Exam II Flashcards
histology
the study of tissues
epithelial
sheet of cells covering or lining a body surface/cavity
nervous
specialized cells generate and conduct nerve impulses to control body
muscle
highly cellular and vascularized tissues responsible for most body movement
connective
the most abundant and widely distributed tissue found through out the body composed of several variations in cell composition
polarity
all epithelia exhibit apicalbassal polarity. this means that the regions of cells near the basal surface differ from apical cells in their structure and function. their locations are maintained by the cytoskeleton of epithelial cells
specialized contacts
with the exception of glandular epithelia, the epithelial cells fit together snuggly (by means of tight junctions or desmosomes) in order to form continuous sheets of tissue
connective tissue support
connective tissue supports and lies beneath all sheets of epithelial tissue. this is done by two laminae that make up the basement membrane
vascularity
the epithelium in innervated (supplied by nerve fibers), but is avascular and holds not blood vessels. they receive their nutrients by diffusing substances from blood vessels in underlying connective tissues
regeneration
exposure to friction and “wear and tear” the epithelial cells have a high regeneration capacity. they can rapidly reproduce themselves by cell division when the apical basal polarity and lateral contacts are destroyed as long as they have adequate nutrition
simple epithelia
single cell layer; simplest of all epithelium
simple squamous
- laterally flattened
- disc-shaped central nuclei
- sparse cytoplasm
simple squamous functions
- filtration
- diffusion
- secretion
simple squamous locations
- kidney’s glomeruli
- air sacs in lungs
- heart linings
- blood vessels
- lymphatic vessels
- lining of ventral body cavity
simple columnar
- tall cells
- round to oval nuclei
- some cells have goblet glands (unicellular and mucus-secreting)
simple columnar functions
- absorption
- secretion of mucus, enzymes and other substances
- ciliary action propels mucus
simple columnar locations
- most of digestive tract; stomach to anal canal (nonciliated type)
- gallbladder
- excretory ducts of some glands
- small bronchi, uterine tubes, regions of uterus (ciliated type)
simple cubodial
- tall and wide
- spherical nuclei that stain darkly
simple cubodial functions
- secretion
- absorption
simple cubodial locations
- kidney tubles
- ducts
- secretory portions of mall glands
- ovary surface