Normal Cartilage, and Bone

42 flashcards · Other · by Jared Blackwell

1. Perichondrium - Carries vasculature Cartilage - NO vessels, glossy.

2. Type II collagen Chondroblasts and chondrocytes Ground substance: Aggrecan aggregate Chondronectin

3. Describe the types of cartilage and where found?

   Elastic cartilage most flexible, ear, epiglottis. Hyaline nose, ribs, articular, trachea. Fibrocartilage - Knee and vertebrae, least flexible.

4. Lacuna Chondrocyte (inside lacuna) Matrix

5. Perichondrium Cartilage Chondroblasts Chondrocytes

6. Type II collagen in cartilage Limits expansion and tearing.

7. Aggrecan aggreagte - Ground substance. Shock absorb Aggrecan binds to hyaluronan to form large aggregates. Attract H2O and become turgid.

8. What does chondronectin do?

   Binds chondrocytes to type II collagen.

9. Describe the growth of cartilage

   Red: Appositional growth Chondroblasts deposit on outer surface - grows on outer edges. Blue: Interstitial growth Chondrocytes divide, deposit matrix - cartilage grows within. Green: Isogenous groups (clones).

10. Hyaline cartilage "glassy" Trachea, articular cartilage Costal cartilage, nose

11. Hyaline cartilage "glassy" Trachea, nose Costal ribs, articular cartilage

12. Elastic cartilage Epiglottis, pinna of ear Similar to hyaline but add elastic fibers.

13. Elastic cartilage Epiglottis, pinna of ear Add elastic fibers.

14. Fibrocartilage Add Type I collagen. Intervertebral discs, knees

15. Fibrocartilage Add Type I collagen. Intervertebral discs, knees

16. Synovium (red) Articular cartilage Joint capsule a

17. Synovial (joint) space Synovium

18. Describe the synovium

    Secretes synovial fluid. Intima secretes hyaluronan and digest debris. NO tight junctions or basement membrane Subintima: Leaky blood vessels.

19. Epiphysis Metaphysis Diaphysis Periosteum Endosteum Medullary (marrow) cavity Metaphysis Epiphysis

20. Compact (cortical) bone Trabecular (cancellous) bone Marrow cavity

21. Trabecular (cancellous) bone Compact (cortical) bone

22. Compact bone (green) Trabecular bone (blue)

23. What makes up the extracellular matrix of bone?

    Organic matrix - 30% Type I collagen Proteins Inorganic matrix - 70% Hydroxyapatite (hydroxylated calcium phosphate) 99% of total body calcium

24. What does the inorganic and organic bone matrix do?

    Inorganic matrix resists bending. Organic matrix makes bone tough, resist fractures.

25. Osteoblast Osteoprogenitor cells --> differentiate via BMPs Located in endosteum (green) and inner layer of periosteum. Secretes organic proteins to bone matrix.

26. Osteoclast Large, multinucleated, related to macrophages Digest bone matrix TRAP used as serum marker for osteoclast activity,

27. Periosteum where osteoblasts are; inner layer. -Also in endosteum

28. Endosteum- where osteoblasts are.

29. Explain the deposition of bone matrix

    1) Osteoblasts secrete organic proteins. 2) Inorganic matrix deposits onto organic matrix. calcium-binding proteins from osteoblasts promote deposits of calcium into matrix = mineralization.

30. Osteoid is organic matrix before it is mineralized.

31. Osteocyte Derived from osteoblasts. gap junctions extend through canaliculi. Respond to mechanical stress, bone remodeling.

32. Osteocyte Derived from osteoblasts. gap junctions extend through canaliculi. Respond to mechanical stress, bone remodeling.

33. Canaliculi - gap junctions extend through, osteocyte communication. Lacunae

34. Osteoblast Osteocyte Osteoclast

35. What does PTH and calcitonin do?

    PTH activates osteoclasts to raise calcium Calcitonin inhibits osteoclasts, allows osteoblasts to lower calcium.

36. Lamellar bone

37. Describe regulation of osteoblasts and osteoclasts

    Osteoblasts have RANK L which binds to RANK receptor on osteoclast precursor --> osteoclast. PTH increases RANK L and osteoclasts. OPG binds RANK L on osteoblast; SLOWS bone resorption. Calcitonin inhibits resoprtion and osteoclasts. Estrogen activates OPG which in turn blocks RANK L.

38. What does TGF-B do?

    It inhibits osteoclast resoprtion.

39. Describe the two types of bone development

    Flat Bones: Intramembranous ossification Mesenchymal cells differentiate into osteoblasts Osteoblasts deposit matrix directly into mesenchyme. Appositional Long Bones: Endochondral ossification Bone matrix deposited onto cartilage template. Growth in width is appositional. Growth in length occurs at epiphysis with cartilage growth, then replaced with bone.

40. Describe Endochondral ossification

    How long bones grow in length. Osteoblasts secrete a bone collar at sides. Chondrocytes in middle die. Angiogensis, osteoclasts/blasts come in. Osteoclasts remove cartilage and osteoblasts deposit bone.

41. Epiphyseal plate band of cartilage between primary and secondary ossification centers. If present, bone is still growing.

42. What is occuring?

    Left has epiphyseal plate then primary and secondary ossification centers fuse.