4.14.2010 lecture 2

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4.14.2010 lecture 2

  1. 1. 4.14.2010 Lecture 2 - ECM<br /><ul><li>Tissue Types
  2. 2. There are four tissue types
  3. 3. Muscle Tissue
  4. 4. Smooth Muscle
  5. 5. Cardiac Muscle
  6. 6. Striated Muscle
  7. 7. Nervous System Tissue
  8. 8. Neuronal cells
  9. 9. Non-neuronal cells
  10. 10. Connective Tissue
  11. 11. Bone
  12. 12. Osteocytes
  13. 13. Mature bone cells
  14. 14. Precursor is the osteoblast
  15. 15. Secretes ECM during development of that tissue
  16. 16. Cartilage
  17. 17. Condroblasts
  18. 18. Secrete ECM
  19. 19. Loose connective Tissue
  20. 20. Fibroblasts
  21. 21. Secrete ECM
  22. 22. Blood
  23. 23. Lymphoid Tissue
  24. 24. Made by cells
  25. 25. Undifferentiated form of the mature cells that are characteristic of that tissue type
  26. 26. Epithelial Tissue
  27. 27. Epithelia
  28. 28. Epithelial Cells
  29. 29. Skin
  30. 30. Intestinal Lining
  31. 31. Held to one another and to the basal lamina
  32. 32. Held to one another by tight junctions and adherins junctions
  33. 33. Linked to basal lamina by integrins
  34. 34. Integrins interact directly with the ECM
  35. 35. Needs of basal lamina
  36. 36. Loose connective tissue
  37. 37. This is where we see the most gel-like structure in this type of connective tissue
  38. 38. Fibroblasst secrete LCT
  39. 39. Collagen
  40. 40. Elastin
  41. 41. Proteoglycans (more gel-like)
  42. 42. Glycoproteins (more gel-like)
  43. 43. Use intermediate filaments that are connected to the junctions between the cells and with the cell interaction between the basal lamina to withstand stress
  44. 44. Connective Tissue Macromolecules
  45. 45. ECM is made of two types of macromolecules
  46. 46. Proteoglycans
  47. 47. Protein core, which can vary, surrounded by GAGs
  48. 48. Glycosomino Glycans
  49. 49. They are negatively charged repeating units of sugars, polysaccharides, that covalently link themselves to the protein core, and useful in forming ECM because – charge attracts H20, creating a buffering sort of tissue that can withstand tensile stress and create a hydrated environment so cells can move and nutrients and waste can diffuse through and the cells can function because of those mobile molecules. Also cell motility
  50. 50. Can link in complex ways
  51. 51. The more GAGs, the more water and the more flexible that connective tissue is
  52. 52. Fibrillar
  53. 53. Types
  54. 54. Collagen
  55. 55. Fibronectin
  56. 56. Elastin
  57. 57. Importance
  58. 58. Strong Structures
  59. 59. Strength to the ECM
  60. 60. Organization to the ECM
  61. 61. Cell-ECM interaction
  62. 62. From organized structure of ECM, allowing ECM to withstand pressure
  63. 63. Holds tissue together when there is change or mechanical stress on the tissue
  64. 64. Collagen
  65. 65. Rheumatoid arthritis
  66. 66. Inflammatory response, autoimmune, that is though to be genetic
  67. 67. Immune system attacks collagen in ECM
  68. 68. Unknown
  69. 69. Causes pain and disfiguring of the joints
  70. 70. Made of alpha chains
  71. 71. Can assemble in a variety of ways
  72. 72. Results in the types of collagen made
  73. 73. Types of Collagen
  74. 74. Type I – Fibrillar type
  75. 75. 90% of ECM of the body
  76. 76. Types can be differentiated by the roman numerals. Types can be placed into functional group:
  77. 77. Fibrillar Forming collagen
  78. 78. Fibril Associated collagen
  79. 79. Network forming collagen
  80. 80. Transmembrane collagen
  81. 81. Synthesis of Collagen - ER
  82. 82. Formed by the synthesis of an alpha chain
  83. 83. Amino acid structure varies
  84. 84. All have high concentrations of proline and glycine amino acids
  85. 85. Proline: becomes heavily hydroxylated as the chain forms
  86. 86. Form H bonds with neighboring amino acids
  87. 87. Helps hold alpha chains together
  88. 88. Glycine
  89. 89. Smallest amino acid
  90. 90. Present every third amino acid so the chains can interact very closely and tightly
  91. 91. Three alpha chains fold together to make a procollagen triple helix, still in the ER
  92. 92. On either end of the procollagen, amino acids hang off of amino and COOH termini
  93. 93. Eventually clipped, which allows continual assembly
  94. 94. Cannot occur until procollagen is secreted into cytoplasm
  95. 95. Procollagen peptidase cleaves of terminal amino acids to make a mature collagen molecule ready to form into the fibril and fiber forms
  96. 96. Assembly
  97. 97. Procollagen align with one another with overlapping regions
  98. 98. Creates striated pattern in the fibrillar collagen and allows for strength of collagen fiber in mature state
  99. 99. Collagen fiber is generated as fibril wind around one another (~270 of collagen molecules that make up the fibril before the fiber)
  100. 100. Occurs in cytoplasm after terminal amino acids are cleaved
  101. 101. Types of Collagen
  102. 102. Type I
  103. 103. Fibrillar and associated collagen molecule (type 6)
  104. 104. Type 6 – collagen regions, in between is a globular domain, which allows flexibility
  105. 105. Purpose of flexibility: strength of fiber and flexibility of collagen associated protein
  106. 106. Makes a strong fiber less rigid and more flexible
  107. 107. Proteoglycan associates with the fibrils and carries with it the GAGs and water molecules, creating a buffer and gel like substrate for the absorption of force
  108. 108. Bone
  109. 109. Type II
  110. 110. Cartilage
  111. 111. Associated with non-fibrilar collagen, type IX
  112. 112. Type IX has globular repeating units that interact with the fibrilar collagen
  113. 113. Has a kink so amino terminus protrudes into ECS
  114. 114. Organizes collagen fibers in cartilage
  115. 115. Instead of aligned, they criss-cross one another
  116. 116. More space = more proteoglycans and water
  117. 117. Provides more flexibility to collagen, unlike bone
  118. 118. Diseases/Mutations in Collagen
  119. 119. Hydroxylated states of proline
  120. 120. Scurvy
  121. 121. Caused by a deficiency in vitamin C
  122. 122. Teeth fall out
  123. 123. Joints hurt
  124. 124. All types of collagen break down because the deficiency causes a decrease in the ability of the cell to hydroxylate proline
  125. 125. Less interaction of collagen and the assembly in the cytoplasm doesn’t take place
  126. 126. Teeth not connected
  127. 127. Type I mutation
  128. 128. Affects bone tissue
  129. 129. Osteogenesis Imperfecta
  130. 130. Brittle bones
  131. 131. Unbreakable movie
  132. 132. Type II mutations
  133. 133. Cartilage
  134. 134. Condro displagia
  135. 135. Abnormal joint formation and structure and function due to mutation
  136. 136. Abnormal cartilage formation
  137. 137. Type III
  138. 138. ECM
  139. 139. Ailers Danlow Syndrome
  140. 140. Fragile skin
  141. 141. Disruption in basal lamina
  142. 142. Affects blood vessel strength (weak BVs)
  143. 143. Hypermobile joints because tendons are very loose
  144. 144. Recurrent joint dislocation and swelling
  145. 145. Ruptured blood vessels
  146. 146. Blister easily
  147. 147. Fibronectin
  148. 148. Fibrillar macromolecule
  149. 149. Secreted by fibroblasts in the connective tissue
  150. 150. Made of two polypeptides linked together at COOH terminus by disulfide bonds
  151. 151. When secreted, has multiple roles because it has different regions that do different things
  152. 152. Fibrin and heparin binding domains
  153. 153. Sites where fibronectin molecules is associate with blood clot processes
  154. 154. Helps induce reaction to blood clot formation
  155. 155. Cell surface receptor binding domain
  156. 156. RGD sequence – three amino acids
  157. 157. Arginine, glycine, aspartate
  158. 158. Important for interacting with cells in ECM
  159. 159. Links with integrin receptors specifically in the PM
  160. 160. Bind to fibronectin in the ECM
  161. 161. If cell is on top of ECM, integrin poke down into ECM and interact with firboncetin at that particular site
  162. 162. Collagen binding domain
  163. 163. Allows fibronectin to interact with collagen and help organize ECM
  164. 164. Interacts on PM with integrin receptors and the FN out in the environment
  165. 165. Integrins transduce signals to the inside of the cells and link to the actin cytoskeleton
  166. 166. As integrin binds to actin, actin will grow, so integrins help develop the structure of the cell
  167. 167. Cells use these cues to move through environment
  168. 168. Allows organization of cytoskeleton
  169. 169. Allows functioning properly in the tissue types

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