Chapter 5 skeletal

  1. What is the skeletal systems supporting connective tissue?
    • Bones
    • Cartilage
  2. What is the skeletal systems dense connective tissue proper?
  3. What is the function of the bones?
    • Support the body
    • Storage for minerals and lipids (98% calcium, marrow)
    • Blood cell production
    • Protection (ribs, skull, pelvis?
    • Leverage (change magnitude & direction of muscle)
  4. What are bones?
    • Dynamic
    • Complex organs
  5. What is bone tissue made of?
    • Supporitng connective tissue
    • Specialized cells
    • Matrix
  6. What does the bone matrix consist of?
    • Calcuim salts on 2/3 collagen fibers
    • Strong solid matrix (withstand compression)
  7. Name the cells of bone tissue?
    • Osteoprogenitor cells
    • Osteoblasts
    • Osteocytes
    • Osteoclast cells
  8. What are osteoprogenitor cells? What is their function?
    • Mesenchymal cells
    • Mitosis & differentation (daughter cells) repair
    • & regrowth
  9. What do daughter cells become?
  10. What is the function of osteoblasts?
    • Produce new bone (secrete bone matrix)
    • Becomes mineralized, may respond to
    • Mechanical or hormonal stress to
    • Initate osteogensesis
  11. What are osteocytes? What is their function?
    • Mature bone cells
    • Maintain the matrix (dynamic)
    • Controls release of calcium to the blood
    • & depositing of Ca++ salts in the matrix
  12. What is a chamber, or cave within an osteocyte?
  13. What are the layers in an osteocyte called?
  14. Within the osteocyte, what are the channels called?
  15. What is the purpose of the canaliculi?
    • Connects to blood supply inside or outside
    • Their are gap junctions between them
  16. What is the function of the osteoclast cells?
    • Dissolve bone matrix
    • & release Ca++ to blood
  17. At a young age which is more active osteoblasts or osteoclast cells?
    Osteoclast cells
  18. What are the two types of bone matrix?
    • Compact
    • Spongy
  19. How does the spongy bone look? What is the function?
    • Open framework (struts)
    • Forms marrow
    • Lighter
  20. What will trabeculae do in the spongy bone if stressed?
    Align themselves to support the bone
  21. What is the quaility of the compact bone? What is the function?
    • Dense & solid
    • Forms walls of bones
    • Osteon
    • Thicker at high stress areas
  22. What is a osteon?
    Functional unit of mature compact bone
  23. In an osteon, where are the osteocytes & matrix found?
    In concentric circles around central canal
  24. In an osteon where do the canaliculi interconnect?
    The lacunae
  25. Name and define the three parts of the long bone?
    • Epiphysis-end
    • Metaphysis-transition
    • Diaphysis-shaft
  26. What does physis mean?
  27. Name the layers of the bone?
    • Periosteum membrane
    • Compact bone
    • Spongy bone
    • Endosteum
    • Marrow
  28. What is the periosteum membrane? What is it's function?
    • Outside surrounds the bone
    • Necessary for bone growth and repair
    • Attachement
  29. Where is the marrow located?
    Inside the endosteum
  30. What is the endosteum? It's function?
    • Thin layer of connective tissue
    • Lines the surfaces of bony tissue
    • That forms the medullary cavity
    • Active in growth and repair
  31. Which cells are present in the endosteum?
    • Osteoprogenitor cells
    • Osteoblasts
    • Osteoclast cells
  32. Define ossification?
    Replacing other tissue with bone tissue
  33. What is the process of ossification in a human embryo 'skeleton'?
    • Fibrous connective tissue (mesenchymal cells)
    • & hyaline cartilage loosely shaped like bones
    • Undergo ossification to become bones
  34. When does ossification begin?
    6-7 week embryo (1/2 inch long)
  35. Name the two ways ossification can occur?
    • Intramembranous (within a membrane)
    • Endochondral (within a cartilage)
  36. What bones are the outcome of intramembranous ossification?
    • Skull
    • Jawbone
    • Collar bone
    • Patella
    • (flatbones)
  37. What is the process from beginning to end of intramembranous ossification?
    • Ossification centers begin in
    • Fibrous connective tissue
    • (meschymal cells differentiate into osteoblasts)
    • These center secrete matrix which undergoes
    • Calcification and center gets larger
    • The bone becomes spongy bone and then produces
    • The outer compact bone
  38. What are fontanels?
    • Soft spots
    • Membrane left that is not ossified
  39. Describe the endochondral ossification process?
    • Cavities form in the cartilage model by
    • Bursting chondrocytes
    • A bone collar is formed around the shaft of the model by
    • Osteoblasts. Blood vessels penetrate the collar
    • & cartilage and enter the central cavity and bring osteoblasts
    • That produce spongy bone. The bone shaft becomes thicker
    • Capillaries enter epiphysis bringing osteoblasts
    • That create secondary ossification centers
  40. How are most bones formed?
    Through endochondral ossification
  41. What is a chondrocyte?
    The only cells found in cartilage
  42. How are osteocytes important to bone maintenance?
    • They are continually removing &
    • Replacing calcuim salts
  43. How much of the adult skeleton is demolished and rebuilt, or replaced each year?
  44. What two bone cells remain active throughout our lives?
    • Osteoblast
    • Osteoclast cells
  45. When does bone growth occur?
    • When osteoblasts are creating more
    • Matrix then osteoclast cells are removing
  46. What is true for the bone cells of older individuals?
    • Osteoclast cell activity is
    • Higher than osteoblasts
  47. What is osteoporosis?
    The result of too little mineralization of bones
  48. What is linked to osteoporosis?
    • Deficiency of mineral in youth
    • Loss of estrogen at menopause
    • Imbalance of activity of osteoblasts and osteoclasts
Card Set
Chapter 5 skeletal
Skeletal system