CH.5 EPITHELIAL TISSUE ORGANIZATION Flashcards
What is Epithelial Tissue?, Does it have extracellular matrix, and what is the composition?
-Covers the body surfaces, lines body & organ cavities, & forms organs.
-Contains little to none Extracellular matrix
Composed of one ore more layers of closely packed cells.
What are the 6 Characteristics Of Epithelial Tissue?
a) Cellularity: Composed of tightly packed cells.
b) Polarity: Apical & Basal Surface
c) Attachment of a Basement membrane: Acts as glue to strengthen attachment & barrier
d) Avascularity
e) Extensive Innervation
f) High Regneration Capacity: Cells undergo cell division freq at deepest Epi cells.
What is Basal Surface?
Deep/fixed Surface region of E.T.
-This constantly regenerates as cells in the Apical Layer are lost because of Abrasion or stress.
What is Apical Surface?
Exposed area either external environment or internal body space.
What is Microvilli?
-Small membranous projections on Apical Surface of Cell.
- It increases for secretion and absorption
What is Cilia?
Moves mucus past surface of celll.
What are the four functions of Epithelial Tissue?
1) Physical Protection: Both external & internal surfaces from dehydration, Abrasion, & destruction by Physical, Chemical or Biological Agents.
2) Selective Permeability
3) Secretion: Glands
4) Sensations: Innervated
What are the three Epithelial Cell Layers?
-Simple
-Stratified
-Pseudostratified
What are Simple Epithelium Cells and where are they found?
-One layer that is in direct contact with the basement membrane.
-Found in areas where stress is minimal, filtration, absorption, or secretion.
What are Stratified Epithelium Cells, function, & where are they found?
- Two or more layers
-Only found in the deepest (Basal) layer in direct contact with Basement Membrane. - Provides structural support or better protection for underlying tissue.
What is Pseudostratified, Where can they be found, & What layer is it Classified under?
- Falsely stratified because cell’s nuclei is distributed at different levels between Apical & Basal Surface.
All cells reach Basement membrane but not ALL reach Apical Surface
-Simple Epithelium because all cells attached to Basement Membrane.
What are the Four Epithelial Cell Shapes?
-Squamous, Columnar, Cuboidal, & Transitional
How is Epithelial Cell shape determined?
- The shape of cell at Apical Surface.
What are Transitional Cells?
-Can readily change their shape from polyhedral to more flattened.
(Depends on the degree of Epithelium is stretched.
Where is Simple Squamous Epithelia found?
-Air sacs in lungs (alveoli),
-Lining of lumen of blood vessels & lymph vessels (Endothelium).
-Serous membranes of body cavities (mesothelium)
What does Endothelium mean?
Name of Simple Squamous Epithelium that lines blood vessels & lymph vessels.
What does Mesothelium mean?
Name of Simple Squamous Epithelium that forms Serous membranes of body cavities.
What is Simple Cuboidal Epithelium’s Function?
-Absorption & Secretion.
-Forms secretory tissue of most glands and small ducts.
Where is Simple Cuboidal Epithelium Found?
-Lining of Kidney Tubules, –Thyroid gland follicles,
-Surface of ovary,
-Secretory regions & ducts of most exocrine glands.
What is Nonciliated Simple Columnar Epithelium?
-Does not contain Cilia.
-Contains Microvilli & Goblet cells. -Apical Surface.
What are Goblet Cells?
They secrete mucus (happens when hydrated Glycoprotein which form mucus.
What is another name for Brush Border?
-Microvilli,
-Named this people they appear bright & fuzzy.
What is the Function of Non-Ciliated Simple Columnar Epithelium?
- Absorption & Secretion.
Where is Non-Ciliated Simple Columnar Epithelium located?
Lining of most of gastrointestinal tract (Small & Large Intestine, and the digestive tract)
