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Tissues, UNIVERSIDAD DEL VALLE DE MÉXICO TECHNICAL ENGLISH ACTIVITY:…

- - - - Epithelial tissues are identified by both the number of layers and the shape of the cells in the upper layers: simple columnar, pseudostratified epithelium, squamous,cuboidal, Keratinized, columnar
        
        Pseudostratified columnar
        
        Are tissues formed by a single layer of cells that give the appearance of being made from multiple layers, especially when seen in cross section. The nuclei of these epithelial cells are at different levels leading to the illusion of being stratified. However, this tissue is made of a single layer of cells
        
        These tissues can be classified as ciliated or non-ciliated based on a cellular organelle involved with motility and sensory activity.
        This tissue is found in regions where there is a need to secrete mucus to trap foreign bodies and sweep those particles away through the coordinated action of cilia
        
        It´s found in the trachea and much of the upper respiratory tract but is also found in the uterus and fallopian tubes of females, where the cilia propel the ovum to the uterus.
        
        Transitional
        
        is a stratified tissue made of multiple cell layers, where the cells constituting the tissue can change shape depending on the distention in the organ. When the organ is filled with fluid, cells on the topmost layer of this epithelium can stretch and appear flattened. Alternately, they can also appear cuboidal with a rounded shape when the fluid pressure is low.
        
        This epithelium is found lining the urinary bladder, ureters and urethra, as well as in the ducts of the prostrate gland.
        
        One of the primary functions of this tissue is to be an extremely effective permeability barrier, impenetrable to water and most small molecules. The cells of this tissue are probably among the most resistant to osmotic pressure
        
        stratified squamous
        
        non-keratinized stratified squamous
        
        It is a thick epithelium since it is composed of several layers of cells,only the deepest one is in contact with the basal lamina.The basal cells have a cuboidal shape,the cells of the middle part are polymorphic and the cells of the free surface of the epithelium are flattened ,that is ,squamous ,which is why the name of stratified squamous epithelium.
        
        Because the cells on the surface are nucleated ,this epithelium is called non-keratinized.
        
        It is generally moist and lines the mouth ,oral pharynx,esophagus ,true vocal cords and vagina
        
        Keratinized Stratified squamous
        
        Similar to non-keratinized stratified squamous epithelium,the superficial layers of the epithelium are composed of dead cells whose nuclei and cytoplasm have been replaced by keratin
        
        This type of epithelium constitutes the epidermis of the skin
        
        Stratified cube
        
        It generally only has 2 or 3 layers of cubic cells ,it can be located at the level of the ducts of the exocrine glands ,for example the major salivary glands ,it also covers the ducts of the sweat glands.
        
        Its function is not totally clear but it is believed that due to its location it contributes to protection and confers a certain degree of elasticiy
        
        Columnar stratified
        
        It is formed by a deeper ,lowe layer ,cuboidal polyhedra in contact with the basal lamina and a superficial layer of cylindrical cells.
        
        It is formed by a deeper ,lower layer ,a cuboidal polyhedron in contact with the basal lamina and a superficial layer of cylindrical cells.
        
        The epithelium is only found in a few places in the body ,especially in the ocular conjunctiva ,some large excretory conductors ,and in regions of the male urethra.
        
        Simple squamous
        
        It´s tissues formed from one layer of squamous cells that line surfaces. Squamous cells are large, thin, and flat and contain a rounded nucleus
        
        These epithelia are common where absorption or transport of materials is important. They also play a role in diffusion, osmosis and filtration, selective transmembrane transport
        
        It´s found starting from capillaries to the alveoli of lungs, and nephrons of kidneys. The mesoderm line several body cavities including the pleural cavity that houses the lungs, peritoneum and the mediastinum
        
        Simple cuboidal
        
        Simple cuboidal epithelium consists of a monolayer of epithelial cells that appear to be square-shaped in cross section. With large, rounded, centrally located nuclei, all the cells of this epithelium are directly attached to the basement membrane.
        
        It´s found in the tubuli recti, rete testis and the ovary, the follicular cells of the thyroid, a nephron
        
        It´s functions are lining the ventricles of the brain and the central canal of the spinal cord, this tissue actively takes up iodine and creates thyroid hormone precursors, which are then processed and secreted into the blood. It plays a role in repairing the damage caused during every ovulation event and may also support the formation of an ovum
        
        Simple columnar
        
        Location:bronchi,uterine tubes,uterus -cillary columnar,digestive tract ,bladder-nociliated columnar epithelium
        function :allows absoption ,secretes mucous and enzymes
        
        Ciliated cells of these epithelia are found in the fallopian tubes and endometrium and are involved in the movement of the ovum. Non-ciliated cells are seen in the stomach, small intestine, large intestine and rectum.
        
        It´s functions are specially adapted for secretion and absorption. This epithelium is also structured to provide a barrier against non-specific movement of lumenal substances