Musco-skeletal Flashcards
1
Q
Usage of word ‘bone’
A
As the organ, or the tissue
2
Q
Functions of bone
A
Protection Support Movement Calcium/phosphorus reserve Haemopoeisis (red) Fat storage (yellow) (or please stop making children have fatalities)
3
Q
Axial bone
A
Ribs, vertebrae, skull
4
Q
Appendicular bone
A
All movement bones, non-axial
5
Q
Red bones are
A
Axial
6
Q
Yellow bones are
A
Appendicular
7
Q
Longitudinal sections of a long bone
A
Epiphysis Metaphysis Diaphysis Metaphysis Epiphysis
8
Q
Outer layer of bone
A
Periosteum (fibrocellular)
9
Q
Inner layer of bone
A
Endosteum (fibrocellular)
10
Q
Bone marrow located
A
Diaphysis
11
Q
Sharpey’s fibres
A
Fibres joining periosteum to endosteum
12
Q
ECM of bone
A
Fibre -> Collagen (I,V) for stretch and pull
Ground substance -> hydroxyapatite for squeezing and compression
13
Q
Cells of bone
A
Osteogenic stem cell Osteoblast Osteocyte Osteoclast For torsion forces (twisting)
14
Q
Articular cartilage
A
Outside layer of epiphysis, where periosteum is not
15
Q
Layers of epiphysis
A
Articular cartilage, compact bone, spongy bone
16
Q
Medullary cavity
A
Spaces in-between bone, or trabeculae
17
Q
Spongy bone design
A
Trabeculated, covered in endosteum, for support of perpendicular forces
18
Q
Mesenchyme stem cells give rise to ____ what is this cells function/location?
A
Osteogenic cells, found in peri/endosteum and central canal of compact bone, lays dormant mainly, divides into other bone cells (not osteoclast)
19
Q
Osteoblasts location function and precursor
A
Location - Where bone is forming, peri/endosteum
Function - To form new bone by making osteoid
Precursor - Osteogenic stem cells
20
Q
Osteocytes function, location and precursor
A
Location - Lacunae, cell processes through canaliculi
Function - Maintenance of bone, communication to other osteocytes. Cellular processes extend to other osteocytes
Precursor - Osteoblast gets trapped in lacunae and becomes osteocyte
21
Q
What is osteoid made of
A
Collagen
22
Q
Precursor of osteoblast
A
Blood monocyte progenitor cell fusion
23
Q
How are osteoblasts formed
A
Monocyte progenitor cells fuse to form a syncytium
24
Q
Function/shape of osteoclast
A
Large, multinucleated cell, convoluted.
Secretes acid and acid activated enzymes to break down hydroxyapatite and proteins
25
What happens after osteoblasts break down bone?
Endocytosis/exocytosis
26
Space between bone tissue and osteoclast
Howship's lacunae
27
A section of bone has only flat cells. What is this cell type, and what is the state of this section of tissue?
Osteogenic cells, resting
28
Difference in diameter of adults bone from childrens
Adult has wider diameter, but just larger lumen. Width of tissue wall similar
29
Why can't bone grow through interstitial growth
Too dense
30
What is the growth of bone called?
Appositional growth
31
Outline bone growth
On periosteum, appositional growth occurs
| At endosteum, reabsorption occurs.
32
Outline appositional growth
Signal to ostegenic cell
Cells multiply to create osteoblasts
Osteoblasts reside between osteogenic cells and bone tissue
Osteblasts lay osteiod, some become trapped and turn into ostecytes
Osteiod is calcified
Osteoblasts die, or revert to osteogenic cells
33
When do canaliculi grow
During bone formation
34
Ricket's disease
Lack of calcification from malnutrition
35
Outline bone reabsorption
Monocyte progenitor cells combine to create a syncytium (osteoclast)
Osteoclast at endosteum, moves between bone tissue and osteogenic cells
Secrets acid and enzymes to break bone down
Broken down bone is endocytosed and then exocytosed
Osteoclasts undergo apoptosis
36
Why do bones have different strengths at different ages?
Ratios between rates of appositional growth and bone reabsorption change
37
How do long bones lengthen?
At epiphysis, articulate hyaline cartilage grows outward due to chondrocytes, boarder where articulate cartilage meets epiphysis is where cartilage dies and bone is replaced instead
38
Epiphyseal line
Where articulate plate origninally sat
39
Types of bone
Woven bone and lamellar bone
40
Outline properties and instances of woven bone
Found in infants and following tissue trauma.
Wavy collagen fibers
Not a dense arrangement
Cannot withhold tension
Is like this as bones were under no tension in the womb
41
Outline properties and instances of lamellar bone
```
In grown adults/mature bone
Very strong
Collagen layers
multidirectional layering
means tension can be withheld from multiple directions
```
42
Outline spongy bone properties/where it can be found
```
Found at epiphysis
Trabeculated
Trabeculae covered in endosteum
Lots of osteoclasts
Blood vessels are found in medullary cavity
Grows from outwards inwards
layered bone
```
43
How come osteocytes in trabeculae of spongy bone get nutrients?
Only can be a certain thickness
44
Outline compact bone properties/where it can be found
Found in diaphysis
Cylindrical layers called osteons
Volkmann's canal/haverstian canal runs through oseons
Nutrients goes from inside to outside
45
Types of lamellar bone
Circumferential
Interstitial
Concentric
46
How are primary osteons formed
During appositional growth, periosteum grows faster than bone, which creates ridges that become enclosed
After this, The endosteum of the ring forms bone inwards to narrow the tunnel (blood vessels reside here)
47
What is the type of lamellae found in osteons?
Concentric
48
Issue with excess circumferential lamellae?
Increased distance, difficulty designing blood supply
49
How are secondary osteons formed
Monocyte progenitor cells from blood vessels leave blood vessel, forming syncytiums (osteoclasts)
Osteoclasts form a cutting cone, or drill that moves through the old bone clearing it away 1mm/20days
osteogenic cells move in behind, forming endosteum
Endosteum lays down new bone from outside inwards
blood vessels following the osteoclasts
50
What is the cement line
Where new bone has began to form against old bone
51
Maximum width of bone for blood/nutrient perfusion
0.4mm
52
In X-ray, how is new bone identified
Darker due to less calcification, probes leave larger inprint as bone is softer
53
Define an arthrosis
Any point where 2 or more bones meet
54
Functions of arthrosis
Movement
Force transmission
Growth
55
What is the fontanelle
Soft region of diarthrosis on babies head
56
Typer of arthrosis
Synarthrosis
Amphiarthrosis
Diarthrosis
57
Function of synarthrosis
high stability, low movement, in axial skeleton, absorb forces
58
Function of amphiarthrosis
Some movement, not entirely free movement, some stability
59
Function of diarthrosis
Freely mobile, low stability
60
Ankylosis
fusion of arthrosis
61
What tissue type are simple synovial joints
Diarthrosis joints
62
Features of synovial joints
Articular cartilage
Articular Capsule
Joint cavity
Synovial fluid
63
What is articular cartilage
Specialized hyaline cartilage
64
Function of articular cartilage
Protection of the ends of bones, support, shock absorption, friction-less surface, heavy loads etc
65
What is articular cartilage made of
```
Cells (5%)
- Chondrocytes
ECM (95%)
- Ground substance
- Water, soluble ions, GAGs and PGs
- Fibres
- Collagen type ll
```
66
Function of glycosaminoglycans and proteoglycans in articular cartilage
Water compartment/swelling of tissue
67
Forces which cartilage resists
Expansion (swelling force), compression, shear
68
Regions/zones of articular cartilage
1. Surface zone (5-10%)
- Low PG, horizontal fibers for shear force
2. Middle zone (40-45%)
- More collagen & PG
- Les compact arrangement
- Criss-cross or 45 degree fibers
3. Deep zone
- Nests of cells
- Most PG
- Vertical fibers
4. Tidal mark
- Calcification
5. Calcified zone
6. Cement line
- Collagen binds to this
- Cells here and from tidal mark down secrete hydroxyapatite
69
Vasculature of cartilage
No vessels, nerves or lymphatics
70
how does cartilage prevent expansion force
Fibers from surface zone steepen and anchor to lamellear bone bellow, holding tension
71
What does GAG stand for, and how is it made?
Glycosaminoglycan
Made out of repeating units of disaccharides
Disaccharides are two monosaccharides joined together
72
Examples of GAGs, and their charges
Chrondriotin (-), keratin sulphate (-)
73
Outline hyaluronic acid
A long GAG, very very long, that has proteoglycans on it and is therefore a proteoglycan complex
74
Proteoglycans??
A protein core with GAGs bound to it
75
Where is hyaluronic acid commonly found, and why
In the middle to deep zone or articular cartilage, attached to collagen fibers.
The negative charges of the GAGs on the core proteins draw positive ions (Na+, K+, Ca2+) into the cartilage, and this draws water inwards also due to a change in osmotic gradient
76
Influx of water in articular cartiage stops when
Unloaded equilibrium is reached. This is when swelling force of water equals tension of collagen
77
What happens to articular cartilage under compression?
Water is squeezed out
78
What is the fluid component of articular cartilage?
Water and ions
79
How do chondrocytes in articular cartilage get nutrients/get rid of waste?
By dissolving water and CO2 in the water
80
What is an osteophyte
Bone growing in a synovial joint where it shouldn't be
81
Layers of articular capsule
Fiberous (outer) and synovial membrane (inner)
82
Outline what the fiberous layer of the articular capsule is made of
Dense (irregular or regular connective tissue)
Fibroblasts, nerves, few blood vessels etc
Specifically pain and proprioceptive nerves
83
What is the purpose of irregular dense connective tissue in the articular capsule?
To resist forces from varying directions
84
Where does the fiberous layer of the articular capsule end
Meets periosteum
85
Outline the synovial membrane
Has an intima and subintima layer
Loose variable connective tissue
Villi to increase surface area
In subintima layer, there are few fibroblasts, some macrophages, adipocytes, blood vessels, etc
In intima layer, there are synoviocytes, that secrete hyaluronic acid and lubricating proteins
86
Where are synovial membranes found
Lines the entire joint cavity in absence of articular cartilage
87
Where does synovial fluid come from?
It is a blood plasma filtrate from the vessels in the subintima layer of the articular capsule
88
Outline the features of the joint cavity
It is a potential space rather than a cavity
Cartilage on cartilage contact is only about 50%
Very little (max 2ml) synovial fluid
89
How do muscles create movement
Conversion of ATP into mechanical movement
90
Functions of muscles
```
Movement
Stability
Communication
Control of body openings and passages
Heat production (over 80% of bodies heat)
```
91
What is the region where a tendon joins to bone called
Osteotendinous junction
92
MTJ
Myotendinous junction
93
Insertion of muscle
The attachment that moves the most, typically appendicular
94
Origin of muscle
The attachment that moves the least, typically axial
95
average width of a myocyte
10/100 micro meters
96
Zones of a myofibril
Z bands, I bands, A bands
97
Dark bands vs light bands
Dark bands are A, Light bands are I
98
What is a fasicle
A group of myocytes
99
What is a fascile surrounded by
Perimysium
100
What is a muscle immediately surrounded by
Epimysium
101
What are myocytes surrounded by (immediately then after)
Basement membrane then endomysium
102
What are myofibrils surrounded by
Sarcoplasm
103
What are muscles coated in?
Deep fascia
104
Where are most of the blood vessels and nerves found in a muscle
In the endomysium within a fasicle
105
From outside to inside, what are the layers of the muscle
Skin -> Subcutaneous/superficial fascia -> Deep fascia -> Epimysium -> Muscle -> perimysium -> fasicle -> endomysium -> basement membrane -> myocyte
106
With a microscope, what is the smallest section of a muscle you will be able to see?
Myofibrils
107
Intermuscular septa
Barrier inbetween muscles
108
Where deep fascia meets bone is called
Periosteum
109
How do muscles grow
Hypertrophy
110
Outline hypertrophy vs hyperplasia
Hypertrophy is the muscle cells getting bigger, with more organelles such as myofibrils forming
Hyperplasia is the growth of numbers of cells
111
Hypoplasia
Death of cells
112
Atrophy
Muscles getting smaller in inter-cellular contents
113
Outline anabolic steriods
Increases the protein synthesis processes in the body, resembles puberty
114
Outline function of satellite cells
They are myoblasts that sit in the outside of the cell and can multiply, this is why myocytes are a syncytium
115
Functions of the epi/peri/endomysium
1. organisation and scaffolding
2. Blood vessels and nerves
3. Protect/prevent overstretching
4. Distribute force of muscle
116
How is contraction and distribution of force in muscles even?
Through desmin proteins that link adjacent Z discs together, and through protein complexes that link the outer most myofibril's Z line/disc to the sarcolemma, basement membrane and endomysium
