Cell Interactions 1: The ECM Flashcards
what do multicell organisms make contact with? (2)
other cells or ECM
basal lamina
fibroblast & epithelial cells together make the basal lamina or basement membrane
compressed ECM, resilient to epithelial cells
what tissue is almost entirely composed fo ECM material?
connective tissue
what function does the ECM serve when it is a thin layer?
holds cells close together
what function does the ECM serve when it is a thick layer?
cushions or protects
how many specialized cell types do vertebrates have?
100+
what type of ECM do plants, fungi & bacteria have?
a tough ECM, called ‘walls’
what is the role of the ECM in anthropods? & what is the main component?
chitin is the main component
forms exoskeleton
what are the most abundant polymers on earth?
chitin
cellulose
what is the ECM composed of ?
primarily water
PROs
carbs
what are the main macromolecules in the ECMs of animals?
Glycosaminoglycan (GAGs): polysaccharide with an amino grp
PROs –> collagen, elastin, fibronectin & laminin
Proteoglycans: PROs with GAGs covalently bonded
where does the ECM come from?
cells secrete it & secrete surplus for other cells
what type of ECM do fibroblasts have?
connective tissue ECM
what type of ECM do osteoblast cells have?
bone-forming ECM (calcified ECM)
what type of ECM do chondroblast cells have?
cartilage forming ECM
when is the ECM calcified?
bones & teeth
cell wall of bacteria
shells of molluscs
ECM function
Mechanical support
Biochemical barrier
Water soluble materials pass, lipid soluble materials cannot pass & macromolecules move slowly
A medium for:
Extracellular communication with CAMs
Positioning of cells in tissues through adhesions
Repositioning of cells in migration during cell development or wound repair (cells push along ECM)
Tensile strength for tendons
Compressive strength for cartilage
Hydraulic protection
Elasticity in the walls of blood vessels
Calcified for: bones/teeth, cell wall of bacteria & shells of molluscs
Chitinized to form the exoskeleton
why are glycocalyx interactions not considered glycoPROs?
not covalently linked
glycocalyx
carbs attached to the PM PROs & lipids
what is the function of the glycocalyx?
Cell-cell interactions (carbs)
Cell substrate interactions (receptors) Mechanical protection Binding regulatory factors
where is the basal lamina found?
epithelial layers & connective tissues
around muscle & fat cells
under epithelial tissues
Under endothelial lining of blood vessels