Anatomy_Concepts_Ch4 Flashcards
Epithelia functions include:
Protection of the underlying tissues<br></br>Secretion (release of molecules from cells)<br></br>Absorption (bringing small molecules into cells)<br></br>Diffusion (movement of molecules down their concentration gradient)<br></br>Filtration (passage of small molecules through a sieve-like membrane)<br></br>Sensory reception
special characteristics of epithelia
Cellularity<br></br>Specialized cell junctions<br></br>Polarity (apical surface and basal surface)<br></br>Support by connective tissue<br></br>Avascular but innervated (has nerve endings but not blood vessels)<br></br>Regeneration
classification of epithelia
number of cell layers (simple and stratified)<br></br>shape of the cells (squamous, cuboidal, columnar)
classifications of glands
endocrine or exocrine; unicellular or multicullular
classification of multicellular glands
simple glands or compound gland (unbranched or branched duct);<br></br>tubular, aveolar (or acinar), or tubuloalveolar (secretory cells form tubes, spherical sacs, or both)
classes of connective tissue
connective tissue proper (e.g. fat tissue and the fibrous tissue of ligaments); cartilage; bone tissue; blood
special characteristics of connective tissues
Relatively few cells, lots of extracellular matrix.<br></br>Extracellular matrix composed of ground substance and fibers. (3 types of fibers: collagen fibers, reticular fibers, and elastic fibers).<br></br>Embryonic origin (mesenchyme).
primary cell type
fibroblasts (connective tisssue proper); chondroblasts (cartilage); osteoblasts (bone) while secreting matrix, after done they are called fibrocytes, chondrocytes, and osteocytes
areolar connective tissue basic functions
Supporting and binding other tissues<br></br>Holding body fluids<br></br>Defending the body against infection<br></br>Storing nutrients as fat
cell junctions
Three factors act to bind epithelial cells to one another: adhesion proteins in the plasma memranes of the adjacent cells link together in the narrow extracellular space; the wavy contours of the membranes of adjacent cells join in a tongue-and-groove fasion; and there are special cell junctions (characteristic of epithelial tissue but are found in other tissue types as well).
multicellular exocrine gland examples
simple tubular: intestinal glands<br></br>simple branched tubular: stomach (gastric) glands<br></br>compound tubular: duodenal glands of small intestine<br></br>simple alveolar: no important example in humans<br></br>simple branched alveolar: subaceous (oil) glands<br></br>compound alveolar: mammary glands<br></br>compound tubuloalveolar (salivary glands)
