The Musculoskeletal System Flashcards
1
Q
Main functions of the Musculoskeletal System?
A
- Movement
- Support and protection
- Storage and release of minerals
- Medullary cavity
- Endocrine function
2
Q
Musculoskeletal System movement is a system of…
A
…pulleys and levers
3
Q
5 main types of bone:
A
- Long
- Short
- Flat
- Irregular
- Sesamoid
4
Q
The shape of bones determine their…
A
… function
5
Q
Long bones have a greater length than…
A
… width.
6
Q
Long bones consist of a…
A
…shaft (diaphysis), a variable number of
extremities or epiphyses (ends) and are slightly curve
7
Q
Examples of long bones are…
A
…femur, tibia, fibula, ulna, radius, phalanges
8
Q
Short bones are nearly equal in…
A
…length and width
9
Q
Short bones are somewhat…
A
…cube shaped
10
Q
Short bones consist of…
A
…spongy bone tissue
11
Q
Short bones consist of spongy bone tissue except at the…
A
…surface.
12
Q
Short bones consist of spongy bone tissue except at the surface, which
has a layer of …
A
…compact bone tissue
13
Q
Examples of short bones are…
A
…most carpal (wrist) and tarsal (ankle) bones
14
Q
Flat bones are generally…
A
…thin; afford considerable protection
15
Q
Flat bones are composed of…
A
…two nearly parallel plates of compact bone tissue enclosing a layer of spongy bone tissue
16
Q
Examples of flat bones:
A
cranial bones, sternum, ribs, scapulae
17
Q
Amount of spongy and compact
bone present of irregularly-shaped bones ….
A
…varies
18
Q
Examples of irregularly-shaped bones:
A
vertebrae; ilium, ischium,
pubis, sacrum (pelvic girdle)
19
Q
Sesamoid are shaped like a…
A
…sesame seed
20
Q
Sesamoid bones develop in certain tendons, where there is considerable…
A
…friction, tension and physical stress
21
Q
Sesamoid protect tendons from…
A
…excessive wear and tear.
22
Q
Sesamoid bones often change the …
A
…direction of pull of a tendon
23
Q
Sesamoid bones often change the direction of pull of a tendon which improves…
A
…the mechanical advantage at a joint
24
Q
Examples of sesamoid bones:
A
patellae (kneecaps), palms, soles of feet
25
Long bones have thickened heads called...
...epiphyses
26
Long bones have a central shaft called a...
...diaphysis
27
Periosteum is a membrane that...
... lines the outer surface of all bones
28
Periosteum is a type of...
Specialised connective tissue
29
Tendons and ligaments attach to the ...
... periosteum
30
Periosteum are essential for...
...bone growth and repair – vascularisation.
31
Periosteum have nerve endings so are highly sensitive to...
...manipulation
32
The compact bone is a ...
....protective outer shell around every bone in the body.
33
Compact bone makes up...
...80% of the skeletal mass
34
Compact bone has high resistance to...
...bending torsion, which provides strength where bending would be undesirable.
35
Compact bone is replaced, but it has a...
...slow rate of turnover.
36
What are osteons?
series of adjacent and overlapping calcium phosphate formations --> functional unit of compact bone.
37
Central vascular canals of osteons are...
...haversian canals (canals of havers)
38
Located within the haversian canals are...
‒ Capillaries
‒ Nerves
‒ Lymph vessels
39
Osteocytes make...
...canaliculi
40
Each Haversian canal is surrounded by:
‒ concentric layers of bone matrix (lamellae)
‒ concentric rings of bone-forming cells (osteocytes)
41
Spongy bone is also called...
...Trabecular bone
42
What percentage of skeletal mass does spongy (trabecular) bone make up?
20% of the skeletal mass, 80% of bone surface
43
Spongy bone is less dense but more...
...elastic
44
Spongy (Trabecular) Bone has a higher...
...turnover rate.
45
Where is Spongy (Trabecular) Bone found?
Found at the ends and growing regions of long bones and throughout the interior of short bones.
46
Spongy (Trabecular) Bone acts as a ...
Structural mesh that maintains bone shape despite compressive forces.
47
Secondary sexual characteristics in males include:
– Enlargement of the larynx & laryngeal muscle
– Enlargement of the genitalia
–Growth of pubic hair
–Growth of facial hair
–Bone growth (growth spurt, become broader in the shoulders)
- Fusing of epiphyseal plates (hyaline cartilage plate in the metaphysis, found at each end of the long bones)
48
During growth, bone becomes...
...larger, heavier and denser.
49
Bone formation takes place until the bone is at...
...maximum density and strength (Osteogenesis)
50
Once osteogenesis occurs...
... biological maturity is reached
51
Bones develop from a...
...cartilage template or 'model' that resembles the bone that will form.
52
The cartilage is then slowly
replaced with...
...bone (frontanelle)
53
As adults, bone strength is maintained by...
...constant renewal.
54
As adults, bone strength is maintained by constant renewal, during which...
...old bone is removed (resorption) and new bone created (formation).
55
As adults, bone strength is maintained by constant renewal, during which old bone is removed (resorption) and new bone created (formation).
This process is known as...
...Bone Remodelling
56
Bone Remodelling is undertaken and regulated by the actions of...
‒ Osteoblasts (bone formation)
‒ Osteoclasts (bone resorption)
‒ Parathyroid Hormone (PTH) and Calcitonin
57
Functions of osteoblasts?
bone formation
58
Osteoblasts are specialized...
...fibroblasts.
59
What do osteoblasts secrete?
sialoprotein, osteocalcin, osteoid (type I collagen), etc.
60
Function of osteoclasts?
bone resorption.
61
Osteoclasts are specialised...
...macrophages
62
Osteoclasts secrete...
...tartrate resistant acid phosphatase (TRAP), cathepsin K, etc.
63
Eroded cavities filled with...
...new bone.
64
Slide 32
65
Osteoclasts act on the...
... spongy (trabecular) bone surface to erode the mineral matrix and create cavities on the bone surface.
66
Slide 35
67
Slide 36
68
In adulthood formation and reabsorption is in...
... equilibrium
69
In ageing, there is more...
... resorption than formation
70
In the synovial joints, surfaces slide...
...freely over each other with little friction
71
Synovial joints have a greater ...
... range of motion
72
What does the articular capsule contain?
1. Articular cartilage
2. Synovial membrane
3. Synovial fluid
73
What is Arthrocentesis?
Synovial fluid aspiration; carried out in sufferers of:
‒ synovial infections
‒ gout
‒ arthritis
74
What are ligaments?
Short bands of tough fibrous
tissue composed of collagen
75
What do ligaments connect?
Connect bones to other bones
76
Ligaments limit the mobility of...
...joints or prevent movement entirely
77
What are tendons?
Tough, slightly elastic bands of fibrous tissue that connect muscle to bone.
78
What are the three different types of muscle?
- Cardiac
- Skeletal
- Smooth
(Cardiac + Skeletal = Striated muscle)
79
What muscle is known as striated muscle?
Cardiac and Skeletal muscle
80
Cardiac and smooth muscle =
= involuntary
81
Skeletal muscles tend to be...
...under voluntary control
82
Whats skeletal muscle?
main form of muscle and is used for locomotion and other conscious activities.
83
In eutrophic individuals, the mass of skeletal muscle is about...
...50% of the total body weight
84
What is skeletal (striated) muscle?
Bundles of muscle cells surrounded by envelopes of connective tissue
85
Myocytes -> [...] -> [...] -> [...] ->[...]
Myocytes -> Endomysium -> Muscle fascicle -> Perimysium -> Epimysium
86
What are striated muscles?
myocytes attached end-to-end
87
How does muscle contraction work?
myocyte shortens lengthwise
88
What are myocytes filled with?
filled with cylindrical structures called myofibrils
89
What are myofibrils?
- thin filaments: actin, troponin and tropomyosin
- thick filaments: myosin
90
Seen under a microscope, skeletal muscle has a characteristic pattern of...
...light and dark bands
91
Where do the dark bands occur in myofibrils?
Occur where actin and myosin overlap
92
Where do the light bands occur in myofibrils?
Where no overlap occurs
93
What is the purpose of sarcomeres?
Divides the myofibril up into regions.
94
What are sarcomeres?
functional units of striated muscles
95
What are myofibrils composed of?
Myofibrils are composed of repeating sarcomeres.
96
The end of each sarcomere is delineated by...
...Z-lines
97
Within the Z-lines are other lines and bands which are...
1) The M line
2) I bands
3) A bands
4) The H zone
98
What is the M line?
The M line is the middle of the sarcomere
99
What are I bands?
I bands are lighter areas of non-overlap between actin and myosin.
100
What are A bands?
A bands are darker areas where there is overlap between the actin and myosin filaments
101
Whats the H zone?
The H zone is the area of myosin filaments that does not overlap with actin filaments.
102
What do the thick myosin filaments have?
The thick myosin filaments have heads
103
What do the thin actin filaments have?
The thin actin filaments have binding sites (active sites) to which the myosin heads can attach.
104
What does tropomyosin do when the muscle is at rest?
When the muscle is at rest, tropomyosin blocks the binding sites on the actin filaments so the myosin heads
cannot attach.
105
What is muscle contraction stimulated by?
stimulated by action potential from nerves (neuromuscular junction)
106
What does muscle contraction trigger?
Triggers Ca2+ release from the sarcoplasmic reticulum
107
What does freed calcium bind to during muscle contraction?
Calcium binds to the troponin on the actin filaments.
108
Calcium binds to the troponin on the actin filaments.
This changes the position of...
...the tropomyosin
109
Calcium binds to the troponin on the actin filaments.
This changes the position of the tropomyosin and exposes...
... the myosin binding sites, making them accessible to the myosin heads
110
At rest, the myosin binding sites are blocked by...
...troponin/tropomyosin
111
At rest, the myosin binding sites are blocked by troponin/tropomyosin.
However, on calcium release…
...Calcium attaches to troponin/tropomyosin; they roll away. exposing the active site on actin.
112
Myosin heads bind to...
... the binding sites on the actin
filaments, forming a cross bridge
113
The release of ADP and inorganic phosphate (Pi) causes the myosin head to...
...pivot, pulling the actin filaments
inwards (power stroke)
114
The release of ADP and inorganic phosphate (Pi) causes the myosin head to pivot, pulling the actin filaments
inwards (power stroke).
What does this do to Z lines?
This pulls the Z lines towards each other, shortening the sarcomere.
115
Myosin cross-bridges attach
to...
... active sites on actin.
116
After attachment and ADP release, the cross-bridges ...
...pivot, pulling the thin filaments
117
A fresh ATP replaces the...
...ADP + Pi, allowing myosin and actin
to detach.
118
Energy from the splitting of the
fresh ATP allows...
...repositioning of the myosin head.
119
Cycle of muscle contraction:
1) Myosin heads hydrolyse ATP and become reoriented and energized.
2) Myosin heads bind to actin, forming crossbridges
3) Myosin crossbridges rotate toward center of the sarcomere (power stroke)
4) As myosin heads bind ATP, the crossbridges detach from actin
120
What does rigor mortis mean in latin?
stiffness of death
121
How long after death does rigor mortis commence?
Commences after 3 - 6 h
122
How many hours after death does maximum stiffness of rigor mortis occur?
10 - 14 hours
123
Rigor mortis gradually dissipates until ...
... 40 to 70 hours after death (depends on room temperature).
124
Physical Activity & Muscle Strength is related to the ...
...cross-sectional area of the muscle, not the length
125
Wider muscles have more...
...fibres, so can exert more force
126
Long muscles, however, can...
...contract further than short muscles
127
Long muscles, however, can contract further than short muscles, which causes a...
...larger and faster movement
128
The number of muscle fibres is fixed ...
...early in life
129
Muscle development in adults results from...
...thickening of the muscle fibres, not the addition of more muscle fibres
130
Anabolic steroids are taken to...
...increase muscle size by increasing protein synthesis in muscles.
131
Anabolic steroids increases...
...strength
132
Anabolic steroids is similar to...
...testosterone
133
Anabolic steroids are taken in...
...large doses
134
Anabolic steroids cause...
...damaging, even devastating effects.
135
Examples of effects of anabolic steroids?
- Liver cancer
- Kidney damage
- Stunted growth
- Increased risk of heart disease.
