Ch. 6 Skeletal System Flashcards
1
Q
Describe the matrix of bone
A
- 2% bone cells (osteocytes) within lacunae
- 2/3rds calcium phosphate
- 1/3 collagen fibers
2
Q
lacunae
A
the space occupied by either osteocytes or chondrocytes
3
Q
canaliculi
A
- narrow pasageways through matrix for the exchange of nutrients, waste, and gases
- contain cytoplasmic extensions of osteocytes
4
Q
what type of bone does not have a periosteum?
A
joints/articulated
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
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
7
Q
What are the 4 cells of bone?
A
- osteocytes
- osteoblasts
- osteoprogenitor cells
- osteoclasts
8
Q
osteocytes
A
- Mature bone cells
- only in lacunae, between lamellae
- extend through canaliculi and link by gap junctions
- Do not divide
Functions:
- To maintain protein and mineral content of matrix
- To help repair damaged bone
9
Q
lamellae
A
layers of matrix that separate osteocytes
10
Q
ossification; osteogenesis
A
the production of new bone matrix by osteoblasts
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
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
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
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
15
Q
osteolysis (resorption)
A
acids and proteolytic enzymes secreted by osteoclasts dissolve the matrix and release stored minerals
16
Q
What are the five functions of the skeletal system?
A
- Support
- Storage of minerals and lipids
- Blood cell production
- Protection
- Leverage
17
Q
What is stored in bone?
A
- calcium
- phosphate ions
- yellow bone marrow (lipid energy reserves)
18
Q
What are the 6 categories of bone shape?
A
- Sutural bones (Wormian bones)
- Irregular bones
- Short bones
- Flat bones
- Long bones
- Sesamoid bones
19
Q
Sutural bones
(Wormian bones)
A
- Small
- Flat
- Irregular shape
Between the flat bones of the skull. Jigsaw puzzle.
20
Q
Irregular bones
A
- Complex shape
- Short, flat, notched or ridged
Location: Spinal vertebrae, bones of pelvis, some skull bones
21
Q
How are bones classified?
A
- Shape
- Internal tissue organization
- Bone markings
22
Q
Short bones
A
small and boxy
Ex: carpal and tarsal bones
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
24
Q
Long bones
A
Long and slender
25
Sesamoid bones
small, flat and shaped like sesame seeds
develop inside tendons
commonly located near joints; vary between individuals
Ex: Patella
26
* Small
* Flat
* Irregular shape
Between the flat bones of the skull. Jigsaw puzzle.
Sutural bones
| (Wormian bones)
27
* Complex shape
* Short, flat, notched or ridged
**Location**: Spinal vertebrae, bones of pelvis, some skull bones
Irregular bones
28
small and boxy
Ex: carpal and tarsal bones
Short bones
29
thin, parallel surfaces. Provide protection for underlying soft tissuse and extensive surface area for muscle attachment
Ex: roof of skull
sternum
ribs
scapulae
Flat bones
30
Long and slender
Long bones
31
small, flat and shaped like sesame seeds
develop inside tendons
commonly located near joints; vary between individuals
Ex: Patella
Sesamoid bones
32
diaphysis
extended tubular shaft of a long bone
33
epiphysis
expanded area of the long bone
34
metaphysis
the narrow zone that connects the diaphysis and epiphysis
35
dense bone
the layer of compact bone that makes up the wall of the diaphysis
36
compact bone
* forms a sturdy protective layer that surrounds the medullary cavity
* All osteons are aligned in the same direction
37
medullary cavity
marrow cavity; the central space in long bones
38
cancellous; trabecular bone
spongy bone that makes up the epiphyses
39
spongy bone
* 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
cortex; cortical bone
the thin covering of compact bone over spongy bone
41
Diploë
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
osteon, Haversian system
the basic unit of **mature compact bone**
Key Features:
* *concentric lamellae*
* central (Haversian) canal
* perforating (Volkmann's) canals
43
Haversian canal
* central canal
* contains one or more blood vessels
* generally parallel to surface of bone
44
Volkmann's canals
* perforating canals
* perpindicular to surface
* supply blood to deeper osteons and medullary cavity
45
concentric lamellae
layers of matrix that extend outward from the central canal
46
interstitial lamellae
* layers of matrix that fill spaces between osteons in compact bone
* remnants of recycled osteons
47
circumferential lamellae
* found at the outer and inner surfaces of bone
* covered by periosteum (outer) or endosteum (inner)
48
layers of matrix that extend outward from the central canal
concentric lamellae
49
* layers of matrix that fill spaces between osteons in compact bone
* remnants of recycled osteons
interstitial lamellae
50
* found at the outer and inner surfaces of bone
* covered by periosteum (outer) or endosteum (inner)
circumferential lamellae
51
* central canal
* contains one or more blood vessels
* generally parallel to surface of bone
Haversian canal
52
* perforating canals
* perpindicular to surface
* supply blood to deeper osteons and medullary cavity
Volkmann's canals
53
trabeculae
fiber bundles composed of matrix that create the supporting meshwork of spongy bone
54
fiber bundles composed of matrix that create the supporting meshwork of spongy bone
trabeculae
55
red bone marrow
fills the space between trabeculae
* has blood vessels
* forms red blood cells
* supplies nutrients to osteocytes through canaliculi
56
yellow bone marrow
fills space between trabeculae in some spongy bone; stores fat
57
**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
1. Hip-joint
2. Knee joint
3. Tension
4. Compression
58
Functions of periosteum
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
Sharpey's fibers
* Perforating fibers
* collagen fibers incorporated into bone tissue from tendons and ligaments, or superficial pereosteum
60
endosteum
* 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
osteoclastic crypts
shallow depressions that have eroded into the matrix exposed to the endosteum
