ANAT241 Lecture 8 - Epithelial Tissue and Cell Membrane Specialisations Flashcards
what are tissues?
tissues are specialised, similar cells embedded in an extracellular matrix (ECM)
what are the 4 tissue types?
epithelial tissue
connective (support) tissue
muscle tissue
nervous tissue
what are cells composed of?
an internal cytoskeleton network
what is the function of the internal cytoskeleton network?
for shape, support and movement
what do cells secrete?
extracellular matrix (ECM)
why do cells secrete extracellular matrix?
for support, structure, regulation of cell communication and behaviour
where does epithelial tissue line?
lines organs and cavities within the body and covers the external body as the epidermis
what is epithelial tissue?
a protective barrier with absorptive and secretory adaptations that has polarity with an apical and basal surface and a basement membrane that acts as a scaffold to underlying connective (support) tissue
how does epithelial tissue acquire nutrients?
epithelial tissue is avascular and therefore acquires nutrients via diffusion
what allows the regeneration of epithelial tissue layers?
stem cells
what 3 criteria is epithelia classified based on?
classified based on cell shape
the number of cell layers
cell surface specialisations
what are the 3 types of epithelial cell shape?
squamous
cuboidal
columnar
what are the 4 types of epithelial cell layers?
simple
stratified
pseudo-stratified
transitional
what are the 2 epithelial cell surface specialisations?
microvilli and cilia
what are microvilli?
finger-like projections of the plasma membrane
what is the size of microvilli?
they are short between 0.5um and 1um
what is the function of microvilli?
increase the surface area for absorption in the intestine and kidney
what are microvilli composed of?
composed of a core of parallel actin bundles
what do microvilli appear as under light microscopy?
appear as a brush border
what do microvilli appear as electron microscopy?
appear as individual microvilli
what is the shape of microvilli maintained by?
maintained by actin filaments
what are cilia composed of?
a cytoskeleton with a core of microtubules
what is the size of cilia?
they are half of the cell length as they are upto 10um long
what is the function of non-motile cilia?
to provide sensory information