Transcript Tight Junctions, Gap Junctions, and Extracellular Matrix

By Rachel and Sara Lembke
Period 6
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Tight junctions are composed of branching
networks of sealing strands.
The efficiency of the junction is increased
because each strand acts independently.
Sealing strands are formed from a row of
transmembrane proteins embedded in both
plasma membranes.
The major types of junction are claudins and
occludins.
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Hold cells together.
Help maintain the polarity of cells.
Prevent the passage of molecules and ions
through the space between the cells, which
forces the materials to pass through the
tissue in order to enter the cell.
A specialized intercellular connection between a
multitude of animal cell-types.
• Composed of two connexons which connect
across the intercellular space.
• Composed of small channels that permit small
molecules to shuttle from one cell to another,
linking the interior of adjacent cells.
• Do not seal membranes together, nor do they
restrict the passage of material between
membranes.
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Directly connects the cytoplasm of two cells which
allows various molecules and ions to pass freely
between the cells.
Allows for direct electrical communication between
cells.
Allows for chemical communication between cells
through transmission of small second messengers.
Prevents large molecules such as nucleic acid and
protein from cytoplasmic transfer between cells.
Ensures that molecules and current passing through
the gap junction do not leak into intercellular space.
Notable use is the electrical synapse found in some
neurons.
Cancer cells generally demonstrate poor or absent gap
junction communication.
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Includes the intersitial matrix and basement
membrane.
A complex network of polysaccharides and
proteins secreted by cells.
Is assembled into an organized meshwork in
close association with the surface of the cell
that produced them.
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Provides support and anchorage for cells
Segregates tissues from one another
Regulates intercellular communication
Essential for processes like growth, wound
healing, and fibrosis.
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www.wikipedia.org
http://www.vivo.colostate.edu/hbooks/cmb/c
ells
http://www.csm.ornl.gov/SC98/viz/viz4.html
http://www.ncbi.nlm.nih.gov/bookshelf/br.fc
gi?bo
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