Ch.6 The Skeletal System: Bone Tissue Flashcards

1
Q

Function of Bone Tissue

A
  1. Support (frame work, scaffolding for the soft tissue)
  2. Protection (surround soft tissue to prevent injury)
  3. Movement (act as levers for muscle to work on)
  4. Mineral storage (calcium, magnesium, and phosphate are deposited and withdrawn)
  5. Blood cell formation (all blood cells and platelets are made in red marrow cavities)
  6. Triglyceride storage (fats are stored in yellow marrow)
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2
Q

Connective tissue

A
  • Associated with cartilage, blood, and fat
    Two types of bone:
    1. Spongy= 20 % of all bone, network of bone pieces with open spaces visible
    2. Compact = 80% of bone smooth and solid looking
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3
Q

Types of Bone

A
  1. Lone Bone
  2. Irregular Bone
  3. Flat Bone
  4. Short Bone
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4
Q

Long Bone

Type of Bone

A
  • Longer than wide
  • shaft with two ends
  • have a diaphysis and epiphysis
  • external is compact bone, internal is spongy
  • Ex: most all appendicular bones –> humerus
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5
Q

Irregular Bone

Type of Bone

A
  • Complicated shapes
  • if doesn’t fit other categories
  • Ex: vertebra and hip bone
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6
Q

Flat bone

Type of Bone

A
  • Thin, flattened and a bit curved
  • thin external coat of compact bone, spongy bone inside
  • Ex: Sternum, skull, ribs, shoulder blades
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7
Q

Short bone

Type of Bone

A
  • cube shaped
  • thin external coat of compact bone, spongy bone inside
  • Ex: carpel, tarsal, talus
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8
Q

Long Bone anatomy

A
  1. Ends of long bone are proximal epiphysis and distal epiphysis
  2. Diaphysis
  3. Articular (hyaline)
  4. Epiphyseal plate
  5. Periosteum
  6. Endosteum
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9
Q

Diaphysis

Lone Bone Anatomy

A

compact bone has yellow marrow cavity inside

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10
Q

Epiphysis

Long Bone Anatomy

A
  • external compact bone
  • internal spongy bone
  • has red marrow
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11
Q

Articular (hyaline) cartilage

Long Bone Anatomy

A

cushions bone ends

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12
Q

Epiphyseal plate

Long Bone Anatomy

A

for interstitial growth

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13
Q

Periosteum

Long Bone Anatomy

A
  • covers the external surfaces
  • has osteogenic cells for appositional growth
  • attached to underlying bone with Sharpies fibers (collagen)
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14
Q

Endosteum

Long Bone Anatomy

A
  • covers the inner surfaces
  • composed of osteogenic cells
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15
Q

Flat Bone Anatomy

A
  1. Suture
  2. Outer Compact Bone
  3. Spongy Bone (diploe)
  4. Trabeculae
  5. Inner compact bone
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16
Q

Osteogenic

Cell Type

A

bone stem cells

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17
Q

Osteoblasts

Cell type

A

synthesize (make) new bone matrix

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18
Q

Osteocytes

Cell Type

A
  • mature cells that maintain the matrix around them
  • live in lacunae inside bone
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19
Q

Osteoclasts

Cell Type

A
  • formed from fusion of many WBCs
  • found in endosteum
  • secrete enzymes that break down bone matrix from ruffled border side
20
Q

Haversian systems

Compact Bone Anatomy

A

Made of osteons

21
Q

Osteons

Compact Bone Anatomy

A

layers of concentric lamellae around a Haversian (central) canal

22
Q

Lamellae

Compact Bone Anatomy

A

composed of parallel bundles of collagen fibers in calcified matrix

23
Q

Lacunae

Compact Bone Anatomy

A
  • with osteocytes living in them
  • found between adjacent lamellae
24
Q

Volkman (perforating) canals

Compact Bone Anatomy

A

connects the vessels in the periosteum and central canals

25
Q

Osteocytes

Compact Bone Anatomy

A
  • live in lacunae
  • send cellular projections into the canaliculi
  • The projection from one osteocyte meets the next osteocyte with gap junction between them
    – Allows nutrients, wastes, chemical signals, etc to get to osteocytes
26
Q

Canaliculi

Compact Bone Anatomy

A

small canals that connect the lacunae

27
Q

Spongy Bone Anatomy

A
  • No osteons
  • Incomplete lamellae form a scaffolding of trabeculae
  • Trabeculae contain lacunae and canaliculi with osteocytes
28
Q

Osteogenesis

A
  • (ossification) = formation of bone
  • Begins in the early weeks (5 – 6) of embryo development
    Two processes:
    1. Intramembraneous ossification – flat bones
    2. Endochondral ossification – all other bones esp. long bones
29
Q

Interstitial Growth of the Long Bones

A

Resting Zone: Nearest epiphysis
1. Proliferation zone: carilage cells undergo mitosis
2. Hypertrophic zone: older cartilage cells enlarge
3. Calcification zone: matrix becomes calcified; cartilage cells die; matrix begins deteriorating
4. Ossification zone: New bone formation is occuring

30
Q

Closure of the Epiphyseal Plate

A
  • Late teens (female ~ 18, males ~ 21)
  • cells in proliferating zone divide less frequently, but replacement at the diaphysis side remains constant
  • Plate closes
31
Q

Appositional Growth

A
  • As bone lengthens, adjustments are made to the width to maintain the proper shape
  • Osteoblasts add matrix to the external surface that develop into new osteons
  • Osteoclasts widen the internal area
32
Q

Bone Remodeling

A
  • Ongoing project to replace bone
  • Every week we recycle 5 to 7% of our bone mass. Spongy bone replaced every three to four years, compact bone every ten years or so.
  • Purpose: renews bone tissue before deterioration sets in AND redistributes bone matrix along lines of mechanical stress.
  • Osteoclasts tunnel through/remove old bone (reabsorption) and osteoblasts follow making new bone (bone deposition)
  • Requires minerals (Ca2+ , PO4-, Mg2+) and vitamins (C, B12, A) and hormones (growth hormone - GH, thyroid hormone (TH), sex hormones, parathyroid hormone (PTH), and calcitonin)
33
Q

Blood Calcium
Homeostasis

A
  • HIGH blood Ca –> Calcitonin released –> stimulates calcium salt deposit in bone
  • LOW blood Ca –> PTH released
34
Q

Thickening of Bones

A

Controlled by bone cells:
- Osteoblasts (under periosteum)
– Secrete bone matrix on outer surface –> Bone becomes thicker
- Osteoclasts (in endosteum)
– Break down bone –> Medullary cavity widens
– Shaft diameter increases

35
Q

Bone Fractures

A
  1. Nondisplaced
  2. Displaced
  3. Complete
  4. Incomplete
  5. Linear
  6. Transverse
  7. Compound
  8. Simple
36
Q

Comminuted

Bone Fracture

A

Bone fragments into three or more pieces
- due to age

37
Q

Compression

Bone Fracture

A
  • Bone is crushed
  • Ex: crushed vertebra
  • osteoporotic
38
Q

Spiral

Bone Fracture

A
  • ragged break occurs when excessive twisting frces are applied to a bone
  • due to sports injury
39
Q

Epiphyseal

Bone Fracture

A
  • epiphysis seperates from the diaphysis along the epiphyseal plate
40
Q

Depressed

Bone Fracture

A

Broken bone portion is pressed inward
- typically a skull fracture

41
Q

Greenstick

Bone Fracture

A

Bone break is incomplete
- occurs in kids

42
Q

Healing of Bone Fracture

A
  1. A Hematoma forms
  2. Fibrocartilaginous callus forms
  3. Bony callus forms
  4. Bone remodeling occurs
43
Q

Osteoporosis

A
  • Bone reabsorption occurs faster than bone deposit = net bone loss
  • Chemical composition remains the same
  • Bones become light, porous and fragile particularly femur and vertebra
44
Q

Osteoporosis: Risk Factors

A
  • Genetics
  • Postmenopausal or ovary removal (estrogen inhibits PTH activity)
  • Lack of exercise to stress bones
  • Thin/small body frame
  • Poor nutrition: especially Vitamin D and calcium
  • Smoking: reduces estrogen levels
45
Q

Sesamoid bones

A
  • (sesame seed shaped short bone) forms in tendons
  • alter direction of pull of a tendon