cell adhesion and connection to the ECM Flashcards
what are some important fibrous components of the ECM?
collagen, elastin, fibronectin and laminin
also proteoglycans
what fibres to fibroblasts secrete?
collagen, elastin and proteoglycans
what is an important feature of fibroblasts which can be seen in histology?
they have abundant RER which can be stained
what is pro collagen?
collagen myofibrils twisted together form a short triple helix chain. these are the molecules that leave the rough ER and are then trimmed at their ends to become tropocollagen
what is a fibripositor?
a special membrane tube in fibroblasts through which collagen fibrils are secreted which allows the collagen fibrils to be secreted in an organised direction which is important in tendons.
what is a key structural feature of elastin fibres
elastin fibres are cross linked together and have co-ordinated recoiling
what cells make elastin fibres?
fibroblasts, smooth muscle cells and chondroblasts
what is the function of proteoglycans?
they provide matrix support, cushioning and hydration, glue like function, links proteins of ECM and cell surface
what are the GAGs?
the brush-like fibres that from the side chains of the proteoglycans. They usually contain sulphate groups on the end of the polysaccharide chain which are highly charged and have a high affinity (they are negatively charged) for water molecules.
how do components of the ECM (like collagen fibres and proteoglycans) link to the cytoskeleton?
the ECM components link to an extracellular linking protein (e.g. fibronectin) which attached to intern which is a component of the plasma membrane which links to adaptor proteins which can attach to the cytoskeleton of the cell
what are myofybroblasts?
cells which secrete collagen fibres and actin, myosin and design fibres. after they have laid down these fibres they are embedded in the network or fibres and contract.
what goes wrong in Duchenne’s muscular dystrophy?
there is an absence of the adaptor protein (dystrophin) due to a genetic mutation. This leads to damage to the muscle fibres due to muscle tearing
what is ataluren?
an experimental drug used to treat duchesses muscular dystrophy which tries to allow the normal adaptor protein molecule to be synthesised
what are the key stages in the formation of a carcinoma?
the epithelial cells lose some junctions binding them together and start to bind to the basement membrane. invasion of the connective tissue is aided by the secretion of protease enzymes
