Epithelial Tissue Flashcards
What does the polarity of epithelium mean?
all point in the same direction side by side
What germ layer(s) is epithelium derived from:?
ALL THREE
What are the 7 types of epithelial tissue?
simple cuboidal, simple columnar, pseudostratified, stratified cuboidal, transitional, stratified squamous, stratified columnar
What are the three functions of epithelium?
covering, lining, glandular
How do we classify epithelium?
arrangement, morphology (shape), specializations
What is the basement membrane?
non-cellular, semi-permeable membrane which aids in nutrient and waste product exchange
What type of surface specialization does simple columnar usually have?
brush border (microvilli)
What are the five surface specializations?
microvilli, cilia, stereocilia, keratin, goblet cells
What type of surface specialization does pseudostratified usually have?
cilia
What are the three types of epithelial junctions?
tight junctions, adherent junctions (desmosomes), gap junctions
What are tight junctions for?
forming a continuous band to seal
What are adherent junctions for?
mechanical stability by anchoring the cytoskeleton of one cell to that of another
What are desmosomes for?
very strong cohesion, in stratified squamous for mechanical stresses
What are gap junctions for?
communicating junctions and passage for ions between cells
How do exocrine glands discharge their product?
via a duct onto an epithelial surface
How do endocrine glands secrete hormones?
DIRECTLY into bloodstream
What type of secretion is water and protein rich?
serous (enzymes)
What type of secretion is viscous and thick?
lubrication or protection
Which junction anchors the cell to the basement membrane?
hemidesmosomes
Where are hormones stored in the thyroid?
FOLLICLES
What are the functions of epithelium?
protection, absorption, secretion, and/or secretion
What are the two types of epithelial tissue?
covering and lining, glandular
What structure is basically long microvilli?
stereocilia
What is the amorphous protein that is waterproof, resists friction, and relatively impervious to microorganisms?
keratin
What’s the difference between exocrine and endocrine?
exocrine has a secretory duct, endocrine glands secrete the product directly into the blood stream
