LESSON 2 - skeletal muscle & human movement 1 Flashcards
skeletal muscle & human movement 1
1
Q
What are the three types of muscle ?
A
Skeletal
Smooth
Cardiac
2
Q
Describe skeletal muscles and their location
A
Voluntary and Skeleton
3
Q
Describe smooth muscles and their location
A
Involuntary and within hollow organs
4
Q
Describe cardiac muscles and their location
A
Involuntary and located within the heart
5
Q
Describe the anatomy of muscles from the bone
A
Bone - tendon - muscle - fascicle - muscle fibres - muscle fibre - myofibril
6
Q
How are bones attached to muscles ?
A
Tendon
7
Q
What is the thin layer of the muscle tissue called ?
A
Epimysium
8
Q
What is the fascicle surrounded by ?
A
The perimysium
9
Q
What are muscle fibres made of ?
A
Bundle of myofybrils
10
Q
Which layer is the epimysium ?
A
Outermost
11
Q
Which layer is the endomysium ?
A
Under
12
Q
Which layer is the perimysium ?
A
Between
13
Q
What do skeletal muscles consist of ?
A
75% water, 20% protein, and the remainder is salts, enzymes, pigments, fats and carbohydrates
14
Q
Name a trick to remember the order of muscles ;
A
Bigger the name, the smaller it is
15
Q
What is a muscle fibres made up of ?
A
Bunch of myofibril
16
Q
Between thick and thin filaments which one moves ?
A
Thin (actin)
17
Q
Between thick and thin filament which one is actin /myosin ?
A
Thin = actin
Thick = myosin
18
Q
What part of the sarcomere never has interaction with myosin ?
A
H zone
19
Q
Which between the A band and H zone interacts with actin/myosin ?
A
A band
20
Q
Which moves the thick or thin filament ?
A
Thin (actin)
21
Q
Which does not move, the thick or thin filament ?
A
Thick (myosin)
22
Q
What do myofilaments do ?
A
Allow muscles to contract
23
Q
Which part of the myofilament have troponin ?
A
Actin
24
Q
What binds to troponin causing the power stroke ?
A
Myosin heads
25
Where do the myosin tails and heads point toward ?
Tails = towards centre of sarcomere
Heads = sides of the myofilament band
26
What is actin attached to ?
The Z-line
27
Which is on the outside / inside between actin and myosin ?
Myosin in the middle and actin on the outside
28
the average muscle fiber contains how many sarcomeres ?
4500 sarcomeres
29
the average muscle fiber contains how many myosin ?
16 billion
30
the average muscle fiber contains how many actin filaments ?
64 million
31
a full muscle is made up of a bunch of ...
muscle fascicles
32
between actin and myosin which has troponin surrounding them ?
actin
33
what does the mitochondria do within the muscle structure ?
produces energy
34
how does the mitochondria produce energy within the muscle structure ?
consuming oxygen
35
what is the sarcoplasm within the muscle structure ?
space that surround (fluid filled space)
36
what is the sarcolemma ?
membrane of the cell
37
what are the t-tubles within the muscle structure ?
(essentially) electrical wires
38
where do the t-tubules connect ?
connect from the brain to sarcoplasmic reticulum in regards to calcium
39
what does the sarcoplasmic reticulum do within the muscle structure ?
wraps around each myofibril
40
what triggers a muscle contraction ?
calcium
41
which type of muscle requires us to think about performing an action ?
the skeletal muscle system
42
what are the four main parts of the neuronal system that regulates movement in regards to the skeletal muscles ?
- brain
- spinal cord
- nerves
- t-tubles
43
which pathway does the neuronal system travel ?
descending (motor) pathway
44
between dorsal and ventral which is anterior / posterior ?
dorsal = posterior
ventral = anterior
45
what are the three major divisions of the nervous system ?
1. brain and spinal cord
2. cranial and spinal nerves
3. somatic and visceral neurones
46
what do somatic and visceral neurones do ?
conduct impulses from receptors to CNS
47
which two systems work ascending and depending of each other ?
CNS and PNS
48
which two branches does the peripheral nervous system branch into?
sensory (afferent) nerves and effector (efferent) nerves
49
what do motor neurons do ?
conduct impulses from CNS to effectors
50
what two branches does the effector (efferent) nerves branch into ?
autonomic and somatic
51
between autonomic and somatic which is involuntary / voluntary ?
autonomic = involuntary
somatic - voluntary
52
"conduct impulses from CNS to cardiac/smooth muscle and glands"
involuntary
53
"conduct impulses from CNS to skeletal muscles"
voluntary
54
what two branches does the autonomic system branch into ?
sympathetic and parasympathetic
55
"fight or flight"
sympathetic
56
"rest and digest"
parasympathetic
57
what is a motor unit ?
single motor neuron and all the muscle fibers it innovates
58
within each muscle fiber how many neurons are present in each ?
one neuron
59
describe how the motor neuron travels starting from the spinal cord ...
spinal cord - motor neuron (cell body) - travels descending through nerve - motor unit 1 - motor neuron axon - travel to its own individual muscle fiber
60
TRUE OR FALSE
"one impulse can innervate many different muscles fibers"
true
61
TRUE OR FALSE
"each muscle fiber generally receives input from only one neuron, yet a motor neuron may innervate many muscle fibers because the terminal end of an axon forms numerous branches"
true
62
define in your own words "neuromuscular junction"
nervous system & muscular system
63
where do nerve impulses travel ?
travel down axon
64
what is released at the axon terminal of neuromuscular junction ?
ACh
65
what does ACh stand for ?
Acetylcholine
66
what do myofibrils store ?
calcium
67
what does ACh trigger ?
an electrical potential on the sarcolemma
68
what happens if an electrical excitation threshold is reached ?
an AP is triggered
69
what happens what a transmembrane voltage is created ?
changed membrane potential
70
what does ACh do in regards to potassium and sodium ?
changes permeability of membrane to sodium and potassium
71
what helps release ACh at the synaptic vesicle ?
calcium
72
where is the action potential traveling through the neuromuscular junction ?
going down nerve
73
what happens once ACh binds to a ACh receptor ?
triggers a current that travels down / activates the t-tubles
74
what type of wave is traveling down the t-tubles ?
wave of depolarization
75
the wave of depolarization traveling down the t-tubles stimulates what ?
the sarcoplasmic reticulum
76
what does the sarcoplasmic reticule release once it is triggered by the wave of depolarization ?
calcium
77
what is the importance of calcium being released by the sarcoplasmic reticulum ?
allowing for actin / myosin to interact and cause a contraction
78
where does ACh travel from the synaptic vesicle ?
travels across the synaptic clef and binds
79
why do muscle fibres shorten ?
because myosin and actin interact in a way that generates tension and allows sliding of the filaments past each other without myofilaments changing length
80
what serves as the molecular motor to drive fiber shortening ?
energy from ATP
81
where does energy from muscles come from ?
ATP
82
what are the two states of how muscles create movement ?
relaxed state and contracted state
83
define the relaxed state ...
- no actin-myosin interaction occurs at binding site
- myofilaments overlap a little
84
define the contracted state ...
- myosin head pulls actin toward sarcomere center (power stroke)
- filaments slide past each other
- sarcomeres, myofibrils, muscle fibers all shorten
85
how many steps are there in the power stroke preform a power stroke ?
6
86
which step of the power stroke is "in the ready state, the myosin cross-bridge is tightly bound at a 45 degree angle to the actin filament"
1
87
which step of the power stroke is "ATP binds to myosin allowing it to release from the actin filament"
2
88
which step of the power stroke is "ATPase on the myosin hydrolyses that ATP to access energy, and the myosin head moves away from the actin filament. ADP and Pi remain bound to myosin"
3
89
which step of the power stroke is "the myosin head moves to 90 degrees and binds to a new actin molecule"
4
90
which step of the power stroke is "the myosin head released Pi, which initiates the power stroke, where it tilts back to 45 degrees, pulling the thin filament toward the center of the sarcomere"
5
91
which step of the power stroke is "after the power stroke the myosin head releases ADP and returns to the ready state. this process continues until the ends of the myosin filaments reach the Z-disks, or until Ca is pumped back into the SR"
6
92
what does myosin need in order to bind ?
ATP
93
what does calcium interact with in order to initiate a contraction ?
troponin
94
why does calcium need to interact with troponin ?
to release the binding site
95
what does it mean if an individual has less ACh ?
gets fatigued quicker
96
AP travelling down the t-tubels triggers the release of _____
calcium
97
does a release of calcium cause increase of force ?
yes
98
what is a biodex machine ?
measures force stimulating nerve to get a twitch
99
is there a "max" where sarcomeres can no longer be contracted ?
yes
100
within the length-tension relationship graph how many steps are there ?
5
101
what force is it when "↓ crossbridge interactions + ↑ shortening capability"
force 1
102
what force is it when "↑ crossbridge interactions + ↑ shortening capabilities"
foce 2, 3 and 4
103
what force is it when "↑crossbridge interactions + ↓ shortening capability "
force 5
104
what happens when pushing & pulling (of muscle and physical structure) is occurring ?
↑ APs = ↑ crossbridge interactions = ↑ shortening = ↑ force
105
if you have more AP what does this mean for force ?
more AP = greater force
106
what are dynamic contractions ?
muscle contractions with a fixed amount of weight
107
what are the three types of dynamic contractions ?
isometric, concentric and eccentric
108
what is isometric ?
no movement
109
what is concentric ?
shortening / flex
110
what is eccentric ?
lengthening / extended
111
how do we calculate force (N) specifically ?
load (kg) x gravitational constant (9.81m/s^2)
112
within a force-velocity relationship high force + ___ velocity ...
low
113
within a force-velocity relationship big weight (mass) = ___ acceleration ...
low
114
how do we calculate force (N) simplified ?
mass x acceleration
115
how do we calculate power ?
power = force x velocity
116
what is fatigue ?
a loss in the capacity of the muscle to develop force and/or velocity resulting from muscle activity under load
117
how is fatigue reversible ?
reversible by rest
118
how does fatigue occur ?
from interrupting the chain of events between the CNS → PNS → NMF → muscle fibers
119
what are some examples that can lead to fatigue in muscles ?
-reduced stored muscle energy (glycogen)
- impaired calcium release and re-uptake
- disturbance in T-tubles
- alterations in CNS neurotransmitters
120
