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Epithelial polarity is one example of the cell polarity that is a fundamental feature of many types of cells. Epithelial cells feature distinct 'apical', 'lateral' and 'basal' plasma membrane domains. Epithelial cells connect to one another via their lateral membranes to form epithelial sheets that line cavities and surfaces throughout the ...
Epithelial cells also exhibit planar cell polarity, in which specialized structures are orientated within the plane of the epithelial sheet. Some examples of planar cell polarity include the scales of fish being oriented in the same direction and similarly the feathers of birds, the fur of mammals, and the cuticular projections (sensory hairs ...
Epithelioid cells gather around the focus of necrosis, in direct contact with the necrotic masses, forming a kind of boundary zone.. Structurally, epithelioid cells (when examined by light microscopy after stained with hematoxylin and eosin), are elongated, with finely granular, pale eosinophilic (pink) cytoplasm, and central, ovoid nuclei (oval or elongate), which are less dense than that of ...
By layer, epithelium is classed as either simple epithelium, only one cell thick (unilayered), or stratified epithelium having two or more cells in thickness, or multi-layered – as stratified squamous epithelium, stratified cuboidal epithelium, and stratified columnar epithelium, [8]: 94, 97 and both types of layering can be made up of any of ...
These cells are generally positive for alpha smooth muscle actin (αSMA), cytokeratin 5/6 and other high molecular weight cytokeratins, p63 and caldesmon. Myoepithelial cells are stellate in shape and are also known as basket cells. They lie between the basement membrane and glandular epithelium. Each cell consists of a cell body from which 4-8 ...
Epithelial cells in the medulla and dendritic cells in the thymus express major proteins from elsewhere in the body. [13] The gene that stimulates this is AIRE. [12] [13] Thymocytes that react strongly to self antigens do not survive, and die by apoptosis. [12] [13] Some CD4 positive T cells exposed to self antigens persist as T regulatory ...
TECs originate from non-hematopoietic cells that are characterized by negative expression of CD45 and positive expression of EpCAM. Then TECs are divided into two phenotypically and functionally different groups that have distinct location, cytokeratin expression, surface markers, maturation factors, proteases and function in a T cell selection.
Major function of cTECs is to positively select those T cells that are capable to recognize and interact with MHC molecules on their surface [3]. Once T cell precursors enter the thymic cortex, they start their transformation from double negative stages (T cell without surface expression of CD4 and CD8 co-receptors) to a double positive stage (T cell with surface expression of both co ...