Micro - Epithelium Flashcards
Tissue Definition
Group of structurally or physiologically similar cells + intercellular substance that surrounds them
4 basic tissue types
Epithelium, CT, Muscle, Nerve
Organ definition
made from tow or more different tissue types that work together to perform specialized functions
Characteristics of epithelium
Closely apposed, sit on CT, sit on a BM membrane junctions not speciailzed for contraction polarized - apical, basal etc AVASCULAR High mitosis rate step cells
Membrane junctions hold cells together
Tight junctions, zonulae adherentes, desmosomes
Membrane junctions to communicate
gap junctions
Membrane junctions to bind to BM
hemidesmosomes, focal adhesions
Microvilli
Actin, increase surface area
sit on terminal web
Brush border/striated border - visible by LM
Terminal web
network of actin filaments + proteins anchored to zonula adherens and apical membrane
rests on a network of IF
Glycocalyx
fuzzy layer on top of cells
Carbohydrate side chains of glycoproteins
Digestive enzyme activity, hormone receptor site, cell to cell recognition
Stereocilia
Actin, terminal web
longer than microvilli
FOund only on male reproductive tract and sensory hair cells
Cilia
MTs
Cilium grows from 9 triplets basal body
Ordinary Cilia
Motile, MTs
Axoneme - 9+2 MT
Has dynein arms for motility
On only a few epithelia but numerous on those cells
Clump together
Basal bodies - show up as dark line on apical side
Primary cilia
Nonmotile Axoneme - 9+0 MT No dynein arms Only one cilium per cell Sensory structures that send signals
POlycystic kidney disease
Mutant genes that code for primary cilia
Numerous cysts that destroy the kidney cortex
Basement membrane composition
Basal lamina + lamina reticularis
Hemisdesmosomes, focal adhesions
Basal lamina structure
Lamina lucida - light color
Lamina densa - dark color
epithelial cells make the components
Reticular lamina
CT cells make the components
Fibroblasts
Basement membrane functions
Anchor epithelia to CT
semipermeable filtration barrier
Regulate growth of blood vessels
Transitional epithelium
Relaxed state - large dome shaped
Stretched state - flat and rectangular
Binucleate sometimes
Keratinized Stratified squamous epithelium
Minimally - surface cells alive - visible nuclei
found on moist body surfaces
Maximally - surface cells are dead - no nuclei
Found on dry body surfaces
Endothelium
Simple squamous epithelium that lines the lumen of all BV, lymphatic vessels, heart chambers
Mesothelium
Simple squamous that lines walls of body cavities, outer surfaces of organs (lungs, heart, stomach)
Simple Squamous location
Endothelium
Mesothelium
Renal corpuscles wall
