Flashcards
Extracellular Matrix Flash Cards
Cards in this deck (18)
- 1What are the types of extracellular matrix?- ultra thin tough sheets: separation and filtration e.g. basement membrane
- calcified: contains mechanical properties and strength e.g. bone
- unidirectional alignment: tensile strength e.g. tendon
- tightly woven 3D structure: resilient properties e.g. skin
- loose networks: allows free movement e.g. submucosa - 2What is the ratio of cells to extracellular matrix in adults and early embryos?early embryos: 80% cells and 20% extracellular matrix
adults: 20% cells and 80% extracellular matrix - 3What are the characteristics of the extracellular matrix?- genetic alteration in the ECM. results in a wide range of clinical conditions
- it transmits force
- a complex network of proteins and polysaccharides
- it is secreted locally be cells closely associated with it
- it provides structural support, adhesive and biochemical signalling support - 4What are the stages of ECM production and turnover?- deposition
- modification
- degradation (matrix metalloproteases) - 5What is ground substance?It fills the gaps between the fibres and the cells, it is hydrophilic, negatively charged and is good at absorbing water
- 6What is ground substance made up of?proteoglycans, glycoproteins and glycosaminoglycans
- 7What are glycosaminoglycans?GAGs are the carbohydrate components of proteoglycans, they are large molecules that attract water and link together with a core protein to form even larger molecules called proteoglycans
examples of GAGs: hyaluronic acid, chondroitin sulphate, keratin sulphate and heparan sulphate
[GAGs are mucopolysaccharides which means that they are chains of repeating disaccharide units] - 8What are proteoglycans?they are polysaccharides made up of a protein core + GAG, they are also known as mucoproteins and are mainly made up of carbohydrates, proteoglycans are made by fibroblasts where the protein core is synthesised on the RER while the GAGs are added in the Golgi and the substance is then delivered to the extracellular compartments by exocytosis
examples of proteoglycans: aggrecan, perlecan, syndical and decorin - 9What are glycoproteins?carbohydrate + protein
examples of glycoproteins: fibrillin, fibronectin, laminin, entactin/nidogen and tenascin - 10What are elastins?they are structural proteins arranged as fibres (structural glycoproteins) they are synthesised as tropoelastin, undergo hydroxylation and are coated in fibrillin
- 11What is the basement membrane composed of?type 4 collagen
it has 3 layers: lamina Lucida, lamina densa and lamina fibrorecticularis - 12What are some examples of problems that can occur in the ECM?- elastin: supravalvular aortic stenosis
- fibrillin-1: Marfan syndrome
- collagen: Elhers-Danlos syndrome
- keratan sulphatw: Macular corneal dystrophy
- perlecan: Silverman-handmaker type of dyssegmental dysplasia (DDSH) - 13How does the ECM prevent the overwhelming of cells with growth signals?it absorbs growth signals
- 14What makes up the fibrous component of the ECM?collagen, elastin and other
- 15What is the composition of collagen?it is synthesised as 3 polypeptides, a triple helix, glycine-X-Y where X and Y are hydroxyproleins, N-proteinase and C-proteinase cleaves peptides from collagen and it then assembles into collagen fibrils, collagen fibrils with lysysl oxidase forms covalent cross-links
- 16What are the main families of collagen?- fibril forming: tensile strength e.g. I, II, III
- FACIT and related: regulates fibril diameter and modifies fibril interactions
- hexagonal network forming: molecular sieves the provide planar support for cells
- endostatin-producing: regulators of cell migration and cell signalling
- anchoring fibrils: cell matrix interactions e.g. VII
- family of type IV
- type VI bead forming: elasticity and long range connectivity
- transmembrane cell matrix: important for interactions - 17What is osteogenesis imperfect?it is a collagen type 1 related disorder, autosomal dominant OI is a COL1A1 or COL1A2 mutation and it is a heterotrimeric protomer, OI has many glycine missense mutations due to the delay in folding resulting in overmodification
- 18What are the classes/types of collagen?I - fibrillar structure e.g. dermis, tendons, ligaments and bones
II - fibrillar structure e.g. hyaline cartilage
III - reticulin e.g. liver, bone marrow and lymphoid organs
IV - sheet/network e.g. basement membrane
V - linked to the basement membrane e.g. cornea
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- Year 1 Flashcards on Extracellular Matrix Flash Cards, created by Rana Al-Khayat on 20/05/2018.
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- Rana Al-Khayat
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