QUIZ 4 Bone: Structure and Function Flashcards Preview

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Flashcards in QUIZ 4 Bone: Structure and Function Deck (63)
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1

bone is composed as ___ overlaid on a ___ scaffold

  • hydroxyapatite
  • collagen I

2

what are the non-collagenous proteins found in bone?

  • bone sialoprotein (BSP)
  • osteopontin (OP)
  • osteocalcin (OC)
  • osteonectin (ON)
  • matrix extracellular phosphoglycoprotein

3

bone is ___% inorganic and ___% organic

  • 67
  • 33

4

describe the organic component of bone

  • 33% of overall bone composition
  • 28% collagen, 5% noncollagenous proteins

5

what are the physiological roles of bone?

  • structural
  • calcium homeostasis (9-10 mg/dL)
  • reservoir for growth factors in tissue repair
  • contains both hematopoietic and mesenchymal progenitor cell populations in marrow

6

describe the macrostructure of bone

  • outer layer of dense compact (cortical) bone, with an inner cavity
  • inner cavity contains marrow (red or yellow) and cancellous (trabecular) bone
  • bone is highly vascular with a network of blood vessels

7

describe the macrostructure of compact bone

 

  • 3 organizational units
    • circumferential - outer ring of bone tissue
    • concentric (osteonic) lamellae - intact osteons
    • interstitial lamellae - fill space between concentric lamellae; former concentric lamellae

8

the ___ is the basic functional unit of compact bone

osteon

9

___ connect haversian canals, linking osteons

volkmann's canals

10

describe osteons

  • form cylinders running parallel to the long axis of a bone
  • formed from concentric lamellae
  • concentric rings of bone, built around a canal housing a capillary (haversian canal)

11

___ is found at the ends of long bones, in apposition to joints and is associated with the marrow spaces

cancellous bone

12

what is the function of cancellous bone?

provides structural support for marrow tissues, and is highly vascular

13

cancellous bone is the site of ___ production, and also supports ___ and ___ progenitor cell populations

  • blood cell
  • mesenchymal and hematopoietic

14

what is the periosteum?

  • connective tissue layer attached to the outer surface of a bone by sharpey's fibers
  • consists of two layers - outer fibrous layer and inner layer in apposition to the bone surface
    • the inner layer is both highly cellular and highly vascularized

15

what is the endosteum?

  • loose connective tissue covering the inner surface of both cancellous and compact bone
  • separate the marrow from the bone
  • poorly defined histologically

16

what are the 3 bone cells, and what are their functions?

  • osteoblasts - bone forming cells with a mesenchymal origin
  • osteocytes - bone cells; encapsulated osteoblasts (also mesenchymal in origin)
  • osteoclasts - cells that break down bone tissue; hematopoietic origin

17

the carefully regulated interactions between osteoblasts, osteocytes, and osteoclasts is responsible for ___, ___, and ___

bone formation, repair, and maintenance

18

___ are mononucleated cells which synthesize osteoid matrix

osteoblasts

19

osteoblasts arise from ___

mesenchyme (ectomesenchyme in the head)

20

osteoblasts differentiate in response to a cascade of ___

growth factors

21

osteoblasts have a role in both ___ and ___

bone formation and repair

22

osteoblasts communicate with each other through ___

gap junctions

they do not form complexes

23

what do osteoblasts produce? what do they secrete?

  • produce osteoid matrix, similar to odontoblasts
  • produce AND secrete collagen, non collagenous proteins via vesicles
  • secrete growth factors into osteoid matrix, where they are sequestered (TGF-beta-1, BMP2, IGF I and II, PDGF, FGF)

24

after bone formation, ___ flatten and form bone lining cells

osteoblasts

25

___ are osteoblasts that embed themselves into bone matrix

osteocytes

26

the terminal differentiation for osteoblasts in what cell?

osteocytes

27

osteocytes form ___ in bone tissue

interconnected lacunae

28

osteocytes have cellular processes which interact with surrounding bone tissue.  describe this.

  • mechano-transduction
  • coordination of odontoblast/osteoclast activity
    • mechanical forces → osteocyte stimulates osteoblast and osteoclast activity

29

___ are large multi-nucleated cells that are a fusion of monocytes

osteoclasts

30

___ are responsible for the resorption of bone

osteoclasts