Ch 5 part 1 Flashcards
(83 cards)
what is epithelium
- covers body surfaces
- lines body cavities
- constitutes glands
Epithelium covers _________, lines ___________, and constitutes ______.
- body surfaces
- body cavities
- glands
What kind of tissue is epithelium tissue?
avascular
cover exterior body surfaces
line internal closed cavities and body tubes that communicate with the exterior.
what is an exception to what the epithelium covers?
joint cavities which are lined with mesenchymally derived connective tissue cells
what does the epithelium form in regards to glands?
the secretory portion (parenchyma) of glands and their ducts
what does the epithelium form in regards to the senses?
epithelial cells form as receptors for the special senses (smell, taste, hearing, and vision)
what are the three principal characteristics of epithelial tissue?
- they are closely apposed and adhere to one another by cel-to-cell adhesion molecules (C-CAM) that form SPECIALIZED CELL JUNCTIONS)
- they exhibit functional morphologic POLARITY (apical, lateral, basal domains)
- their basal surface is attached to and underlying BASEMENT MEMBRANE
in which tissue does epithelial cells lack free surfaces?
epitheloid tissues (typically most endocrine glands).
what is traditional classification of epithelial tissue based on?
- number of cell layers
- shape of the surface cells
simple epithelium
one cell layer thick
stratified epithelium
has two or more cell layers
what are the three different individual cell shapes
- squamous - width is greater than height (flat)
- cuboidal - width, depth, and height are approx. the same
- columnar - height exceeds the width
“The cells in some exocrine glands are more or less ________, with their ______ directed toward a ________”
- pyramidal
- apices
- lumen
in which epithelium is only the shape of the surface layer cell used for classification?
stratified epithelium
what are specialized apical cell surfaces that can be added to classification?
cilia or keratinization
Pseudostratified epithelium
appears stratified but is actually simple, with all cells resting on the basement membrane.
Transitional epithelium (_________)
- urothelium
- lines the lower urinary tract and can distend (stretch).
Endothelium
lines the blood (vascular) and lymphatic vessels.
Mesothelium
lines the walls and covers the contents of closed body cavities.
“Both __________ and __________, as well as _________, are almost always ____________ epithelia.”
- endo-thelium
- endo-cardium
- meso-thelium
- simple squamous
what do endothelium and mesothelium line?
the vascular system and body cavities
What are the functions of epithelium? STARE
give examples of each
- Secretion (glands, stomach)
- Transportation (respiratory track - mucous)
- Absorption (intestine - microvilli)
- Receptor function (olfactory receptors, retina - major senses)
- mEchanical protection (epidermis - moisture……)
“____________ epithelia are compatible with a high rate of ______________.”
- Simple squamous
- transepithelial transport
“__________ of the epithelium usually correlates with ____________.”
- Stratification
- transepithelial impermeability