Musculoskeletal Flashcards
1
Q
Muscle is classified into these three types.
A
Skeletal
Smooth
Cardiac
2
Q
Striated muscle appears “_______”.
A
Stripey
3
Q
Smooth muscle has no “______”.
A
Stripes
4
Q
Cardiac muscle is technically ________ muscle.
A
Striated
5
Q
____ junctions are utilized in muscle cells, especially in cardiac muscle.
A
Gap
6
Q
Striated muscle is typically _______ muscle, involved in ________.
A
Skeletal
Movement
7
Q
Smooth muscle is typically associated with _______, and are involved in more ________ movements.
A
Organs
Gradual
8
Q
The muscle cell is also known as a ______ _______.
A
Muscle fiber
9
Q
Organized actin/mysin strands within a muscle fiber are known as __________.
A
Myofibrils
10
Q
“Chunks” of myofibrils are known as ________.
A
Sacromeres
11
Q
T/F: Muscle skeletal muscle fibers are multinucleated.
A
True (50+ nuclei per cell)
12
Q
Why does skeletal muscle fibers have so many mitochondria?
A
“all the oxidative stuff they do” (USE LOTS OF ATP)
13
Q
The plasma membrane of a skeletal muscle fiber is known as the _________.
A
Sacrolemma
14
Q
The cytoplasm of a skeletal muscle fiber is known as the _________.
A
Sacroplasma
15
Q
The smooth ER of a skeletal muscle fiber is known as the _________.
A
Sacroplasmic reticulum
16
Q
Undifferentiated myoblasts that aid in the repair of a damaged muscle cell are called _________ _____.
A
Satellite Cells
17
Q
How do satellite cells active/differentiate
A
When the muscle they’re close to is strained or damaged.
18
Q
T/F: Satellite Cells form new muscle cells.
A
False (They fuse with the remaining cells making them bigger/stronger - otherwise referred to as Hypertrophy)
19
Q
Walk through the process of muscle repair using satellite cells.
A
Satellite cells –>
Activate with damage/injury to muscle fibers –>
Don’t form new cells but bind to remaining cells making them bigger/stronger
20
Q
List the FOUR parts of a muscle from smallest to largest.
A
Myofibrils
Muscle Fiber
Fascicle
Muscle
21
Q
Actin are _____ filaments within a muscle fiber while myosin are _____.
A
Thin
Thick
22
Q
Which shortens during a muscle contraction–
actin, or myosin?
A
Neither (They slide past each other like a sliding glass door)
23
Q
Does a muscle always shorten when it’s working?
A
No… sometimes it’s exerting force but staying the same length (e.g., when you’re holding something heavy but keeping it in place.)
24
Q
What’s going on in a muscle that’s working, but maintaining its length?
A
Cross-bridges between actin and myosin are being maintained
25
What do you call a muscle that is working but holding its length?
Isometric
26
What do you call a muscle that is working but holding its tone
Isotonic
27
These are globular polypeptides strung together in a strandlike protein like a string of pearls.
Actin
28
These are thick protein filament that’s firmly attached to the center fo a sarcomere and is immobile– HOWEVER, it has “heads” that can grab actin and pull the actin against it in a sliding motion
Myosin
29
These are another globular protein, but not a strand and are attached to actin and tropomyosin -BUT– when it binds calcium, it changes its shape and lets go of tropomyosin.
Troponin
30
This is a ropelike microtubular structure. When it’s bound to troponin, It’s wrapped around actin and covers up the sites where myosin likes to grab on. If troponin lets go of it, it moves out of the way.
Tropomyosin
31
This is stored n the smooth ER of muscle cells. When there’s very little of it around, tropomyosin is in the way of actin-myosin binding. When it’s out of the way, actin and myosin bind easily.
Ca2++
32
While a muscle is at rest, actin binding sites are covered up by _______. What can not occur at this time?
Tropomyosin
Myosin heads can not bind
33
While a muscle is at rest, tropomyosin is holding _________
Troponin
34
When a muscle fiber is stimulated by the ________ _______, each myofibirl releases stroerd _____ from its _________ ________ into the cytoplasm.
Nervous System
Ca2++
Sacroplasmic Reticulum
35
When Ca2++ is present ________ will eagerly bind to it at another bonding site. This causes he muscle fiber to _______ _______ releasing ________.
Troponin
Changes shape
Tropomyosin
36
As the tropomyosin moves out of the way, _______ _____ can now grab the ______ molecule and pull against it like a ________ _____.
Myosin heads
Actin
Sliding door
37
The process of myosin heads binding to actin molecules uses ____.
ATP
38
Myosin heads _______ ATP to ______ and use the energy to "flex and slide".
hydrolyze
ADP
39
At the end of the "flex and slide" ______ _____ releases ADP. If there is ____ present during this time, they will remain attached to their ______ site and await another _____. When another ATP arrives they grab further down the actin and do it again.
Myosin heads
Ca2++
Actin
ATP
40
Be able to to walk through the myosin/actin binding process with the "sliding filament process"
Draw This
41
What happens to myosin if Ca2++ and ATP both remmain?
Myosin will let go of Actin to grasp another ATP (Unflexes) and then grasps another actin (Flexes)
42
What happens to myosin if Ca2++ disappears?
When myosin lets go to grab another ATP, actin binding sites will become covered.
43
What happens to myosin if there is no ATP?
Myosin will remain attached to its actin binding sites (Think: Rigor Mortis)
44
What is the latent period in muscle contraction?
This allows for the "signal" (nervous stimuli) to travel through to the T-tubules in the SR and allow SR to release Ca2++
45
The release of Ca2++ is ________ while the reuptake of Ca2++ is ______
Fast
| Slow
46
The sacroplasmic reticulum specializes in the storage of _____.
Ca2++
47
T-Tubles in the SR have special voltage gated sensors called the _____ _________.
DHP Receptor
48
When the DHP receptor senses an action potential it triggers what? When this action potential is gone what happens?
The release of Ca2++ by the SR
An active transport pump within the SR uses ATP to pump Ca2++ back into the SR.
49
T/F: One motor neuron innervates many muscle fibers (cells), but one muscle fiber is innervated by only one motor neuron.
True
50
T/F: One large muscle has many motor units and the strength of contraction may depend on how many of these motor units are activated at once
True
51
The nerve cells that innervate skeletal muscle fibers are called _____ ______.
Motor Neurons
52
Motor neuron cell bodies are located where?
Brainstem or Spinal Cord (ALWAYS in the CNS)
53
What does Polio destroy?
Motor neurons
54
What are the fastest nerves in the body? (Why? )
Motor Neurons (Myleniated, Large-Diameter)
55
These give motor neurons the ability to innervate multiple muscle fibers (cells) at once
Axonic branches
56
Can you list every step of a muscle contraction, from release of Acetylcholine to contraction of the muscle?
ACh binds to receptors on motor end plate.
This binding causes a Na/K depolarization
just like in nerve cells.
Depolarization is carried through T tubules to SR
SR Releases calcium.
Calcium binds troponin.
Troponin lets go of tropomyosin.
Tropomyosin gets out of the way of myosin.
Myosin binds to actin and slides it.
Muscle contracts.
If ATP is present, this process can continue.
57
Acetylcholine receptors throughout your body are classified as _______ and ________.
nicotinic (also respond to nicotine)
muscarinic (also bind to muscarine)
58
Skeletal muscle acetylcholine receptors are _________.
Nicotinic
59
What are two ways to "turn off" a muscle?
1. Stop the action potential and get rid of the ACh that’s in the motor end plate.
2. Use the opposing muscle if necessary (antagonistic muscle groups)
60
This is an autoimmune disease that destroys nicotinic ACh receptors in skeletal muscle’s motor end plate. (up to 80% of them can be destroyed!)
Myasthenia Gravis
61
The mechanical response of a muscle fiber to a single action potential is known as a ______.
Twitch
62
A muscle fiber generates force called _______ in order to oppose a force called the ______, which is exerted on the muscle by an object.
Tension
Load
63
What are the three phases of a twitch contraction?
1. Latent period
2. Contraction phase
3. Relaxation phase
64
The latent phase of a twitch contraction occurs......
from the action potential to the onset of contraction. The time delay is due to the excitation-contraction coupling
65
The contraction phase of a twitch contraction is......
the time that tension is developing due to the cross-bridge cycling.
66
The relaxation phase of a twitch contraction is......
the time that the tension is decreasing (i.e., relaxing). It’s longer than the contraction phase because of the amount of time it takes to get all the Ca2+ sequestered.
67
_______ twitches do generate tension but do not shorten the muscle (load and force are perfectly balanced… i.e., postural muscles).
Isometric (REMEMBER: Constant Length)
68
_______ twitches do shorten the muscle, because the tension generated is greater than the load it is opposing
Isotonic (REMEMBER: Constant Tension)
69
The increase in muscle tension from successive action potentials occurring during the phase of mechanical activity is known as _________.
Summation
70
What is Tetany?
A maintained contraction in response to repetitive stimulation is known as a tetanus (tetanic contraction).
71
The decline in muscle tension is known as ______ _______.
Muscle fatigue
72
T/F: When a skeletal muscle fiber is repeatedly stimulated, the tension that the fiber can develop eventually decreases--even with continued stimulation
True
73
What occurs during muscle fatigue (Hint: Ca2++)?
The Ca2++ concentration gradient eventually moves closer to equilibrium
74
What are TWO characteristics of a fatigued muscle?
1. Decreased shortening velocity
| 2. Slower rate of relaxation
75
Why is there a slower rate of relaxation in a fatigued muscle?
There has been a higher amount of calcium released, which will take even longer to reuptake.
76
T/F: When a muscle has been fatigued, it will fatigue slower if it’s pushed soon again.
False (It will fatigue faster)
77
This is where voluntary movement orders are coordinated with other sensory and motor information.
Basal ganglia
78
This is your body’s perception of its own position and movements.
Information from the ears, eyes, and sensory organs (including muscle spindles!) is coordinated to create this “sixth sense.”
Propioception
79
_______ movements are accompanied by a conscious awareness of what we are doing.
Voluntary
80
________ movements are often characterized as unconscious, automatic or a “reflex.”
Involuntary
81
In the spinal cord, sensory information comes in __________ in the ________ _____, and motor information goes out _________ in the ________ _____.
Dorsally, posterior horn
Ventrally, anterior horn
82
T/F: Interneurons get stimuli, both excitatory and inhibitory, from multiple sites.
True
83
Only ________ messages go to the muscle.
Excitatory
84
These are specialized muscle fibers that are wrapped with the ends of sensory neurons......
Muscle spindles
85
What is the function of muscle spindles?
Detect length, and changes in length, of muscles
86
Muscles are motor organs, but they contain _______ organs within them that give your brain information about how long a particular muscle fiber is. This contributes significantly to _________.
Sensory
Proprioception
87
Painful stimulation of the skin _______ the flexor muscle and ________ the extensor muscle in the ipsilateral limb.
This same painful stimulus of the skin _______ the flexor muscle and _______ the extensor muscle on the contralateral leg. (Why?)
Activates
Inhibits
Inhibits
Activates
(Balance)
88
Sensory information is sent in an _________ pathway, while motor and autonomic information is sent in a ___________ pathway.
Ascending
| Descending
89
Planning and ongoing control of voluntary movements occurs in the ______ ______.
Cerebral Cortex
90
The parts of the cerebral cortex that act together to control muscle movement is known as the ___________ _______.
Sensorimotor Cortex
91
The interactions of the neurons within the networks are __________, capable of responding differently under different circumstances
Flexible
92
Basal ganglia manage ______ ______.
Cortical loops
93
Cortical loops send information from......
What is this information important for?
Sensorimotor cortex
Basal Nucleus
Thalamus
and back to the Sensorimotor cortex
Movement
94
This disease destroys the substantia Nigra (Part of the basal nuclei), which gives important dopamine input to the basal nuclei.
Parkinson's disease
95
Balance and smooth motion are controlled in the __________.
Cerebellum
