MBBS and BDS Course

These epithelia consist of two or more layers of cells. In which only the bottom layer rests on the basement membrane. Stratified epithelia are further classified into subtypes according to the shape of the cells in the superficial layer. The layer on the free surface of the epithelium. Stratified Epithelia This group of epithelia has the following types. stratified squamous epithelium stratified cuboidal epithelium stratified columnar epithelium A special type of the stratified epithelia is called transitional epithelium.

Simple Columnar Epithelium This type of epithelium consists of a single layer of columnar (column-shaped cells). On surface view the cells appear as a mosaic resembling that of simple cuboidal epithelium but the outline of the cells is rather smaller. In pendicular sections the columnar shape of the cells becomes evident in which it is seen that the height of each cell is much greater than its width. The nucleus is commonly oval in shape and usually located near the base of the cell. The nuclei of all the cells of a sheet of simple columnar epithelium are often seen to be situated at roughly at the same level. Simple columnar epithelium is widely distributed in the body. Simple Columnar Epithelium   It lines (for example) :  the internal surface of  Stomach  Intestines  Gallbladder  Uterus  In many locations in the body  The cells of the simple columnar epithelium show modifications on their apical surface, which includes m...

Simple Cuboidal Epithelium                   This variety of epithelium also consists of a single layer of closely-packed cells. In sections made perpendicular to the epithelial sheet. The cells give a roughly square outline, the height and width of each cell appearing to be nearly equal. This appearance is the reason why this variety of epithelium was titled in earlier times as cuboidal epithelium. The surface view of the epithelium reveals that the cells are rather hexagonal or polygonal in shape. The closely fitting cells appearing to form a mosaic. Each cell contains a spherical nucleus which is located in the center of the cell. The simple cuboidal epithelium has a restricted distribution in the body. Simple Cuboidal Epithelium  Examples  (i) The epithelium lining the follicles of the thyroid Gland.  (ii) The epithelium lining the distal convoluted tubules of the kidneys. Found In :  Glands T...

                The simple squamous epi variety of epithelium consists of a single layer of thin flat cells which are roughly polygonal in outline. The free surface of each flat cell faces a cavity or the lumen of a tubular structure, while the basal surface rests on a basement membrane, The cells have serrated or wavy margins and the adjacent cells fit closely together to form a continuous sheet. Each cell contains a flattened nucleus located in the center of the cell. Presence of the nucleus in the central region of the flat cell causes the plasma membranes above and below to bulge slightly. Simple squamous epithelium                 On surface view the closely fitting polygonal cells appear like a mosaic. Sections made perpendicular to the epithelial sheet show that in profile (ie, in side view) the individual cells give fusiform (spindle-shaped) appearance because the central region of each cel...

 These epithelia, also called unilaminar epithelia, consist of only a single layer of cells. Each cell of this epithelial layer has a basal surface which rests on the basement membrane, and a free surface which faces the cavity (or lumen) of an organ' or a body part. Simple Epithelia A simple epithelium consists of only a single layer of cells. Each cell has a free surface and a basal surface which rests on the basement membrane. The lateral margins of the adjacent cells are closely apposed and are held together by cell junctions; therefore, in a surface view, the cells appear to form a mosaic. According to the shape of their component cells, the simple epithelia are further classified into the following three types:

  Histology   Embryology   Neuroanatomy   Gross anatomy =================================                  HISTOLOGY CELL: The  cell  is the basic structural and functional unit of all living organisms. Cells vary widely in size and shape depending on their function. Microscopes are used to study cells because most cannot be seen with an unaided eye. TISSUE: 1.Epithelium Tissue:                                 Classification                                                       1. Simple Epithelium                                         Simple squamous epi   Simple cuboidal...