EPITHELIAL TISSUE Flashcards
What are the four basic types of tissue?
Epithelial, connective, muscular, and nerve tissues.
This is the lining of surface or body cavities; glandular secretion.
Epithelial cells
This supports and protects the tissues/organs
Connective tissue
This serves as a strong contraction; body movements
Muscle tissue
This serves as a transmission of nerve impulses.
Nerve tissue
What are the shapes of epithelial cells?
Columnar, cuboidal, and squamous cells
This has generally elongated nuclei.
Columnar cells
This has flattened nuclei
Squamous cells
This has spherical nuclei
Cuboidal cells
What is the connective tissue that underlies the epithelia lining the organs of the digestive, respiratory, and urinary system?
Lamina propia
This is the area of contact between the two tissues that can be increased by small evagination. This is often occurs in epithelial tissues that are subject to friction (E.G TONGUE, SKIN).
Papillae
This is the region of the cell contacting the extra-cellular matrix and connective tissue.
Basal pole
This is the opposite end of basal pole, it is usually facing a space.
Apical pole
This is the basal surface of all epithelia that rests on a thin extracellular. felt-like sheet of macromolecules; this is the entire structure beneath the epithelial cells that is visible with light microscope.
Basement membrane
This is the nearest structure in the epithelial cells; it usually denotes the fine extra-cellular layer seen ultrastructurally.
Basal lamina
This seals adjacent cells to one another, controlling passage of molecules between them; separates apical and basolateral membrane domains.
Tight junction
This provides points linking the cytoskeletons of adjacent cells; strengthens and stabilizes nearby tight junctions
Adherens junction/Zonula adherens
This provides points of strong intermediate filament coupling between adjacent cells, strengthening the tissue; this junction resembles a single “spot-weld” and does not form a belt around the cell.
Desmosome/Macula adherens
This anchors cytoskeleton to the basal lamina
Hemidesmosome
This allows direct transfer of small molecules and ions from one cell to another
Gap junction/Nexus
What are the proteins of tight junction?
Claudin and Occludin
These are usually uniform in length; seen in the apical cell surfaces; found in the lining of small intestine, densely packed and visible as a brush or striated border that projects into the lumen.
Microvilli
These are best seen on the absorptive epithelial cells lining the male reproductive system; it is typically much more longer and less motile than microvilli and may show branching distally.
Stereocilia
These are long, highly motile apical structures, larger than microvilli containing internal arrays of microtubules.
Cilia
What are the 2 main groups of epithelia?
Covering (lining) epithelia and Secretory (glandular) epithelia
These are organized into one or more layers that cover the surface or line the cavities of an organ.
Covering (lining) epithelia
This is found mainly in the epidermis of skin, where it helps prevent dehydration from the tissue.
Stratified squamous keratinized epithelium
This lines moist internal cavities (mouth, esophagus, and vagina) where water loss is not a problem.
Stratified squamous non-keratinized epithelium
This occurs in the excretory ducts of salivary and sweat glands.
Stratified cuboidal epithelium
This is seen in the conjunctiva lining the eyelids, where it is both protective and mucus secreting.
Stratified columnar epithelium
This line the urinary tract, extending from the kidneys to the proximal part of the urethra, and is characterized by a superficial layer of large, dome-like cells sometimes called as umbrella cells.
Transitional epithelium or urothelium
These are tall, irregular cells that are attached to the basement membrane but their nuclei are at different levels and not all cells extend to the free surface.
Pseudostratified columnar epithelium
These are epithelial cells that function mainly to produce and secrete various macromolecules and may occur in epithelia with other major functions or comprise specialized organs.
Glands
These are the cells that may synthesize, store, and release proteins, lipids. or complexes of carbohydrates and proteins.
Secretory
This is abundant in the lining of the small intestine and respiratory tract which secretes lubricating mucus that aids the function of these organs
Goblet cell
This is abundant in the lining of the small intestine and respiratory tract which secretes lubricating mucus that aids the function of these organs
Goblet cell
This secretes substances on to an epithelial surface by way of a duct.
Exocrine glands
This secretes substances on to an epithelial surface by way of a duct.
Exocrine glands
This is duct-less glands that absorbs their secreted hormone products for transport in blood to target cells throughout the body.
Endocrine glands
This is a specific mode of secretion involving secretion of entire cytoplasmic materials with remnants of dead cells, as observed in multicellular exocrine glands of reptiles, birds, and mammals.
Holocrine secretion
This is a type of exocrine gland in which the secretory products are released without resulting any damage to the cell.
Merocrine secretion
A part of the cell is excreted out together with secretory product of the cell (partial destruction)
Apocrine secretion
