Epithelial Tissues Flashcards
Epithelial Tissue Characteristics
Cellularity polarity attachment Avascular innervation and regeneration
sheets sit on a basement membrane
-semipermeable filter allows passage of nutrients and substances from the vasculature
Epithelium involved in secretion means they are glands
Epithelial Polarity
Apical surface: faces lumen of an enclosed tube or cavity
Basal: rests on basement membrane, anchors cell to underlying Connective tissue
Lateral surfaces:
communicates to adjacent cells
Tight/occluding junction
impermeable and allows cells to function as a barrier
encircle cells near their most apical surface
more of these mean decrease permeabillity
Proteins: Occuludins, and claudins
Gap/communicating junction:
Fluid filled channels that connect apposed cells
mediate communication
connexin aggregates
Anchoring junction
adhere something to the cell or cells together
Adherens
Desmosome
hemidesmosomes
Adherens
lateral adhesions involving cadherins that interact with the actin filament
trash bag
Desmosome
lateral adhesions involving cadherins that interact with the intermediate filaments
jeans pockets
Hemidesmosomes
basal adhesions involving integrins that lock intermediate filaments that anchor basal lamina
one rivet on basal surface
Food poisoning
bacteria target tight junctions in intestine impairing them which causes loss of tissue fluid leading to diahrrea
Gastric Ulcers via Helicobacter pylori
bacteria binds the Tight junctions in the stomach and increases permeability creating gastric ulcers
Pemphigus Vulgaris
autoimmune disease causing abnormal desmosome function which reduces the cell to cell adhesion and leads to blisters of oral mucosa
Basement membrane
specialized sheet of extracellular material
located adjacent to basal domain
selective barrier between tissues permits diffusion of nutrients
H and E stain
Apical Specialization: Microvilli
cytoplasmic process containing an actin core
used for absorption
increases surface area 20-30x
the shape and number correlate to the cells absorptive capacity
1mm long with up to 100k present on a single cell
Apical Specializations- Stereocilia
microvili of unusual length and lack of mobility
microtubule structure with actin core
increased surface area for absorption/ secretion
found in Epididymis
and hair cells of inner ear
Apical Specializations - Ciia
Long highly motile structures containing arrays of microtubules
Motile: beat in a wave like fashion to propel substances across the tissue
get rid of junk in lungs
Primary: immotile, function as chemosensors, osmosensors, mechanosensors
Nodal: Embyronic, have role in L/R axis
layer indication
name base on shape of apical level
one cell layer: simple
multiple cell layer: Stratified
Shape of the cell
name base on shape of apical level
squamous cell looks like egg
cuboidal: looks like cube
Columnar: looks like column
Simple squamous
lining of blood and lymphatic vessels
endothelium: lining of serious membranes
Mesothelium: lining of lungs, loop of henle in kidney, and various ducts
function: exchange, barrier and lubrication
Simple Cuboidal
found in kidney tubules, glands and associated ducts, terminal bronchioles, covering of the ovary
function: Absorption, barrier, secretion
Simple Columnar
found in auditory tubes, uterus, oviducts, stomach, SI/LI, gallbladder
function: secretion and absorption
Nonkeratinized Stratified squamous
LOcation is in the oral cavity, portions of the pharynx, esophogus, anus, vagina, urethra, cornea
Function: barrier and protection
lacks keratin on the surface
Keratinized Stratified Squamous
Location: epidermis of the skin
function: barrier and protection
contains keratin on the apical surface
keratin works as a waterproof barrier
stratifiied Cuboidal
location is in the sweat glands and ducts, ovarian follicles, salivary gland ducts
function: barrier and passageway
Pseudostratified Columnar Ciliated
location: lining of nasal, cavity, pharynx, trachea and bronchi
function: absorption and secretion, debris and particulate movement
contains cillia but is one layer
