part of the male urethra and lining of larger ducts of excretory glands

  • Transitional epithelium is made of many layers of cube-shaped and elongated cells

  • Transitional epithelium is for stretchability and protection

  • Transitional epithelium is located in the inner lining of the urinary bladder and linings or ureters and part of the urethra