Term
| What three morphological characteristics are epithelia classified by |
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Definition
1. Number of cell layers
2. Shape
3. presence of surface specializations |
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Term
| What are the 3 functions of simple epithelia |
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Definition
1. Selective diffusion
2. absorption
3. secretion |
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Term
| What are the two types of epithelia based on number of cell layers present |
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Definition
1. Simple - 1 cell layer
2. Stratified - 2+ cell layers |
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Term
| What are the 3 types of epithelia based on shape and their characteristics |
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Definition
1. Squamous - flattened, irregular shape, form continuous lining, selective diffusion
2. Cuboidal - square, usually secrete or absorb
3. Columnar - taller then they are wide, usually absorb |
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Term
| What are the 4 types of stratified epithelia |
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Definition
1. stratified squamous - line most tissues subjected to abrasion
2. stratified squamous keratinized - resist abrasion and desiccation, dead outer layer of cells (anucleated)
3. Stratified cuboidal - provide robust lining
4. Transitional - withstand stretch and toxicity of urine |
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Term
| What do cilia do and how do they work |
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Definition
| They propel fluid, have microtubules inside that use proteins (dynein) to make them move. |
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Term
| What do microvilli do and how do they work |
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Definition
| They are membrane projections that increase surface area for pumps or other transporters and allow additional absorption and secretion |
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Term
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Definition
| Non motile structures in the epididymis that facilitate absorption. |
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Term
| What are the two major roles of tight junctions |
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Definition
1. Fence - separate the proteins on the basolateral side from those on the apical side
2. Regulate the movement of solutes between cells |
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Term
| What molecules form gap junctions and what purpose do they serve |
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Definition
| Proteins called connexins combine for form connexons which allow cell-cell communication |
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Term
| What molecules form the connections in adherens junctions |
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Definition
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Term
| What 2 major benefits do desmosomes and hemidesmosomes provide to cells |
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Definition
1. Dispersion of force - increases cell strength and integrity
2. Mechanochemical signaling - Allows cells to sense and react to mechanical stress |
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