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23 Cards in this Set
- Front
- Back
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Simple Squamous
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-nucleus protrudes into lumen
-flattened cells adjacent to each other Examples: -Lining of vessels (endothelium) -serous lining of cavities -pericardium -pleura -peritoneum (mesothelium) -alveoli -loop of henle and parietal layer of bowman's capsule Function: -facilitates movement of viscera (mesothelium) -active transport by pinocytosis (mesothelium and endothelium) -secretion of biologically active molecules (mesothelium) -diffusion across tissue, in and out of lumen |
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Simple Cuboidal
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-centrally located nucleus
Examples: -covering the ovary -thyroid -interior surface of tympanic membrane -ducts of many glands -tubules of kidney Function: -covering -secretion -conduction involving various metabolic processes |
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Simple Columnar
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-height greater than width
-nuclei near basement membrane Examples: -lining of intestine and stomach -galbladder -inner ear -larger glands and ducts Function: -protection -lubrication -absorption -secretion -conduction involving complex metabolic processes |
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Pseudostratified
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-all rest in basal lamina but not all reach lumen
-usually ciliated and combined with goblet cells Examples: -lining of trachea -male urethra -middle ear Function: -protection, secretion -cilia mediated transport of particles trapped in mucus out of the air passages |
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Stratified Squamous Keratinized (dry)
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-highly resistant to irritation
Example: -Epidermis Function: -protection against dry environments -prevents water loss -lines dry surfaces exposed to continuous trauma |
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Stratified Squamous nonkeratinized (moist)
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-highly resistant to irritation
Examples: -mouth -esophagus -vagina -anal canal Function: -protection, secretion -prevent water loss -lines wet surfaces exposed to trauma |
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Stratified Cuboidal
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-most prominent in large ducts of glands
-single, large duct Examples: -sweat glands -developing ovary follicles Function: -protection -secretion |
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Stratified Transitional
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-apical cells bulge slightly into lumen
-some cells bi-nucleated -apical cell surface stains slightly more deep pink (actin filaments) exists in 2 states: Extended - flattened, few layers, more surface area, full bladder contracted - taller, more layers, less SA; membranes stored within cytoplasm as vesicles Examples: -bladder -ureters -renal calyces Function: -protection -distensibility |
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Stratified columnar
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-two layers = basal cuboidal, superficial columnar
Examples: -conjunctiva -male urethra -larger ducts (ex. submandibular salivary glands) Function: -protection |
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What are characteristics of the Basal laminae?
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PAS positive because of glycogen
Lamina lucida (less dense) - beneath epithelium lamina densa (more dense) - basal lamina + reticular lamina composition: Collagen Type 4,7: -7 is PAS positive due to richness of carbs -4 is for structural stability, uses Laminin as bridge Entactin (adhesive glycoproteins) - bridge between laminin and type 4 collagen Fibronectin (secreted by fibroblasts) - same as entactin Laminin (adhesive glycoproteins) - bridge between cells and type 4 collagen |
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What are characteristics of Microvilli?
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increase surface area; interaction of actin and myosin aids in absorptive process
apical surface (striated border) glycocalyx aids in absorption has brush border enzymes like lactase and alkaline phosphatase found w/ cuboidal in proximal tubule of kidney and columnar in intestine |
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What are characteristics of sterocilia?
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modified microvilli (pseudostratified)
only found in inner ear and epididymis in epididymis they have absorptive functions and long and branching, in inner ear they have receptor functions and regular arrangment |
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What are characteristics of Cilia?
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numerous in respiratory tract where they sweep out mucus
also found in maculae and cristae of ear and rod of retina and serve as receptors |
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What are characteristics of Basal infoldings?
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Basal side of cell
Mitochondria and ATPase (inhibited by Ouabain) Increase SA Striated Duct Mitochondria are between the infoldings Found in proximal tubule and salivary glands |
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What are characteristics of Transitions of Epithelia?
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Areas where one epithelium ends and other begins
Vulnerable to neoplasms and infections Found in cervix of uterus, gastroesophageal junction, and ano-rectal junction |
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What are characteristics of Zonula Occludens?
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surround entire apical perimeter of adjacent cells
transmembrane proteins attached directy lo each other: -occludins, claudins -JAM (junctinoal adhesion molecule) EG. Brain, GIT, Lungs, Testis, Retina |
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What are characteristics of Zonula Adherens and what are Focal adhesions?
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surround entire perimeter of epithelial cells
interact with actin, comprises terminal web Protein: E-cadherin which depends on Ca++ found in neural tube defects focal adhesions - zonula adherens in non-epithelial cells |
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What are characteristics of Macula adherens?
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known as Desmosomes
weld or rivet between adjacent cells cell to cell adhesion found where there is stress (skin) proteins: keratin, dosmogleins, desmoplakin, desmocollins, Ca++, polygonal cells have most desmosomes pathologies involved: -blistering disease -pemphigus vulgaris or foliaceus |
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What are characteristics of gap junctions?
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found in CNS, cardiac and smooth muscle
plaque-like with connexons permits passage of ions and small molecules (glucose) bypasses plasma membrane and connects directly to cytoplasm good example is an electrical synapse between neurons |
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What are characteristics of hemidesmosomes?
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mediate adhesion of epithelial cells to underlying matrix
adhere cells to basement membrane on basal surface of basal cells --> tracheal epithelium, stratified squamous epithelium, myoepithelial cells keratin fibers terminate in hemidesmosome plaque linked via integrins to laminins in basal lamina |
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What are the 3 different types of cells?
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Labile:
-continually divide -stem cells are common example -due to high mitotic rate are vulnerable to mutation and malignancies ex. surface epithelial cells, hematopoietic cells, and lymphoid cells stable cells: -known as quiescent cells -low level of replication -susceptible to mutation during high mitotic rates because can rapidly divide with certain stimuli ex. glandular organs permanent cells: -unable to divide -can increase in size ex. brain, renal corpuscles, and cardiac muscle |
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What are examples of metaplasia?
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Chronic cigarette smokers:
-pseudostratified ciliated epithelium transformed to stratified squamous epithelium in bronchi chronic vit A deficiency: -transitional epithelium of urinary bladder and bronchi replaced by stratified squamous chronic acid exposure or reflux esophagitis: -epithelium of esophagus replaced by simple columnar with mucin secreting cells |
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What are anaplasia and dysplasia?
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anaplasia:
-in malignant tumor cells -loss of differentiation -cells revert back to embryonic appearance dysplasia: -increase of immature and decrease of mature cells -indicative of early neoplastic process |
