Ch. 6 Skeletal System Flashcards

1
Q

Describe the matrix of bone

A
  1. 2% bone cells (osteocytes) within lacunae
  2. 2/3rds calcium phosphate
  3. 1/3 collagen fibers
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2
Q

lacunae

A

the space occupied by either osteocytes or chondrocytes

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3
Q

canaliculi

A
  • narrow pasageways through matrix for the exchange of nutrients, waste, and gases
  • contain cytoplasmic extensions of osteocytes
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4
Q

what type of bone does not have a periosteum?

A

joints/articulated

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5
Q

hydroxyapatite

A
  • crystals formed from the interaction fo calcium phosphate and calcium hydroxide
  • incorporate other calcium salts as they form
  • withstand compression, but not bending or sudden impacts
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6
Q

describe the composition of spongy bone

A
  • collagen fibers form a framework for hydroxyapatite crystals to form.
  • Crystals form small plates and rods locked into collagen fibers at regular angles
  • Resulting protein-cystal combination has flexibility of collagen with compressive strength/shatter resistance
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7
Q

What are the 4 cells of bone?

A
  1. osteocytes
  2. osteoblasts
  3. osteoprogenitor cells
  4. osteoclasts
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8
Q

osteocytes

A
  • Mature bone cells
  • only in lacunae, between lamellae
  • extend through canaliculi and link by gap junctions
  • Do not divide

Functions:

  1. To maintain protein and mineral content of matrix
  2. To help repair damaged bone
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9
Q

lamellae

A

layers of matrix that separate osteocytes

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10
Q

ossification; osteogenesis

A

the production of new bone matrix by osteoblasts

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11
Q

osteoid

A
  • the organix matrix secreted by osteocytes before calcium salts are deposited and becomes ‘bone’
  • osteoblasts elevate local calcium concentrations above solubility, triggering deposition in the organic matrix
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12
Q

osteoblasts

A
  • Make and release proteins and other organic components of matrix (osteoid)
  • trigger calcium deposition to form bone
  • develop into osteocytes when surrounded by bone matrix
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13
Q

osteoprogenitor cells

A
  • Squamous (mesenchymal) stem cells
  • differentiate into osteoblasts
  • located in endosteum
    • medullary cavities
    • passageways of compact bone matrix
  • assist in fracture repair
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14
Q

osteoclasts

A

– Secrete acids and protein-digesting enzymes

– Giant, multinucleate cells (50 or more!)

– Dissolve bone matrix and release stored minerals
(osteolysis)

– Derived from stem cells that produce macrophages

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15
Q

osteolysis (resorption)

A

acids and proteolytic enzymes secreted by osteoclasts dissolve the matrix and release stored minerals

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16
Q

What are the five functions of the skeletal system?

A
  1. Support
  2. Storage of minerals and lipids
  3. Blood cell production
  4. Protection
  5. Leverage
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17
Q

What is stored in bone?

A
  1. calcium
  2. phosphate ions
  3. yellow bone marrow (lipid energy reserves)
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18
Q

What are the 6 categories of bone shape?

A
  1. Sutural bones (Wormian bones)
  2. Irregular bones
  3. Short bones
  4. Flat bones
  5. Long bones
  6. Sesamoid bones
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19
Q

Sutural bones

(Wormian bones)

A
  • Small
  • Flat
  • Irregular shape

Between the flat bones of the skull. Jigsaw puzzle.

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20
Q

Irregular bones

A
  • Complex shape
  • Short, flat, notched or ridged

Location: Spinal vertebrae, bones of pelvis, some skull bones

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21
Q

How are bones classified?

A
  1. Shape
  2. Internal tissue organization
  3. Bone markings
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22
Q

Short bones

A

small and boxy

Ex: carpal and tarsal bones

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23
Q

Flat bones

A

thin, parallel surfaces. Provide protection for underlying soft tissuse and extensive surface area for muscle attachment

Ex: roof of skull

sternum

ribs

scapulae

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24
Q

Long bones

A

Long and slender

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25
Q

Sesamoid bones

A

small, flat and shaped like sesame seeds

develop inside tendons

commonly located near joints; vary between individuals

Ex: Patella

26
Q
  • Small
  • Flat
  • Irregular shape

Between the flat bones of the skull. Jigsaw puzzle.

A

Sutural bones

(Wormian bones)

27
Q
  • Complex shape
  • Short, flat, notched or ridged

Location: Spinal vertebrae, bones of pelvis, some skull bones

A

Irregular bones

28
Q

small and boxy

Ex: carpal and tarsal bones

A

Short bones

29
Q

thin, parallel surfaces. Provide protection for underlying soft tissuse and extensive surface area for muscle attachment

Ex: roof of skull

sternum

ribs

scapulae

A

Flat bones

30
Q

Long and slender

A

Long bones

31
Q

small, flat and shaped like sesame seeds

develop inside tendons

commonly located near joints; vary between individuals

Ex: Patella

A

Sesamoid bones

32
Q

diaphysis

A

extended tubular shaft of a long bone

33
Q

epiphysis

A

expanded area of the long bone

34
Q

metaphysis

A

the narrow zone that connects the diaphysis and epiphysis

35
Q

dense bone

A

the layer of compact bone that makes up the wall of the diaphysis

36
Q

compact bone

A
  • forms a sturdy protective layer that surrounds the medullary cavity
  • All osteons are aligned in the same direction
37
Q

medullary cavity

A

marrow cavity; the central space in long bones

38
Q

cancellous; trabecular bone

A

spongy bone that makes up the epiphyses

39
Q

spongy bone

A
  • The matrix forms an open network of struts and plates (trabeculae) that resemble latticework
  • Does not have osteons
  • Trabeculae have no blood vessels
  • The space between trabeculae is filled with marrow
40
Q

cortex; cortical bone

A

the thin covering of compact bone over spongy bone

41
Q

Diploë

A

the spongy bone structure (or tissue) of the internal part of short, irregular, and flat bones.

Although red bone marrow is present, there is no large medullary cavity

42
Q

osteon, Haversian system

A

the basic unit of mature compact bone

Key Features:

  • concentric lamellae
  • central (Haversian) canal
  • perforating (Volkmann’s) canals
43
Q

Haversian canal

A
  • central canal
  • contains one or more blood vessels
  • generally parallel to surface of bone
44
Q

Volkmann’s canals

A
  • perforating canals
  • perpindicular to surface
  • supply blood to deeper osteons and medullary cavity
45
Q

concentric lamellae

A

layers of matrix that extend outward from the central canal

46
Q

interstitial lamellae

A
  • layers of matrix that fill spaces between osteons in compact bone
  • remnants of recycled osteons
47
Q

circumferential lamellae

A
  • found at the outer and inner surfaces of bone
  • covered by periosteum (outer) or endosteum (inner)
48
Q

layers of matrix that extend outward from the central canal

A

concentric lamellae

49
Q
  • layers of matrix that fill spaces between osteons in compact bone
  • remnants of recycled osteons
A

interstitial lamellae

50
Q
  • found at the outer and inner surfaces of bone
  • covered by periosteum (outer) or endosteum (inner)
A

circumferential lamellae

51
Q
  • central canal
  • contains one or more blood vessels
  • generally parallel to surface of bone
A

Haversian canal

52
Q
  • perforating canals
  • perpindicular to surface
  • supply blood to deeper osteons and medullary cavity
A

Volkmann’s canals

53
Q

trabeculae

A

fiber bundles composed of matrix that create the supporting meshwork of spongy bone

54
Q

fiber bundles composed of matrix that create the supporting meshwork of spongy bone

A

trabeculae

55
Q

red bone marrow

A

fills the space between trabeculae

  • has blood vessels
  • forms red blood cells
  • supplies nutrients to osteocytes through canaliculi
56
Q

yellow bone marrow

A

fills space between trabeculae in some spongy bone; stores fat

57
Q

Weight-Bearing bone

at the femur transfers weight from the _______ to the ________

causing ______ on the lateral side of the diaphysis and ______ on the medial side

A
  1. Hip-joint
  2. Knee joint
  3. Tension
  4. Compression
58
Q

Functions of periosteum

A
  1. Isolates bone from surrounding tissues
  2. Provides route for circulatory and nervous supply
  3. participates in bone growth and repair

Note:

  • articulated joints: continuous with connective tissues that lock bones together
  • synovial joint: continuous with joint capsule
59
Q

Sharpey’s fibers

A
  • Perforating fibers
  • collagen fibers incorporated into bone tissue from tendons and ligaments, or superficial pereosteum
60
Q

endosteum

A
  • active during bone growth, remodeling, repair
  • lines medullary cavity, trabeculae of spongy bone and inner surfaces of central canals
  • simple, flattened layer of osteoproginetor cells without intervening connective tissue fibers
  • where layer is incomplete, matrix is exposed. Osteoclasts and osteoblasts remove or deposit matrix at these openings.
61
Q

osteoclastic crypts

A

shallow depressions that have eroded into the matrix exposed to the endosteum