Epithelial tissues
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Epithelial tissues: are tissues covered surfaces of the body and internal organs, line
cavities, and form glands.
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Function: may be protective, absorptive, secretory, or excretory.
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characterized by:
1. Closely packed cells without intercellular substances or blood vessels
2. Presence of a noncellular basement membrane that attaches the tissue to
underlying connective tissue.
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Categorized on the basis of :
1. Single or multiple cell layers
2. Cell shape
3. Presence or absence of cilia
Type of
epithelium
Subclassification 1
simple
Squamous
Lining blood vessels (endothelium), lining body
cavities(mesothelium), alveoli of lungs, and loop of
Henle of kidney
Cuboidal
Collecting tubules of kidney, small ducts of exocrine
glands, thyroid gland, pancreas, sweet glands,
salivary glands, surface of ovary, retetestis
Columner
Pseudostratified
Stratified
Squamous
Subclassification 2
Site
Ciliated
Fallopian tubes and small bronchi of lungs
Non-ciliated
Gall baldder, Collecting ducts of kidney, endocervix,
digestive tract from stomach to anus
Ciliated
Respiratory tract including nose and sinuses
Non- ciliated
Parts of male urethra and in large ducts of parotid
salivary gland
NonKeratinizing
Lining oral cavity, epiglottis, oesophagus, anus,
cervix, vagina, cornea
Keratinizing
Skin (Epidermis)
Cuboidal
Large ducts of exocrine glands, ducts of sweet
glands, in sperm-forming tubules of testis
Columner
Conjunctiva, parts of pharynx and eplglottis, and
anal canal
Transitional
Lower urinary tract (renal pelvis, ureters, bladder
and urethra)