Tissue (Extracellular Matrix) Flashcards
What is extracellular matrix (ECM)
-It has substances that surround cells in tissue
-it is made by cell of the tissue and performs functions
-it can be fluid, thick gel, or solid
What are the functions of the extracellular matrix (ECM)
-provides tissue strength to resist tensile (stretching) and compressive forces
-holds cells in their positions
-directs cells to their places
-regulates mitotic activity, and survival of cells
What are the components of the ECM
ground substance and proteins fibers
What does ground substance do
-It makes up most of the ECM
-Has extracellular fluid with water, ions, nutrients, solutes, and the macromolecule families (glycosaminoglycans, proteoglycans, and glycoproteins).
-has negative charge of sugars in GaG and attracts positive charged ion in ECF
-ions create concentration gradient in ECF
-Traps water in ECM
-helps ECM resist compression
What are glycosaminoglycans
Long polysaccharide chains (e.g., chondroitin sulfate and hyaluronic acid)
What are proteoglycans
-looks like a bottle brush
-binds to hyaluronic acid
-forms huge proteoglycan aggregates
What do proteoglycan aggregates do
-makes ECM firmer
-acts as a barrier to diffusion of substances through ECM
What are glycoproteins
-cell-adhesion molecules (CAMs)
-adheres cells to each other in the ECM
-CAMs binds to surface proteins, protein fibers, and proteoglycan
-maintains normal architecture of tissue
What are protein fibers
-has multiple fibrous protein subunits, and looks rope-like and has tensile strength
-collagen, elastic, and reticular are the main types of protein fibers in the ECM
What do collagen fibers do
-Makes up 20-25% of protein in the body
-has fibrous protein
-is resistant to tension and pressure
-is in the tendons
What do elastic fibers do
-resists tensile (stretching)
-has distensibility
-can stretch 1/2 times its resting length without breaking
-returns to original strength while stretching
-has protein called “elastin” that stretches fibers and is around glycoprotein. it is supported and organized by glycoprotein.
What are reticular fibers
-it is a collagen fiber that is thinner and shorter
-it forms meshwork or scaffold to support cells and substance of tissues
-forms webs in certain organs (spleen) to trap foreign cells
