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