Exam 2 Flashcards
MASTER (88 cards)
1
Q
skeletal muscle
A
- Highly plastic and responsive tissue
- Modulated by usage and age
- Growth (+ or -) depends upon the balance of protein synthesis or degradation
2
Q
Behavioral properties of musculotendinous unit
A
- extensibility
- elasticity
- irritability
- ability to develop tension
3
Q
what is extensibility?
A
ability to be stretched or to increase in length
4
Q
what is elasticity?
A
ability to return to normal resting length following a stretch
5
Q
components of elasticity
A
parallel elastic component and series elastic component
6
Q
what is parallel elastic component?
A
passive elasticity derived from muscle membranes
7
Q
what is series elastic component?
A
passive elasticity derived from tendons when a tensed muscle is stretched
8
Q
what is irritability?
A
ability to respond to a stimulus
9
Q
what is ability to develop tension?
A
the contractile component of muscle function
10
Q
viscoelasticity
A
- Ability to stretch when a constant force is applied.
- Force developed when stretched to a constant length will dec. over time
11
Q
What is a motor unit?
A
- single motor neuron and all fibers it innervates
- considered the functional unit of the neuromuscular system
12
Q
muscle fiber type 1
A
slow contraction, slow fatigue, small diameter, low ATP, High mitochondria conc., low glycogen
13
Q
muscle fiber Type 2a
A
fast contraction, mid fatigue, mid diameter, high ATP, high mitochondria conc., mid glycogen
14
Q
muscle fiber type 2b
A
fast contraction, fast fatigue, big diameter, high ATP, low mitochondria conc., high glycogen
15
Q
contraction types
A
concentric: shortening
eccentric: lengthening
isometric: no change
16
Q
muscle roles
A
agonist: acts to cause a movement
antagonist: acts to slow/stop movement
stabilizer: acts to stabilize a body part against a force
neutralizer: acts to eliminate unwanted action produced by agonist
17
Q
when resistance (force) is negligible
A
muscle contracts with maximal velocity
18
Q
as load increases
A
concentric velocity slows to zero at isometric max
19
Q
muscle length-tension relationship
A
tension in a stretched muscle = active tension provided by muscle fibers and passive tension provided by tendons/membranes
20
Q
How do we measure muscular strength?
A
The amount of torque a muscle group can generate at a joint
21
Q
what is torque?
A
moment of force (rotary effect of a force or the angular equivalent of a force)
22
Q
T = Fd
A
the product of force and the perpendicular distance from the force’s line of action to the axis of rotation
23
Q
what affects muscular strength
A
- distance between muscle attachment to bone and joint center
- angle of the muscles attachment bone
24
Q
what is muscular endurance
A
- the ability to exert tension over a period of time
- the opposite of muscle fatigability
25
what is anthropometry
- studies physical measurements of human body
- determines differences in individuals and groups
- ethnic, gender, age, body type
26
Mass - anthropometric
- as WB mass inc. so does segment mass
- segment mass can be found using imaging
- segment mass expressed as % of WB mass
27
Density - Anthropometric
- whole body and segment
- measured using BodPod. Segment volume w/ density table. imaging/scanning techniques
28
Whole Body Density - anthropometric
average density a function of body type
29
segment density - anthropometric
each segment is a combo of bone, fat, muscle, connective tissue. Not uniform
30
what is specific gravity?
ratio of density of a substance to the density of a standard.
31
specific gravity of cortical bone
1.8
32
specific gravity of muscle
just above 1
33
specific gravity of fat
<1
34
specific gravity of lungs
<<1
35
Center of Mass
- equilibrium or balance point
- utilized for kinetic & energy calculations
- dependent on geometry and density
36
WB Center of Mass
Since segments are in motion, CoM and WB continuously change over time
37
how to calculate CoM
xM=(m1x1 + m2x2 + m3x3)/M
yM=(m1y1 + m2y2 + m3y3)/M
M = mass of whole segment
(x,y) = CoM
38
what is stability?
resistance to disruption of equilibrium
39
What is balance?
ability to control equilibrium
40
What is the base of support?
area bound by outermost regions of contact between body and support surface
41
what can increase body stability?
- inc. body mass
- inc. friction
- inc. size of base of support
- horizontally positioning center of gravity near edge of base support on side of external force
- vertically positioning center of gravity as low as possible
42
what is a lever
simple machine consisting of a relatively rigid bar-like body that can be made to rotate around an axis or a fulcrum
43
3 classes of levers
first, second, third (review notes for image of them)
44
mechanical advantage of levers
ratio of the moment arm of the force (force arm) to the moment arm of the resistance (resistance arm) for a given lever
45
mechanical advantage equation
aF/bR
aF = force distance from fulcrum
bR = resistance distance from fulcrum
46
what is static equilibrium
a motionless state in which there is no net force or net torque acting
47
Newton's first law of linear kinematics
a body will remain in a state of rest or constant velocity unless acted on by an external force
48
Newton's second law of linear kinematics (F=ma)
a force applied to a body causes acceleration of that body
- of a magnitude proportional to the force
- in direction of the force
- and inversely proportional to body's mass
49
Newton's third law of linear kinematics
- for every action, there is an equal and opposite reaction
- when one body exerts a force on a second, the second body exerts a force that is equal in direction on the first body
50
what is momentum
quantity of motion possessed by a body
- M = mv
51
principle of conservation of momentum
in absence of external forces, the total momentum of a given system remains constant
- M = M
- (mv)1 = (mv)2
52
impulse
product of a force and the time interval over which the force acts
53
relationship between impulse and momentum
- Ft = deltaM
- M = mv
- Ft = (mv)2 - (mv)1
54
types of impact
perfectly elastic impact and perfectly plastic impact
55
perfectly elastic impact
in which the velocity of the system is conserved (e=1)
56
perfectly plastic impact
in which there is a total loss of a system velocity (e=0)
57
what is mechanical work?
product of force applied over a distance
- W = Fd
- units are Joules
58
What is mechanical Power
rate of work production
- P = W/t or P=Fd/t
- units are Watts
59
what is mechanical energy
capacity to do work
- units are Joules
three forms: kinetic, potential, thermal
60
kinetic energy
energy of motion
- KE = 1/2mv^2
61
potential energy
energy by virtue of a body's position or configuration
- Pe = mgh
62
netwon's 1st law: law of angular inertia
a rotating body will maintain a state of rest or constant rotational motion unless acted on by an external torque that changes the state
63
newton's second law: the law of angular acceleration
A net torque causes angular acceleration of a body that is:
- of a magnitude proportional to the torque
- in the direction of the torque
- and inversely proportional to the body's moment of inertia
- T = la
64
newton's third law: law of angular reaction
- for every angular action, there is an equal and opposite angular reaction
- when ones body exerts a torque on a second, the second body exerts a reaction torque that is equal in magnitude and opposite in direction of the first body
65
what is the moment of inertia?
- the inertial property for rotating bodies
- represents resistance to angular acceleration
- based on both mass and the distance the mass is distributed from the axis of rotation
66
angular impulse
the product of torque and the time interval over which the torque acts:
- Tt = deltaH
- Tt = (lw)2 - (lw)1
67
structures of Nervous system for controlling movement
- cerebral cortex
- basal ganglia
- cerebellum
- brainstem
- spinal cord
67
cerebral cortex
- main center for control
- uses info from other centers in CNS & feedback to bring movements under voluntary control
68
basal ganglia
- essential role in selective initiation of activities and suppression of unwanted movements
69
cerebellum
- vital for control of rapid movements
- loss leads to uncoordinated movements
70
brainstem (pons)
- provides background contraction of postural muscles to provide support against gravity
- connects spinal cord to the cerebral cortex
71
spinal cord
- more than just a conduit for signal conduction
- region for peripheral execution of movements
- integrative area for spinal reflexes and automatic motor functions
72
transmitting information
- vast number of neurons
- need to communicate very rapidly
- carried out by:
- electrical and chemical signals
73
electrical signal =
action potential
74
action potential
- changes in current flow in the nerve cell
- propagation of the signal along the axon
- necessary condition: must have a resting potential
75
sending signals: muscle contraction
- what is a motor unit?
- single motor neuron and all fibers it innervates
- considered the functional unit of the neuromuscular system
76
How does CNS receive information on movements?
Sensors
- length, tension
- rate of change
muscle spindles
- static and dynamic response
golgi tendon organs (GTO)
- sensory receptor in the tendon
77
muscle spindle
- detect length and rates of change in length
- transmit info to the cord
- signal proportional to the degree of stretch
- firing rate increases for stretch, decreases for shortening
- prevents overstretching by causing contraction
78
GTO
- detects tension and rate of change in tension
- relative muscle tension
- stimulated with increase in tension
- prevents tearing of muscle muscle by causing reflex relaxation
79
location of golgi tendon organs
within tendons near the muscle-tendon junction in series with muscle fibers
80
location of muscle spindles
- interspersed among muscle fibers in parallel with the fibers
81
stimulus of golgi tendon organs
increase in muscle
82
stimulus of muscle spindles
increase in muscle length
83
response of golgi tendon organs
1. inhibit tension development in muscle
2. initiate stretch by tension development in antagonist muscles
84
response of muscle spindles
1. initiate rapid contractino of stretched muscle
2. inhibit tension development in antagonist muscles
85
overall effect of golgi tendon organs
promote stretch in muscle to reduce tension
86
overall effect of muscle spindles
inhibit stretch in muscle by increased tension
87
force velocity relationship
the greater the velocity, the less force produced
