ECM Flashcards by tcarlso 3

What are the three basic ground elements of the ECM?

Ground substance
Fibers
Granulation tissues

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What are the characteristics of the ground substance of the ECM?

amorphous, tranparent, colorless, and homogenous

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What are the functional attributes of the ECM?

Structure
Defense
Nutrition
Diffusion of gases, molecules, ions
Cell growth, survival
Cell migration
Lubrication

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Where is lubrication used?

cartilage (joints)

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What does the ground substance include?

GAGs (= mucopolysaccharides)

Proteoglycans

Water

Adhesive glyoproteins

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What are the constituents of the fibers?

Collagen

Reticular (type III collagen)

Elastic

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What are the two type of cell repair?

Granulation tissue (replacing dead cellswith ECM) (scar)

Replace functional tissue

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How does the ECM drive the cell cycle?

Senses points of contact, such that more contacts will increase prb of growth

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What is the probability of a cell suspended in agar of entering S phase?

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What determines if a tissue will replace damage with scar tissue or cells?

Whether or not the ECM is damaged–if it is not, then replace with cells.

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What causes the attraction of water to GAGs?

Carboxyl groups

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What are the six types of GAGs?

Dermatan sulfate
Chondrotin sulfate
Heparan sulfate
Keratan sulfate
Hyaluronic acid
Heparin

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What causes the increased hydration of tissue behind the eyes in grave’s disease?

Chrondroitin sulfate and hyaluronic acid deposition

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What is the structure of proteoglycans?

Thistle brush

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What is the backbone of proteoglycans? Branches?

Hyluronic acid

GAGs are branches

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What is syndecan?

Transmembrane proteoglycan that connects FGF receptors via GAG branches (coreceptor for fibroblast growth factor)

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What is perlecan?

Proteoglycan present in the basement membrane of tissues involved in proliferation, differentiation etc.

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Inactivation of perlecan results in what?

Skeletal dysplasia

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What are the 3 typical binding domains for multiadhesie glycoproteins?

cell adhesion molecules (CAMs, e.g. integrin)
Collagen fibers
Proteoglycans

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Over hydration of the ground substance leads to what?

Edema

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The ground substance fill space between what and what?

Cells and fibers

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What are proteoglycans?

Linear chains of glycosaminoglycans bound to a protein core form proteoglycans

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What percent of the molecular weight of a proteoglycan is due to carbs?

80-90%

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What are glycosaminoglycans?

Long chains of unbranched poly saccharides consisting of a repeating disaccharide unit

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What is the substance that forms the "core" of the proteoglycans?

Hyaluronic acid

What are the function of perlecans?

``` Cell adhesion Cell proliferation Cell differentiation Glomerular filtration Development Growth factor binding ```

What is the probability of a cell dividing when it is perched on a small adhesive patch?

30%

What is the probability of a cell dividing when it is perched on a LARGE adhesive patch?

90%

When GAGs form a bond with Hyluronic acid, what does it then become?

Aggregans

What is a major consequence of aggregan formation?

Increases hydration state

What are aggregans attached to?

Type I collagen

What are multiadhesive glycoproteins?

are glycoproteins that molecularly tether the cell to extracellular elements

What are the three primary binding sites for multiadhesive glycoproteins?

one for integrins (cell adhesion molecules), one for collagen fibers, and one for proteoglycans

What is the binding domain and location of fibronectin?

BInds to integrins, collagen, heparin, heparan sulfate, hyaluronic acid Location = connective tissue, blood plasma, and embryonic tissue

What is the binding domain and location of Laminin?

Binds to integrins, heparane sulfate, collagen IV, and entactin Found in the basal lamina

What is the binding domain and location of Tenascin?

Binds to syndecans and fibronein Location = basal lamina

What is the binding domain and location of chondronectin?

Binds to collagen, II, chondroitin sulfates, hyaluronic acid, integrins of chondrocytes Location = carilage

What is the binding domain and location of osteonectin?

Binds to collagen, proteoglycans, and integrins of bone cells Location = bones

Blocking fibronectin blocks what important development process in mice?

mophogenesis

What is the most abundant protein in the body?

Collagen (20-25% of all protein)

What are the three major amino acids that make up collagen?

Glycine, hydroxyproline, hydroxylysine

Where is type I collagen found?

Dermis, tendon, bone, dentin, cementum, fibrocartilage, organ capsules

Where is type II collagen found?

Hyaline and elastic cartilage

Where is type III collagen found?

Spleen, liver, lymph nodes, smooth muscle, skin, lung

Where it type IV collagen found?

Basal lamina

Where is collagen I synthesized?

Fibroblasts, odontoblasts, cementoblasts, osteoblats, chondroblasts

Where is collagen II synthesized?

Condroblasts

Where is collagen III synthesized?

Smootuh muscle cells, fibroblasts, reticular cells

Where is collagen IV synthesized?

Endothelial cells, epithelial cells, schwann cells, smooth muscle cells

What is the function of type I collagen?

Resists tension

What is the function of type II collagen?

resistes pressure

What is the function of type III collagen?

maintains structure in expansible organs

What is the function of type IV collagen?

Supports delicate structures Filtration

what is the molecular organization of type I collagen?

Fibril-forming collagen leading to the formation of fibers

what is the molecular organization of type II collagen?

Fibril-forming collagen

what is the molecular organization of type III collagen?

Fibril-forming collagen leading to the formation of fibers

what is the molecular organization of type IV collagen?

Network-forming collagen

Where is type VII collagen found?

Dermis

What types of cells synthesize type VII collagen?

epidermal cells

What is the function of type VII collagen?

anchors the lamina densa to the lamina reticularis

What is the molecular organization of type VII collagen?

Anchoring collagen

What amino acid is measured to calculate the [C] of collagen?

Hydroxyproline

Is collagen acidophilic or basophilic?

Acidophilic

What are the two means collagen can be degraded?

Proteolytic | Phagocytic

Trichrome methods will color collagen what color?

Blue

Reticular fibers are composed of what?

Type III collagen

What do reticular fibers stain with?

Argyrophilic (silver) and PAS

What types of cells synthesize retiular fibers?

fibrocytes, reticulocytes, smooth myocytes, and schwann cells

True or false: reticular fibers branch?

True

What is the function of elastic fibers?

Imparts tissue with elasticity

Which stain would you use to highlight elastic fibers?

Verhoeff or resorcin-fushsin

How are elastic fibers arranged?

b. Densely arranged in bundles (ligamentum flavum)

What are the three components of elastic fibers?

Proelastin (contains a.a. desmosine and isodesmosine) Microfibril-associated glycoproteins Fibrillin (1 and 2)

Which amino acids are unique to the ECM?

Desmosine and isodesmosine

What is the defect and clinical relevance of Ehlers-Danlos type 4?

Mutation in the COL3A1 gene encoding type III collagen (reticular fibers) Varicose veins, aortic rupture, intestinal rupture

What is the defect and clinical relevance of Ehlers-Danlos type 6?

Defective hydroxylation of lysine thereby destabilizing the strength of the collagen Hyperelasticity of the skin, rupture of the eyeball

What is the defect and clinical relevance of Ehlers-Danlos type 7?

Mutations in the COL1A1 and COL1A2 genes encoding type I collagen Joint dislocation and hypermobility of joints

What is the defect and clinical relevance of osteogenesis imperfecta?

Mutations in COL1A1 lead to a reduction in the synthesis of type I collagen Spontaneous fractures and cardiac insufficiency

What is the defect and clinical relevance of strickler syndrome?

Mutation in COL2A1 gene encoding for type II collagen Myopia, hypoplasia of mandible, arthritis

What is the defect and clinical relevance of Marfan syndrome?

Mutation of the fibrillin 1 gene located on chromosome 15 Aortic aneurysm or rupture, myopia, detached lens, skeletal defects (long, thin arms, legs, toes, and fingers; pectus excavatum; scoliosis

What is the defect and clinical relevance of scurvy?

Tropocollagen molecules cannot aggregate into fibrils due to decreased hydroxylation of proline caused by a deficiency in vitamin C Gum ulceration and hemorrhages

Where is the basal lamina found?

Epithelium Kidney glomerulus Muscle cells

What are the components of the basal lamina?

Lamina lucida | Lamina densa

What is the composition of lamina lucida?

Laminin, entactin, integrins, dystroglycans

What is the composition of the lamina densa?

Type IV collagen, fibronectin, and perlecan

What are the components of the basemen membrane?

Basal lamina + lamina fibronreticularis

What is the composition of the lamina fibroreticularis?

Fibronectin and types I and III collagen

What type of collagen serves to anchor the lamina densa and lamina fibroreticularis?

VII

How does membranous nephropathy come about?

Anitbodies attacking the basement membrane of the kidneys

Observing a sample of kidney cells stained with silver methenamine through a light microcope, you see small, black projections coming off of the cells. What is your diagnosis?

Membranous nephropathy