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13 Cards in this Set
- Front
- Back
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Microvilli
Stereocilia Cilia |
1. Microvilli- actin (microfilaments)
2. Stereocilia- actin (branched, long, uncommon) 3. Cilia- tubulin (microtubules) |
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Cilia Structural Modifications
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- 9 + 2 pattern
- the basal body is the anchor- has nine triplets and no central pair - nexin helps to link the doublets together - the radial spoke is important - dynein- motor proteins that "walk" along microtubules (contracts and pulls down neighboring tubule and causes cilia to bend) |
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Immotile Cilia Syndrome- a number of diseases (two examples:)
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1. Kartagener's Syndrome- lacking dynein arms, so cilia can't move (symptoms: infertility in both men and women, respiratory problems)
2. Young's Syndrome- missing the radial spoke; similar symptoms 3. Situs inversus- organs are switched in the body- flipping of organs during embryonic development (cilia is used to move organs and doesn't in this disease) |
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Chlamydomonas reinhardii
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- research on cilia and flagella is done on these
- FLA-10 gene- disrupts dynein if disturbed and causes hereditary defects in humans |
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Lateral Domain
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- communicates with adjacent cells
- characterized by special attachment areas (adhesion molecules) |
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Terminal Bars
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- dark bands along the tops of epithelium
- the junctional complex is present in terminal bars |
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Junctional Complex Components
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1. Occluding junctions- keeps things out
2. Adhering junctions- adheres things 3. Communicating junctions- communication |
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Occluding Juctions (zonula occludens)
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- found on the apical-most end of the cell
- there are strands all the way through (more strands create a more impermeable barrier; less strands create a more semipermeable barrier) |
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Occluding Junction proteins
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1. Occludins- set up the barrier
2. Claudins- most significant - occludins and claudins connect to themselves 3. JAM- junction adhesion molecule (IqSF) 4. Z01- binds to actin 5. Z02- involved in signaling 6. Z03- interacts with ZO1 and occludin - Z01, Z02, and Z03 link the cytoskeleton to adhesion molecules |
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Transport of Occluding Junctions
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- paracellular pathway (more like diffusion; goes in between the cells)
- transcellular pathway (involves active transport) - channels are created by claudins |
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Anchoring Junctions
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- found underneath occluding junctions
two types: 1. Zonula adherens 2. Macula adherens (desmosomes)- small spot-wells |
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Zonula adherens
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- made of adhesion molecules (E cadherins) and hold cells together
- below occludens - E cadherin (cell adhesion molecule that requires calcium- use cadherins instead of claudins and occludins) - Fuzzy plaque |
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Macula adherens (desmosomes)
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- Tight Junctions
- adhesion molecules linked to patch-structure on inside of cell - link to intermediate filaments |
