Monday, October 4, 2010

Epithelial Tissue

There are 8 different types of epithelial tissue.  The first is simple squamous epithelial.

   
Characteristics: single layer of flattened cells with disc-shaped nuclei and sparse cytoplasm

Functions: diffusion and filtration and provide a slick, friction-reducing lining in lymphatic and cardiovascular systems

Examples:present in the kidney glomeruli, lining of heart, blood vessels, lymphatic vessels, and serosae

Simple Cuboidal Epithelium







Charcteristics: single layer of cubelike cells with large, spherical central nuclei

Examples:present in kidney tubules, ducts and secretory portions of small glands, and ovary surface

Function:Secretion and absorbtion

Simple Columnar Epithelium

Characteristics:single layer of tall cells with oval nuclei: many contain cilia
Goblet cells are often found in this area

Examples: ciliated type line small bronchi, uterine tubes, and some regions of the uterus


Psuedostratified Columnar



Characteristics: single layer of cells with different heights; some do not reach the free suface and nuclei are seen at different layers

Examples: present in the male sperm-carrying ducts (nonciliated) and trachea (ciliated)

Stratified Squamous 


Characteristics: thick membrande composed of several layers of cells
Examples:-forms the external part of the skin's epidermis (kertinized cells) and linings of the esophagus, mouth, and vagina (nonkeratinized cells)

Stratified Cuboidal Epithelium



Characteristics: Very rarely found, two layers thick

Examples: found in sweat and mammary glands

Stratified Columnar Epithelium


Characteristics: limited distribution in the body
Examples:-found in the pharynx, male urethra, and lining some glandular ducts
     -also occurs at transition areas between two other types of epithelia


Transitional Epithelium

Characteristics: several cell layers, basal cells are cuboidal, surface cells are dome shaped

Examples: lines the urinary bladder, ureters, and part of the urethra

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