| Front |
Back |
| What are the diff. types of Cell Junctions? |
Specialized attachments b/w adjacent cells; Tight Junctions (zona occludens); Adhesive Junctions; Gap Junctions |
| Specialized attachments b/w adj. cells |
Provides anchoring of adj. cells to one another and provides cytoplasmic continuity b/w cells |
| Tight Junctions (Zona Occludens) |
Seal cell-lined compartments; Prevent water soluble molecule from passing through b/w cells; fuse adj. plasma membranes; Maintains polarity of cell; Disrupted by reduction of calcium concentration |
| What are the two types of Adhesive junctions? |
Zonula Adherens & Desmosomes. Hemidesmosomes not in terminal bar |
| Zonula Adherens |
Membrane proteins CADHERIN of adj cells bind to adhere cell to each other and the actin microfilaments in cell cortex anchor adherin proteins |
| Desmosomes |
Are disc shaped and Cytoplasmic Intermediate Filaments anchor the adherin family membrane proteins that bind the cell |
| Hemidesmosomes |
Found in basal layer of cells. Use INTEGRIN proteins to attach cell to extracellular matrix |
| Gap Junctions |
Not found in terminal bar. Does not hold cells together. Allows for passage of ions & small molecules b/w adj. cells. Cells connected by connexons made of protein Connexin. Imp. in cardiac & smooth muscle=mult. cells act as one |
| What are the 3 types of junctions found in the terminal bar? |
Tight Junctions (zona occludens), Zonula adherens, desmosomes |
| What are the 3 types of surface specializations? |
Microvilli, Stereocillia, and Cilia |
| What is the purpose of a surface specialization? |
To incr. surface area and to move substances across cell surface |
| Microvilli |
Covered w/ glycocalyx; Forms striated border; Found on apical surface of absorptive cells; Core of ACTIN filament helps maintain cell shape; NOT Motile only incr. surface area |
| Stereocilia |
Long branched microvilli; Incr. surface area for TRANSPORT across membrane |
| Cilia |
Motile; aka Axoneme (gen. term for cilia and flagella) Move material through the surface of cell & move cell through its environ. Composed of tubulin; requires ATP energy; motor protein is axonemal dynein |
| What is the structural composition of cilia & Microvilli? |
Cilia-Tubulin protein; Microvilli-Actin protein |
mr. charles11
