Term
| What are the five classes of tissue? |
|
Definition
1. epithelial 2. connective 3. muscular 4. nervous 5. blood |
|
|
Term
| Describe the ECM (Extracellular Matrix) |
|
Definition
| It's a complex network of secreted proteins and carbohydrates that fill the spaces between cells |
|
|
Term
| Name the 3 major components of ECM |
|
Definition
1. Collagens 2. Proteoglycans 3. Multiadhesive Proteins |
|
|
Term
| Name the four principal classes of cell adhesion molecules (CAMs) |
|
Definition
1. cadherins (Ca2+ dependent) 2. lg superfamily (Ca2+ independent) 3. selectins (Ca2+ dependent) 4. integrins (Ca2+ independent) |
|
|
Term
| Which CAM mediates cell-matrix interaction? |
|
Definition
|
|
Term
| Which CAMs are Ca2+ dependent? |
|
Definition
|
|
Term
| Which CAMs are Ca2+ independent? |
|
Definition
|
|
Term
| Where are cadherins primarily found? |
|
Definition
adherens junctions and desmosomes Cadherins are so dependent on Ca that in its absence they degrade |
|
|
Term
| What is E-cadherin a key protein in? |
|
Definition
Adhesion of epithelial cells E-cadherin antibodies or removal of calcium causes cells to dissociate |
|
|
Term
| What are two subtypes of lgCAMs |
|
Definition
1. N-CAMs (adhesion of nerve cells) 2. ICAMs (Intracellular CAMs used on leukocytes) |
|
|
Term
| Based on the suffix, what do Selectins bind? |
|
Definition
| Sugars! Anything with -ectin binds sugar |
|
|
Term
| What is the primary function of selectin? |
|
Definition
Recognize oligosaccharides and mediate leukocyte-vascular cell interactions. |
|
|
Term
| What is the key selectin player and what does it do? |
|
Definition
P-selectin found on blood surface of vessels, it is Ca dependent and binds to carbohydrates. Key protein in leukocyte extravasation-the movement of leukocytes into tissue. |
|
|
Term
| What is the main function of integrins? |
|
Definition
Cell surface receptors that mediate adhesion to ECM. INTEGRATION BTWN CELL AND ECM! |
|
|
Term
| What is the function of alpha llb beta 3 integrin? |
|
Definition
Once activated it binds with collagen or thrombin which then binds with fibrinogen to form clots. Defects=no clot formation |
|
|
Term
| Integrins have a weak dissociation constant, how can they have a strong overall interaction? |
|
Definition
| the VELCRO principle- multiple weak interactions equal a strong interaction. |
|
|
Term
| Name two integrin-dependent ways cells attach to the ECM |
|
Definition
focal adhesions (actin cytoskeleton to fibronectin) hemidesmosomes (intermediate filaments to basement membrane) |
|
|
Term
| Name 3 types of cell junctions |
|
Definition
1. Tight junctions 2. anchoring junctions 3. Gap junctions |
|
|
Term
| Name three types of anchoring junctions. |
|
Definition
1. adherens junction 2. spot desmosomes (spot welds) 3. hemidesmosomes |
|
|
Term
| How do Desmosomes link together cells? |
|
Definition
| Intermediate Fibers (IFs) interconnect all of the spot desmosomes. This forms a continuous network throughout tissue---distributes force! |
|
|
Term
| What specialized cadherins are present at desmosome connections? |
|
Definition
The desmoglein and desmocolin are the cadherins that attach in the intercellular space Alright...so the IFs attach to the cytoplasmic plaque (plakoglobin and plakophilin) which is on the inside of the cell membrane. Then the desmoglein and desmocolin attach through the intercellular space. |
|
|
Term
| How are hemidesmosomes related to integrins? |
|
Definition
| Hemidesmosomes attach epithelial cells to the basement membrane...the linker proteins belong to the integrin family of extracellular matrix receptors. |
|
|
Term
| What is the purpose of Gap Junctions? |
|
Definition
Gap junctions allow the passage of small molecules such as Ca2+ between adjacent cells. |
|
|
Term
| What makes up gap junctions? |
|
Definition
connexins Two connexins form a continuous channel btwn cells Close when sense high concentration of calcium-prevent cascading cell death |
|
|
