Chapter 6 Flashcards
(78 cards)
1
Q
what is the skeletal system
A
Includes the bones, joints, and other
supporting tissues
2
Q
how many bones do adults typically have
A
206
3
Q
each bone includes
A
▪ Bone (Osseous) Tissue
▪ Dense regular collagenous tissue
▪ Dense irregular connective tissue
▪ A tissue called Bone Marrow
4
Q
functions of the skeletal system
A
- protection
- mineral storage
- acid/base homeostasis
- blood cell formation
- fat storage
- movement
- support
5
Q
skeletal system - protection
A
Bones such as the skull, sternum, and ribs protect
underlying organs
6
Q
skeletal system - blood cell formation
A
Red Bone Marrow in bones is the site of hematopoiesis, or formation of blood cells
7
Q
skeletal system - mineral storage and acid/base homeostasis
A
Bone stores minerals including
calcium, phosphorus, and magnesium salts; These minerals are
electrolytes, acids, and bases in the blood, and are critical for
electrolyte and acid-base maintenance
8
Q
skeletal system - fat storage
A
Yellow Bone Marrow in bones contains adipocytes with stored triglycerides
9
Q
skeletal system - movement
A
Bones are the sites of attachment for most skeletal
muscles; When muscles contract, they pull the bones which generates
movement around a joint
10
Q
skeletal system - support
A
The skeleton supports the weight of the body and provides its structural framework
11
Q
bone classification by shape
A
- long bones
- short bones
- flat bones
- irregular bones
- sesamoid bones
12
Q
short bones
A
- About as long as wide or roughly cube-shaped; Examples include the wrist and ankle bones
13
Q
long bones
A
- Longer than wide; Examples include bones of the limbs; Some long bones are very small
14
Q
flat bones
A
- Thin and broad; Examples include most of the skull bones and bones of the pelvis
15
Q
irregular bones
A
- Irregular shapes; Examples include the vertebrae
16
Q
sesamoid bones
A
- Small, flat, oval-shaped bones located within tendons; An example is the kneecap
17
Q
parts of a long bone
A
- periosteum
- perforating fibers
- diaphysis
- epiphyses
- compact bone
- spongy (cancellous) bone
- epiphyseal lines
18
Q
periosteum
A
Outer dense irregular connective
tissue membrane with blood vessels and nerves
19
Q
perforating fibers
A
Collagen anchors that
penetrate into bone matrix to attach the periosteum
20
Q
diaphysis
A
Shaft of the bone with
a medullary marrow cavity lined by the Endosteum
(A membrane lining the inner surface of the bony
wall) and filled with marrow
21
Q
epiphyses
A
Ends of a long bone (filled with Red
Marrow) covered with Articular Cartilage, which is
composed of hyaline cartilage
22
Q
spongy bone aka
A
cancellous bone
23
Q
compact bone
A
Hard, dense outer bone that
resists linear compression and twisting forces
24
Q
spongy (cancellous) bone
A
Inner, honeycomb-
like bone framework that resists forces in many
directions and provides a place for bone marrow to
reside
25
epiphyseal lines
Remnants of an Epiphyseal
(Growth) Plate, which is a line of hyaline cartilage
actively growing in children and adolescents
26
in flat bones, spongy bone is called
diploe
27
what are sinuses
air filled spaces in some bones of the skull to make them lighter
28
nutrient arteries enter bones through
hole in diaphysis called nutrient foramen
29
yellow bone marrow
Consists mostly of blood vessels and adipocytes. (Can make catilage, bone, or during life threatening emergencies can turn to red bone marrow to produce blood cells)
29
infants and young children mostly have what kind of bone marrow
red bone marrow
29
red bone marrow
Red Bone Marrow—Network of reticular fibers supporting
islands of hematopoietic cells
(where red blood cells , white blood cells, and platelets form)
30
adults have mostly what kind of bone marrow
yellow bone marrow
31
what is the ecm of bones called
bone matrix
32
lamellae aka
contentric lamellae
32
histology - compact bone
- Hard, dense, outer shell that is able to resist a great
amount of stress that would typically strain or deform an object
– Units are called osteons or Haversion Systems
32
organic matrix (osteoid)
– Consists of protein fibers (mostly collagen),
proteoglycans, glycosaminoglycans, glycoproteins, and
bone-specific proteins such as Osteocalcin
– Collagen helps bone resist torsion (twisting) and
tensile (pulling or stretching) forces that would cause
breaks in bones, and aligns with hydroxyapatite
crystals to enhance bone hardness
33
the ecm of bones
* Inorganic Matrix—About 65% of bones total weight
* Consists mostly of calcium salts and phosphorus as part of
a large mineral called hydroxyapatite crystals
10 4 6 2Ca PO O[ ) ( H( ) ] which gives bone its hardness and
ability to resist compression and bending
* Bicarbonate 3(HCO ,) potassium, magnesium, and sodium
salts are also in the inorganic matrix
* Organic Matrix (Osteiod)—About 35% of bones total
weight
33
organic matrix aka
osteoid
34
histology - trabeculae
Covered with endosteum; Contain concentric lamellae, houses osteocytes; Access blood supply from blood vessels in bone marrow
34
histology - spongy bone
—Resists forces from many directions and forms a protective framework for the bone marrow although not weight bearing
– Organized into branching “ribs” of bone called Trabeculae
34
osteon structure
- lamellae (concentric lamellae)
- central (haversian) canal
- lacunae
34
what are lamellae
Rings of very thin
layers of bone; Osteons contain 4 to 20 lamellae;
Collagen fibers of adjacent lamellae run in opposite
directions which resists twisting and bending forces
35
what is the central (haversian) canal
Contains blood vessels
and nerves; Lined by endosteum
36
what are lacunae
Small cavities between lamellae filled with E
C F; About 20,000–30,000 osteocytes and lacunae are
found in each cubic millimeter of bone
37
figure 6.9
structure of compact bone
37
what is longitudinal growth
lengthening of bones when chondrocytes divide at the epiphyseal plate
38
How many zones of cells does the epiphyseal plate have
5
38
what are the zones of cells of the epiphyseal plate
- zone of reserve cartilage
- zone of proliferation
- zone of hypertrophy and maturation
- zone of calcification
- zone of ossification
38
what is in the zone of reserve cartilage
- in the epiphyseal plate
- cells are not directly involved in bone growth
- cells can divide if needed
38
what is in the zone of proliferation
- in the epiphyseal plate
- chondrocytes are
39
what is in the zone of hypertrophy and maturation
- in the epiphyseal plate
- contains
39
what is in the zone of calcification
- in the epiphyseal plate
- contains
- matrix becomes calcified
- far from blood supply
40
what is in the zone of ossification
- in the epiphyseal plate
- contains calcified chondrocytes
41
what are the steps of longitudinal growth
1. chondrocytes divide in the zone of proliferation
2. chondrocytes that reach the next zone enlarge and mature - lacunae surrounding the chondrocytes are larger here
3. chondrocytes die and their matrix calcifies
4. calcified cartilage is replaced with bone - in the zone of ossifiction, osteoblasts invade the calcified cartilage and lay down bone. Osteoclasts reabsorb the calcified cartilage/bone which is replaced by bone
42
longitudinal growth ontinues at the epiphyseal plate as long as _______ mitosis is happening in the zone in proliferation
mitosis
43
when does the zone of proliferation completely ossify after bone growth in length
between 13 to 21 years
43
at what age does the rate of mitosis slow for bone growth in length
12-15 years
44
the remenant left behind when the zone of proliferation completely ossifies after bone growth in length
45
what is appositional growth
growth of all bones in width - may continue after bone growth in length bone growth in length ceases
46
explain appositional growth
- growth of all bones in width
- may continue after bone growth in length ceases
- oseoblasts between the periosteum and the bone surface lay down new bone
- begins with the formation of new circumferential lamellae; as new lamellae are added, the deeper circumferential lamellae are removed or incorporated into osteons
- primarily thickens the compact bone of the diaphysis; osteoclasts in the medullary cavity digest the inner circumferential lamellae so as bones increase in width, their medullary cavities enlarge as well
47
why does bone remodeling occur
- maintenance of calcium ion homeostasis
- bone repair
- replacement of primary bone with secondary bone
- replacement of older, brittle bone, with newer bone
- bone adaptation to tension and stresses
47
what is bone remodeling
the continual process of bone formation, by bone deposition, and bone loss, by bone resorption
48
in healthy adult bone, bone formation and bone loss occur simultaneously by ... respectively
osteoblasts and osteoclasts
49
how does bone remodeling happen in response to tension and stress
the heavier the load a bone carries, the more bone tissue is deposited in that bone
tension - stretching force, stimulates bone resorption
pressure - application of a continuous downward force; stimulates bone deposition
50
what is bone deposition
- osteocytes in newly deposited bone
- osteoblasts depositing bone
51
how does calcium ion intake affect bone remodeling
required for bone deposition
51
what is bone resorption
- osteocytes breaking down bone
51
how do hormones affect bone remodelling
testosterone strongly promotes bone deposition, while estrogen depresses osteoclast activity
51
how does age affect bone remodeling
hormones decline with advancing age, such as growth hromone, which causes a reduction in protein synthesis, and estrogen, which reduces the protective effects of the hormone on bone remodeling
52
which nutrients affect bone growth
- calcium ion
- vitamin d
- vitamin k
53
how does vitamin d intake affect bone remodeling
promotes calcium ion absorption in the intestine and prevents calcium loss in the urine; inadeqaute amounts in children causes rickets, which results in bone deformities, fractures, and muscle weakness
54
how does vitamin k intake affect bone remodeling
required for osteocalcin to bind to calcium ions; promotes proliferation of osteoblasts, increases their lifespan, and causes them to deposit more matrix; inhibits osteoclast division and activity
55
what are the steps of fracture healing
1. a hematoma fills the gap between the bone fragments
2. fibroblasts and chondroblasts infiltrate the hematoma, and a soft callus forms
3. osteoblasts build a bone callus
4. the bone callus is remodeled and primary bone is replaced with secondary bone
56
what are the classes of bone fractures
- simple (closed) fractures
- compound (open) frcatures
57
what are compund fractures
damage around the fracture
57
what are simple fractures
skin and surrounding tissue remain intact
58
what is the treatment for a fracture
stabilization of the fracture, followed by immobilization for about 6 weeks
58
what is a closed reduction
a treatment for bone fractures
bone end are brought into contact
