joint structure and muscle function Flashcards
1
Q
Wolff’s law
A
bones will adapt based on stress or demands placed on them
2
Q
joints are classified based on what 2 things
A
structure type
movement
3
Q
3 structure types of joint classification
A
fibrous
cartilaginous
synovial
4
Q
3 movement types of joint classification
A
synarthrosis
amphiarthrosis
diarthrosis
5
Q
synarthrosis + example
A
immobile/nearly immobile joint
ex: SI joint or sutures in skull
6
Q
amphiarthrosis + example
A
joint allows SOME movement –> has balance between mobility and stability
ex: spine at different levels (lumbar moves in different way than thoracic and cervical)
7
Q
diarthrosis + example
A
free moving
ex: shoulders, hips
8
Q
fibrous joints
A
joined together by fibrous interosseous connective tissue
9
Q
suture joint
A
bone edges interlock one another
10
Q
gomphosis joint
A
“peg in a hole” joint
like tooth and mandible/maxilla
11
Q
syndesmosis joint
A
joined by interosseous ligament
ex: radius and ulna
or tibia and fibula
12
Q
cartilaginous joints
A
connected by fibrocartilage or hyaline cartilage
13
Q
symphysis joint
A
directly joined by fibrocartilage and covered with hyaline cartilage
ex: intervertebral joints + pubis symphysis
14
Q
synchondrosis joint
A
connected by HYALINE cartilage
ex: first 7 ribs to sternum
or epiphyseal growth plates
15
Q
synovial joints
A
no connective tissue directly unites bony surfaces
16
Q
function of inner synovial layer of a synovial joint
A
provides lubrication, vascularization, and nutrition to the cartilage
17
Q
characteristics of the outer fibrous layer of a synovial joint
A
dense, irregular connective tissue
varying thickness
poor vascularity + good innervation (wont bleed but it’ll hurt when you tear it)
18
Q
ruffini joint receptor function
A
reacts to stretch/extremes of extension
19
Q
pacini joint receptor function
A
compression/changes in hydrostatic pressure and joint movement
20
Q
golgi (GTOs) joint receptor function
A
pressure + forceful joint motion into extremes of motion
21
Q
unmyelinated free nerve ending joint receptor function
A
painful and unpainful mechanical stress or biomechanical stress
22
Q
hyaluronate
A
viscosity of fluid and essential for lubrication
23
Q
lubricin
A
cartilage on cartilage lubrication
24
Q
t/f: nutrients and waste products diffuse in and out of synovial fluid
A
true
25
t/f: volume of synovial fluid decreases at an injured joint
false, it increases
26
which 2 joint receptor picks up increased pressure of an injured joint and signals
pacini + unmyelinated free nerve endings pick up the pain from this type of injury
27
function of menisci, labrums, and discs (3)
improve joint congruence
absorb compressive joint forces
increase stability
28
ligament functions (2)
align joint surfaces
guide/restrain motion
29
tendon functions (2)
transmit forces developed by muscles for motion
active joint stabilization
30
bursae function
protect soft tissue from shear force/friction of bones
31
hinge and pivot joints are examples of what classification of synovial joint
uniaxial
32
condyloid and saddle joints are examples of what classification of synovial joint
biaxial
33
ball-and-socket and plane joints are examples of what classification of synovial joint
triaxial
34
plane joint example
intercarpal joint
35
condyloid joint example
radiocarpal joint
36
saddle joint example
first carpometacarpal joint (thumb)
37
pivot joint example
proximal radioulnar joint
38
osteokinematics
movement of bones for physiologic joint motion
(plane, axis, and direction of movement; ex: flx/ext, ab/adduct,etc)
39
arthrokinematics
movement of the joint surfaces
(roll, slide/glide, spin)
40
open chain
movement takes place at one joint without causing motion at another joint
DISTAL segment is moving
41
closed chain
movement at one joint causes motions at other joints
PROXIMAL segment is moving
42
convex on concave movement
roll and glide occur in opposite directions
ex: humerus on scapula abduction --> roll inferior, slide superior
43
concave on convex
roll and glide occur in same direction
ex: tibia on femur extension --> roll anterior and slide anterior
44
close-packed
- full congruence of surfaces
-extreme ROM
- joint is compressed and no more movement can occur
ex: patella with knee flexion cannot move
45
loose/open-packed
- incongruent surfaces
- mid-position
- allows for spin, roll, glide
- max loose packed position is at REST
45
soft end-feel
limited by soft-tissues
ex: elbow flexion
46
firm end-feel
limited by capsuloligamentous structures
ex: knee extension
47
hard end-feel
limited by bone
ex: elbow extension
48
cell that has a primary function of synthesizing the extracellular matrix
fibroblasts
49
3 types of fibroblasts
chondroblasts
tenoblasts
osteoblasts
50
2 components of the extracellular matrix
fibrillar component
interfibrillar component
51
fibrillar component of extracellular matrix is made of...
- elastin
- type I collagen to provide strength and functional integrity
52
interfibrillar component of extracellular matrix is made of...
proteoglycans and glycosaminoglycans
- that attract water to increase rigidity
- withstand compressive forces
53
what type of collagen primarily makes up ligaments and tendons
type I
54
collagen fiber alignment in tendons vs ligaments
ligaments = all directions
tendons = straighter
55
what type of collagen primarily makes up hyaline cartilage
type II
56
what type of collagen primarily makes up fibrocartilage
type I
57
hyaline cartilage
- on joint surfaces
- resists compressive forces
- avascular
58
fibrocartilage
- resists compressive AND tensile forces
- limited vascularity peripherally
(think discs + meniscus)
59
cancellous vs cortical bone
cancellous is the spongy inner layer
cortical is the compact outer layer
60
periosteum
fibrous membrane that covers the surface of bone
61
what type of collagen makes up bone
type I
62
isotropic material
display the same mechanical behavior no matter the direction of force applied
63
anisotropic material
behave differently depending on the size and direction of applied force
64
toe region of mechanical behavior
laxity in tissue straightens
65
elastic region of mechanical behavior
returns to original shape and size after being deformed
66
yield point region of mechanical behavior
point of no return
67
plastic region of mechanical behavior
residual deformation will be permanent
68
failure point of mechanical behavior
tear or break
69
tensile strain
forces pulling in opposite directions
70
shear loading
parallel forces pushing in opposite directions
71
torsional stress
parallel forces rotating in opposite directions
72
strain equation
(L2-L1) / L1
L1 = original length
L2 = final length
73
stiffness
resistance offered by material to external loads
74
brittle
little deformation before failure (older bone)
75
ductile
great deformation before failure (younger bone)
76
elastic region strain %
2-4%
77
plastic region strain %
4%-7.9%
grade I + II ligament sprains
78
young's modulus
measurement of structure's ability to withstand changes in length
79
macrofailure
rupture or avulsion
80
viscosity
resistance to flow (more fluid)
high viscosity = high resistance to deformation
81
how does temperature impact viscosity
high temperatures DIMINISH viscosity
82
elasticity depends on 2 things:
amount of collagen and elastin
83
creep
tissue deformation gradually continues if force is maintained
(ex: weight on elastic band)
84
stress-relaxation:
as tissue is stretched to a fixed length, less force is required to maintain that length overtime
85
stain-rate sensitivity
tissue response varies based on load speed
rapid load --> stiffer tissue
86
are tendons or ligaments more susceptible to tensile stress?
ligaments are
87
are tendons or ligaments better with multiple direction loading?
ligaments are
88
muscle stability is greatest in close or open packed positions?
close-packed
bones are most congruent so its easier to stabilize
89
2 components of a myofibril
actin
myosin
(myofilaments)
90
titin
maintains position of myosin during muscle contraction
91
z-discs
link together actin
92
a band
the contractile unit of the myofibril
93
I bands
only actin filaments
94
H zone
only myosin filaments
95
cross bridge interaction
1. action potential
2. Ca2+
3. troponin
4. actin becomes free
5. myosin binds w actin
96
motor unit
alpha motor neuron and all muscle fibers it innervates
97
active muscle tension is affected by 4 things:
1. # of muscle fibers in a motor unit
2. diameter of the axon innervating motor unit
3. # motor units firing at one time
4. frequency of motor units firing
98
type IIA muscle fibers
fast oxidative glycolytic (INTERMEDIATE)
99
type IIB muscle fibers
fast glycolytic
(FATIGUES THE QUICKEST OUT OF ALL FIBERS)
100
superficial fascia function
contributes to mobility of skin and acts as insulator
101
deep fascia function
attach to muscle/bones and can form tracts, bands, or retinaculae
102
passive elastic component
adds passive tension and stiffness through connective tissue and tendons
103
stretching a muscle is considered to be what form of tension
passive
104
contracting a muscle is considered to be what form of tension
active
105
active insufficiency
decreased force capability due to a shortened state of agonist
106
active insufficiency is influenced by...
lengthening the state of the antagonist muscle
ex: flex fingers in neutral vs flexing fingers in wrist flexion
107
is force greater in eccentric, isometric, or concentric contractions
eccentric
108
label eccentric, isometric, and concentric contractions with a +,-, or 0 contractile velocity:
eccentric: -
isometric: 0
concentric: +
109
concentric vs eccentric
concentric is a shortened contraction with positive work
eccentric is a lengthening contraction with negative work (thing E for Elongation)
110
torque production varies with what 3 things
moment arm length
force length
velocity
111
isokinetic
constant angular velocity by changing torque through ROM
112
reverse action
proximal segment moves while distal segment remains stationary
like a pull-up
113
5 classifications for muscles
shape
number of heads
location
function
action or length of moment arm
114
antagonists have 2 jobs
reciprocal inhibition (allows agonist to contract)
co-contraction (stability)
115
passive insufficiency
the antagonist is not long enough to allow full ROM of all joints
116
wrist extension causing finger flexion is an example of what body mechanism
(bonus for the spinal level injury that uses this technique to grab things)
passive insufficiency
(c6)
117
muscle function if distal attachment lies CLOSE to the joint axis
rotation
118
muscle function if distal attachment lies AWAY from the joint axis
compression/stability
119
2 stretch reflexes
deep tendon reflex (GTO)
muscle spindle reflex
120
muscles in a SHORTENED position will __(increase/decrease)__ the NUMBER of sarcomeres and __(increase/decrease)__ the LENGTH of sarcomeres
decrease
length increase
121
muscles in a LONG position will __(increase/decrease)__ the NUMBER of sarcomeres and __(increase/decrease)__ the LENGTH of sarcomeres
increase
length decrease
122
when a muscle is lengthened for a long period of time, what direction does the tension curve shift? (left/right)
right!!
