-
Cell Junctions
Need to link cytoskeleton to adjacent cells to each otherOr, need to link cyto skeleton to the extracellular matrix.
-
Tight Junctions
- The Ziploc bags of the tissue world
- Form a tight leak proof seal between two or more cells where substances cannot be allow to percolate between cells
- Example: in the inestines where it is important to keep the outside out (in the intestinal lumaen) and keep the insides of the intestinal cells from getting stale and moldy.
-
What are the different types of Cell Juncitons?
- Tight junctions
- Adherens junctions
- Desmosomes
- Hemidesmosome
- Gap junction
-
Adherens Junctions
- These use a protein called cadherin
- These work like a belt on your pants, keeps tissues from separating as they stretch and contract
-
Desmosomes
- are used as "spot welds" to hold tissue together against mechanical disruption.
- These junctions are cadherin between the cells, with intermediate filament proteins in each cell to form a continuous, strong, structure.
-
Hemidesmosome
- Half of a desmosome
- found between a cell and its basement membrane
- On the cell side, intermediate filaments anchor the cytoskeleton to the integrins, which are in turn connected to the basement membrane.
-
Gap Junctions
- The other junctions serve as mainly mechanical links
- In contrast, the gap junction serves as an electrical and biochemical link between two cells.
- A protein, connexin, forms pore-like structures called connexons (these allow small ions to pass from cell to cell)
- Monomers and polymers can pass between cells as well.
- If a cell becomes very sick, these connexons can seal off like a ships hatch, isolating the damaged cell so that it can die alone without making others sick.
-
What are Membranes?
- Flat and flexible sheets which form a lining where parts of the body come together
- They consist of and epithelium plus underlying areolar connective tissue.
-
Epithelial Membranes= epithelium + connective tissue
- -Mucous membranes
- -Serous membranes
- -Cutaneous membranes
-
Module 7
Graphic objective 21. Describe the five main types of junctions between cells. Name the most common locations or tissue types where each type of junction is found.
-
Module 7
Graphic objective 22. Define, and name key features of, the different types of epithelial membrane: mucous, serous, and cutaneous
|
|
