Module 2 ECM Flashcards
What are the two main types of extracellular matrix and where are they typically found?
✅ Answer:
Basement membrane: Found under epithelial and endothelial layers; separates cell layers from connective tissue.
Interstitial matrix: Found in the spaces between cells within connective tissues.
Q2: Compare the roles of collagen type I, III, and IV in the cardiovascular system.
✅ Answer:
Type I: Found in bone, skin, tendons, and vessels; provides tensile strength.
Type III: Found in blood vessels and heart; more flexible and elastic.
Type IV: Found in basement membranes; forms network structures for support and filtration.
Explain three key functional roles of the ECM.
✅ Answer:
Structural: Provides physical support and organizes tissue architecture.
Biomechanical: Transmits mechanical forces; influences cell shape and migration
it transmits, senses, and responds to physical forces, shaping how cells behave. (regulate gene expression, cell migration [gradients and tracks], how cells stretch and shape).
Biochemical: Reservoir for growth factors, co-receptors, or source of matrikines (bioactive fragments).
What are the major structural components of ECM and their functions?
✅ Answer:
Collagen: Provides tensile strength.
Elastin: Allows tissues to stretch and recoil.
Laminin: Supports basement membrane structure and cell adhesion
What are proteoglycans and name two examples relevant to the vasculature?
✅ Answer: Proteoglycans are proteins with attached glycosaminoglycans (GAGs).
Perlecan: Found in basement membranes; contains heparan sulfate.
Decorin: Found in interstitial matrix; binds collagen and regulates fibril formation.
What is a matrikine and give an example?
✅ Answer: A matrikine is a bioactive fragment released from ECM degradation that can signal biological processes.
Example: Endorepellin, released from perlecan, promotes angiogenesis.
What enzymes regulate ECM degradation and how are they controlled?
✅ Answer:
Matrix metalloproteinases (MMPs) degrade ECM.
They are inhibited by:
TIMPs (Tissue Inhibitors of Metalloproteinases)
ADAMs/ADAMTSs (a disintegrin and metalloproteinase family)
Why does wound healing and skin regeneration decline with age?
✅ Answer: Proteins like elastin have extremely long half-lives (~70 years) and are not replaced efficiently after degradation. ECM regeneration quality declines, reducing structural integrity and healing capacity.
Describe how integrins mediate communication between ECM and cells.
✅ Answer: Integrins are transmembrane receptors that:
Bind ECM components (e.g., collagen, fibronectin).
Link to intracellular cytoskeleton via focal adhesions.
Transmit outside-in and inside-out signals to regulate gene expression, migration, and cytoskeletal changes.
List and describe three types of cell-cell junctions and their functions.
✅ Answer:
Gap junctions: Allow small molecules and ions to pass between cells.
Adherens junctions: Connect actin cytoskeletons of adjacent cells for mechanical stability.
Tight junctions: Create impermeable barriers between cells, especially in endothelial/epithelial layers.
A patient has a mutation in lysyl oxidase. Predict the impact on their connective tissues.
✅ Answer: Lysyl oxidase cross-links collagen and elastin. A mutation would weaken ECM strength and elasticity, potentially leading to fragile skin, vessel rupture, or connective tissue disorders like Ehlers-Danlos syndrome.
How does mechanotransduction contribute to vascular function?
✅ Answer: Cells sense mechanical forces (e.g., blood flow, stiffness) via ECM and transduce signals through integrins and cytoskeleton to change gene expression, affecting processes like vasodilation, remodeling, or inflammation.
