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Histology-Epithelial
Med’11 Histology Epithelial Tissue
Question | Answer |
---|---|
What are tissues? | Tissues are groups of cells organized to perform specific functions. |
What are the 4 types of tissues? | Epithelial tissues (Epithelium). Connective tissues. Muscular tissues. Nervous tissues. |
What are the characteristics of epithelial tissues? | *Avascular *Basement membrane *Junctions *Functionally distinct surfaces *renew and regenerate |
Where are epithelial tissues found? | Cover body surfaces, line cavities and lumen and form glands. |
What are the types of different epithelial tissues? | Surface - Glandular - Neuroepithelium |
What are the types of surface epithelium? | Simple and Stratified |
What are the types of different epithelial tissues? | Surface - Glandular - Neuroepithelium |
What are the types of surface epithelium? | Simple and Stratified |
What are the types of simple epithelium? | Squamous - Cuboidal - Columnar - Pseudostratified |
What are the types of stratified epithelium? | Surface - Glandular - Neuroepithelium |
What are the types of surface epithelium? | Simple (one layer) and Stratified (more than one layer) |
What are the types of simple epithelium? | Squamous - Cuboidal - Columnar - Pseudostratified |
What are the types of stratified epithelium? | Squamous (keratinized and non-keratinized) - Cuboidal - Columnar - Transitional |
What are the characteristics of simple squamous epithelium? Where is it found? | *flat cells with flat nuclei *Function: diffusion and transport *Location: alveoli - endothelium of lymph and blood - serous membrane (pleura, peritoneum, pericardium) - Bowman’s capsule |
What are the characteristics of simple cuboidal epithelium? Where is it found? | *Cuboidal cells, central rounded nuclei *Function: absorption and secretion *Location: kidney (convoluted tubules and small collecting ducts) - glands (lining acini and small ducts) |
What are the characteristics of simple epithelium? Where is it found? | *Columnar cells, basal oval nuclei *Function: absorption and secretion *Location: GIT (glands of stomach, intestine, and gallbladder) - female genital tract (uterus, oviduct) (ciliated) |
What are the characteristics of simple pseudostratified epithelium? Where is it found? | *All cells on basement membr, not all reach surface, nuclei appear as if 2 layers *Function: transport, secretion,&protection *Many types, e.g. pseudostratified ciliated columnar epithelial w/goblet cells *Location: male urogenital tract, upper resp tr |
What are the characteristics of stratified squamous non-keratinized epithelium? Where is it found? | *Many layers: basal cells are cuboidal on clear wavy basement membr-middle cells are polymorphous-superficial cells are nucleated squam cells *Function:protection *Location:tongue-esophagus-vagina-cornea&conjunctiva-female urethra∂ of male urethra |
What are the characteristics of stratified squamous keratinized epithelium? Where is it found? | *It is similar to non-keratinized St.Squamous Epith. The superficial cells are flattened, dead and their nuclei and cytoplasm are replaced by keratin. *Function: protection *Location: epidermis |
What are the characteristics of stratified cuboidal epithelium? Where is it found? | Formed of two layers of cuboidal cells |
What are the characteristics of stratified columnar epithelium? Where is it found? | The surface cells are columnar in shape |
What are the characteristics of stratified transitional epithelium? Where is it found? | *intermediate betw st.squam&st.columnar;distend&retract; basem.membr isn’t clear¬ wavy;basal cells cuboidal;surf cells dome-shaped *Function:can stretch during urine accum;empty bladder=4-6layers; full bladder=2-3layers *Location:urinary tract |
Glandular epithelium is derived from _____. | Surface epithelium |
The classification of the body glands according to mode of secretion is _____. | Exocrine glands:secrete products onto surface by ducts as salivary, sweat, sebaceous,& mammary glands-Endocrine glands:secrete products directly into blood as thyroid, pituitary,&adrenal glands-Mixed glands: exo-&endocrine func. as pancreas,testis,&ovary. |
Classify exocrine glands according to cell number. | Singular (e.g. goblet cells) - Multicellular |
Discuss the different classifications of exocrine glands. | No.of cells:Unicellular-Multicelluar glands; Mechanism of secretion:Merocrine(exocytosis)-Apocrine(release small portion of the apical cytoplasm)-Holocrine(whole cells); Type of secretion:Mucous-Serous-Mixed-Watery-Waxy |
Give an example for each classification. | Unicell:Goblet cells in resp&dig tracts-Multicell:salivary gl.-Merocrine:parotid &pancreas-Apocrine:mammary gl.&apocrine sweat gl.-Holocrine:sebaceous gl.-Mucous:Goblet cells-Serous:parotid&pancreas-Mixed:salivery gl.-Watery:sweat gl.-Waxy:gl.of ext.ear |
What are the characteristics of neuroepithelium? Where is it found? | *Act as sensory receptors for special stimuli. Neuroepithelial cells are provided w/small hairs (hairlets) on free ends; bases are surrounded w/sensory nerves. *Function: Act as sensory receptors. *Location:taste buds in tongue-organ of Corti in int. ea |
What are the types of junctions? | Tight junctions (zonula occludens) Adhering junctions (zonula adherens) Desmosomes & Hemidesmosomes (Macula adherens) Communicating junctions (Gap junctions) |