Module 3: Lesson 5 Flashcards
(21 cards)
What are the two building strategies that multicellular organisms use to organize and support tissue structure and function?
Cell-cell adhesions and strength of the extracellular matrix.
What are connective tissues?
Tissues in which the extracellular matrix makes up the bulk of the tissue and carries the mechanical load such as bone, tendon, and dermis of the skin.
What is the extracellular matrix?
A complex network of proteins and polysaccharide chains that the cells secrete and deposit around themselves as an insoluble material.
What are the two forms of extracellular matrices?
The basal lamina and the extracellular matrix of animal connective tissues.
What are glycoproteins?
Fibrous proteins with many short branched oligosaccharide chains, bound by conventional asparagine (N)-linked oligosaccharides.
What are proteoglycans?
A small protein part and unbranched covalently-bound polysaccharide chains.
What is the basal lamina?
A very thin, tough sheet of matrix molecules which underlies all types of epithelia and separates it from connective tissue. It also lies between two sheets of cells to act as a selective filter.
What is the role of the basal lamina?
To provide basic structural support, establish cell polarity, promote cell survival by providing scaffold for injured tissue to regenerate and refurbish the original tissue architecture, and filter to help determine what molecule will pass from blood to urine.
What is laminin?
The primary organizer of the basal lamina structure. Three chains use disulfide bonds to form a cross-like structure. There are a, b, and g subunits,
What is an essential component of the basal lamina?
Collagen IV, which has globular domains that interact with each other and with other molecules to assemble extracellularly into a flexible, felt-like network.
What are the basal lamina linkers? What is the transmembrane receptor?
Basal lamina linkers are nidogen and perlecan. Integrin is the transmembrane receptor.
What is fibronectin?
An extracellular protein that helps cell attach to the matrix via a transmembrane receptor.
What is the difference between “outside in” and “inside out” when it comes to integrin switches?
“Outside in”: the binding of an external matrix protein can drive some integrins to switch from the inactive to active state.
“Inside out”: Intracellular regulatory signals stimulate assembly of proteins to interact with the b-chain to trigger activation.
What are fibroblasts within the extracellular matrix?
The main contributors of ECM material. Chondroblasts form cartilage, and osteoblasts form bone.
What are types of glycoproteins?
Collagens, fibronectin, elastin, etc.
What are glycosaminoglycans (GAGs)?
Polysaccharide chains of proteoglycans. Example: Hyaluronan
What are the four main groups of GAGs distinguished by?
Sugars, type of linkage between sugars, and the number of location of sulfate groups.
What are the functions of GAGs?
To serve as space fillers, resist compression, and act as filters.
What are collagens within the extracellular matrix?
The main protein in the ECM that resists tensile (stretching) forces in the fibril structure.
Why is it important for a cell has the ability to cut through the ECM?
It enables cells to divide while embedded in the matrix; the cell needs to stretch in order to divide and a rigid ECM is inhibitory. It enables the cells to migrate through the ECM.
What classes of proteolytic enzymes cooperate to degrade matrix proteins?
Matrix metalloproteases and serine proteases.
