CH 9 & 11 Flashcards
(155 cards)
1
Q
What is the characteristic that allows muscles to pull on bones and organs to create movement called?
A
Contractility
2
Q
When muscles stretch and recoil, they recoil to a shorter length. What is this property called?
A
Elasticity
3
Q
Skeletal muscle exhibits alternating light and dark bands called
A
Striations
4
Q
Muscles that arenotunder conscious control are said to be?
A
Involuntary
5
Q
Muscle fibers are bundled together into fascicles by which connective tissue layer?
A
Perimysium
6
Q
Which property allows muscle cells to stretch to as much as three times their contracted length?
A
Extensibility
7
Q
Because skeletal muscle is under the conscious control it is said to be?
A
Voluntary
8
Q
When a muscle lengthens, the collagenous components protect the muscle because they resist?
A
Stretching
9
Q
Which muscles are not attached to bones?
A
Involuntary muscles
10
Q
Glycogen
A
a starch-like carbohydrate found in muscle cells that provides energy during intense exercise
11
Q
The innermost layer of connective tissue that surrounds each muscle fiber
A
endomysium
12
Q
Muscle and nerve cells have developed which characteristic more than other cells?
A
Excitability
13
Q
The protein found in muscle cells that stores and then releases oxygen when needed
A
Myoglobin
14
Q
Which prevents muscle cells from becoming too slack?
A
Elasticity
15
Q
Which stem cells fuse to form a muscle fiber?
A
Myoblasts
16
Q
When a muscle relaxes, elastic recoil of the collagen helps to return the muscle to its?
A
resting tension
17
Q
Which connective tissue layer surrounds the entire muscle?
A
Epimysium
18
Q
when a muscle is injured these cells can multiply and help repair the damage
A
Satellite Cells, stem cells located between a muscle fiber and the endomysium
19
Q
What is the function of T-tubules?
A
to stimulate the terminal cisternae to release calcium
20
Q
What happens to the sarcoplasmic reticulum when a skeletal myofiber is first stimulated?
A
Calcium is released into the sarcoplasm through gated channels
21
Q
Infoldings of the sarcolemma that are associated with two terminal cisternae
A
Transverse Tubules (T-Tubules)
22
Q
Which protein makes up the thick filaments of a myofibril?
A
Myosin
23
Q
4 Components of Thin Filaments
A
Fibrous (F) actin , Globular (G) actin, Tropomyosin, and Troponin
24
Q
Which membranous structures conduct impulses through the sarcoplasm to stimulate the release of calcium?
A
T-tubules
25
Elastic filaments in a myofibril are made of which protein?
Titin
26
What are the end-sacs of the sarcoplasmic reticulum called?
Terminal Cisternae
27
Which is found in thin filaments but is not a regulatory protein?
Actin
28
A thick filament is composed of pairs of this molecule, intertwined together
Myosin
29
What happens when calcium ions bind to troponin?
Tropomyosin moves off the active site on actin
30
Thin filaments are primarily composed of which protein?
F actin
31
What is the function of T-tubules?
To stimulate the terminal cisternae to release calcium / carry the action potential through the sarcoplasm
32
Which protein links actin fibers to the inner face of the sarcolemma?
Dystrophin
33
What stabilizes thick filaments and prevents over-stretching?
Elastic filaments
34
In a thin filament, each tropomyosin molecule has a small calcium-binding protein bound to it called
Troponin
35
What are two regulatory proteins found in a myofibril?
Tropomyosin and Troponin
36
Under the microscope, muscle that has alternating light and dark regions is said to be
Striated
37
Within a sarcomere, the overlap of actin and myosin produce what bands?
A Bands (anisotropic) , dark bands
38
A genetic condition in which an abnormal form of the dystrophin protein is produced
Muscular Dystrophy
39
Within a sarcomere, what is the region within the A band that lacks thin filaments?
H band
40
What is the portion of a myofibril from one Z disc to another called?
Sarcomere
41
Which type of neuron controls a skeletal muscle cell?
Somatic motor neuron
42
What causes skeletal muscle cells to be striated?
the alternating light and dark regions of the sarcomeres
43
What do all the muscle fibers innervated by a single nerve fiber constitute?
a Motor Unit
44
When are large motor units used?
Where physical strength is needed
45
What are light bands in skeletal muscle called?
I bands that are bisected by Z discs
46
A synapse is the point where a nerve fiber meets a target cell. When the target cell is a muscle fiber, what is this synapse called?
Neuromuscular Junction (NMJ)
47
Each muscle fiber is innervated by how many motor neurons?
Only one motor neuron per muscle cell
48
A neuromuscular junction is a type of what?
Synapse
49
What is a motor unit?
All of the muscle fibers innervated by a single motor nerve fiber
50
Within a synapse, a neuron ends in a swelling called?
an axon terminal
51
What are smaller motor units used for?
Fine motor control
52
What is the neurotransmitter used in a neuromuscular junction?
Acetylcholine (ACh)
53
I bands are composed primarily of which protein?
Actin (thin filaments)
54
What is a neuromuscular junction?
A site where a nerve fiber communicates with a muscle fiber
55
What is the indented region of the sarcolemma that participates in the neuromuscular junction called?
Motor end plate
56
What are the folds in the sarcolemma at the neuromuscular junction called?
Junctional folds
57
The synaptic knob does not touch the muscle fiber but is separated by which structure?
Synaptic cleft
58
What do neurons and muscle cells have in common?
Their membranes undergo voltage changes when stimulated
59
What is acetylcholine?
The neurotransmitter released at a neuromuscular junction
60
What is the difference in electrical charge from one point to another called?
electrical potential or voltage
61
What is the change in membrane potential with the entry of sodium ions called?
Depolarization
62
During an action potential, the loss of potassium ions from the cell results in what?
Repolarization
63
The junctional folds of the neuromuscular junction are the site of which receptors?
Acetylcholine (ACh) receptors
64
Which cells have plasma membranes that undergo voltage changes in response to stimuli?
Neurons and muscle cells
65
The quick up and down voltage shift from negative to positive, created by the movement of Na and K cations across the cell membrane is called what?
Action potential
66
the voltage measured across the muscle cell at rest is about -90mV and is called what?
the Resting Membrane Potential (RMP)
67
What is excitation?
Excitation involves the generation of action potentials, and occurs in both neurons and muscle fibers
68
During depolarization of a muscle cell or nerve cell, ion channels in the plasma membrane open allowing which ions to enter the cell?
Sodium
69
When a nerve signal arrives at a synaptic knob, which voltage-gated channels open in the knob?
Calcium channels
70
During repolarization, which ions diffuse out of the cell, changing the membrane potential back to a negative value?
Potassium
71
When Ach binds to its receptors on the motor end plate, an ion channel opens and which ions diffuse quickly into the muscle cell?
Sodium
72
Where does the end-plate potential occur?
Motor end plate
73
What is action potential?
A rapid fluctuation in the membrane potential following stimulation
74
Which phase of contraction links the action potential in the sarcolemma to the activation of the myofilament?
Excitation-contraction coupling
75
The process by which action potentials in a nerve fiber lead to action potentials in a muscle fiber is called what?
Excitation
76
What must occur before tropomyosin can shift, revealing the active sites that allow myosin heads to bing to the actin filaments?
Calcium must bind to troponin
77
What potential causes the opening of ion channels, which results in the initial movement of sodium and potassium across the plasma membrane at the neuromuscular junction. If continued, this in turn can trigger an action potential at the neighboring sarcolemma.
The end-plate potential
78
What is the step in which the muscle fiber develops tension and may shorten?
Contraction
79
What is the name of the prevailing theory regarding muscle contraction?
Sliding filament theory
80
The "cocking" of the myosin head, hydrolysis of ATP and the power stroke occur during which phase of skeletal muscle contraction?
Contraction
81
What does Myosin ATPase do?
it is found in the myosin head and hydrolyzes ATP to release energy
82
What occurs when calcium binds to troponin?
The troponin-tropomyosin complex changes shape and exposes the myosin binding sites (G active sites)
83
During contraction, the cocked myosin head binds to an exposed active site onto the actin protein of what?
The thin filament, forming a cross-bridge
84
The overlapping of myofilaments increases during what?
Muscle contraction
85
During contraction, what causes a power stroke?
When myosin releases ADP and ratchets to a low energy position
86
During contraction, each power stroke consumes one molecule of what?
ATP
87
The cross-bridge created by the binding of a myosin head to an active site on an actin filament is broken by binding what?
ATP
88
Which stage of contraction occurs when the myosin releases ADP and flexes, pulling the thin filament toward the M line?
Power stroke
89
What forms a cross bridge?
The cocked head of myosin bound to actin
90
The Steps of Muscle Relaxation
1) The nerve signal ceases
2) AChE breaks ACh down
3) Active transport pumps in the sarcoplasmic reticulum begin to pump calcium back into the cisternae
4) Calcium releases from troponin
5) Tropomyosin covers the myosin binding sites
91
What is the enzyme that breaks down acetylcholine?
Acetylcholinesterase (AChE)
92
How much does a muscle fiber shorten from a single cycle of power and recovery strokes by all the myosin heads?
1% of its resting length
93
What does the Sarcoplasmic Reticulum do from excitation through contraction?
Releases and reabsorbs calcium continuously
94
What is the hydrolysis of ATP and preparation for reattachment to the thin filament by the myosin head called?
The Recovery stroke
95
Why does a filament stay in place when a single myosin head releases?
Because hundreds of other myosin heads are still attached
96
In which phase does muscle tension decline and sarcoplasmic calcium levels fall?
Relaxation
97
During which phase of muscle contraction is calcium transported back into the cisternae and tropomyosin moves back to block the actin active sites?
Relaxation
98
What is the role of acetylcholinesterase?
It breaks down ACh, ending muscle stimulation
99
After contraction, what causes muscles to return to their resting length?
Elastic elements within the sarcomere
100
During relaxtion, calcium is actively pumped back into what?
the sarcoplasmic reticulum/ terminal cisternae
101
What is a lever?
an elongated structure that is utilized to generate a mechanical advantage around a fulcrum
102
Within skeletal anatomy levers, what supplies the effort?
Muscle contraction
103
Within skeletal anatomy levers, what serves as the resistance?
Muscle tone, the weight of an object being manipulated, or the weight of the lever itself
104
What is mechanical advantage?
the ratio of a lever's output force to its input force
105
Within a musculoskeletal lever system, what is the fulcrum?
Joints
106
If a lever's mechanical advantage is 1.0 or greater, what does it produce?
the lever produces more FORCE (but less speed or distance) than the force exerted on it
107
If a lever's mechanical advantage is less than 1.0 what does the lever produce?
it prodcues more speed or distance (but less force) than the force exerted on it
108
What is a 1st Class Lever?
Fulcrum is between resistance and effort (RFE)
109
What is a 2nd Class lever?
Resistance is between Fulcrum and Effort (FRE)
110
What is a 3rd Class lever?
Effort is applied between the fulcrum and resistance (FER). MOST MUSCULOSKELETAL LEVERS ARE 3RD CLASS
111
Sitting in a chair and raising one thigh is an example of what class of lever system?
2nd Class Lever
112
Which factors allow the shoulder to have a wide range of motion?
Loose joint capsule and shallow joint cavity
113
What is the Glenoid Labrum?
fibrocartilage structure that increases the depth of the glenoid cavity
114
4 muscles of the Rotator Cuff (muscles that stabilize shoulder joint)
Subscapularis, Infraspinatus, Supraspinatus, and Teres Minor (these muscles' tendons form the rotator cuff)
115
In TMJ, which ligament prevents posterior displacement of the mandible?
Lateral Ligament
116
What is the joint that is the articulation between the arm and the shoulder?
Glenohumeral joint
117
What are the 3 ligaments that support the shoulder joint?
Trasnverse humeral, glenohumeral, and coracohumeral ligaments
118
What bursae cushion muscles and tissues within the shoulder joint?
The subdeltoid, subacromial, subcoracoid, and subscapular bursae
119
What is the function of the Olecranon Bursa?
cushions movement of tendons over the posterior aspect of the elbow joint
120
What are the 2 ligaments that restrict side to side movements of the elbow joint?
Ulnar and Radial Collateral ligaments
121
Which joint occurs in the elbow region but is not part of the hinge joint?
Proximal Radioulnar joint
122
What is the function of the Anular Ligament?
Holds head of the radius within the radial notch of the ulna
123
Which ligament bridges the gap in the inferior margin of the acetabular labrum?
Transverse Acetabular ligament
124
Where is the Round Ligament (teres) found and where does it connect?
Found within the hip joint, runs from the acetabulum to the fovea capitis
125
The patellofemoral joint is an example of what class of synovial joint?
Gliding (plane) joint
126
The medial and lateral patellar retinacula are part of which muscle?
Quadriceps femoris
127
Which joint is the most complex diarthroses in the body?
The Knee
128
Which aspect of the knee joint is not covered by the joint capsule?
Anterior
129
The primary stabilizing structures of the knee include the tendons from which muscles?
Quadriceps and Semimembranosus tendons
130
What is the function of the Menisci?
to absorb shock and prevent the femur from moving side to side on the tibia
131
What is the superficial ligament located on the medial surface of the knee?
Tibial Collateral ligament
132
What aspects (sides) of the knee does the joint capsule cover?
Only the posterior and lateral aspects of the knee
133
What is the function of the posterior cruciate ligament?
To prevent the tibia from being displaced backward
134
What are the menisci of the knee composed of?
Fibrocartilage
135
Hyperextension of the knee is prevented by which ligament?
Anterior Cruciate Ligament (ACL)
136
Locking the knee causes what to be twisted and taught?
Ligaments
137
What are the 4 anterior bursae of the knee?
Suprapatellar, Superficial infrapatellar , Deep infrapatellar, and Prepatellar bursae
138
What is the ankle joint also referred to as?
The Talocrual Joint
139
In order to lock the knee, what direction does the femur rotate?
Medially
140
Within the ankle joint, what motion is reduced by the malleoli (bumps of ankle bone) of the tibia and fibula?
Side to side motion
141
Which ligament binds the fibula to the foot on the lateral side of the ankle?
Lateral collateral ligament
142
The calf muscles cause plantar flexion of the foot via what tendon?
The Achilles/calcaneal tendon
143
What is the role of the anterior and posterior tibiofibular ligaments?
To bind the tibia to the fibula
144
Which ligament binds the tibia to the foot on the medial side of the ankle?
Deltoid Ligament
145
What is arthritis?
joint pain and inflammation
146
What is Bursitis?
inflammation of a bursa
147
What is Dislocation?
displacement of a bone from its normal position (separation of articular surfaces at a joint)
148
What causes gout?
A build up of uric acid. Produces sharp, paintful crystals in synovial fluid
149
What is Rheumatism?
general term for conditions characterized by inflammation and pain in joints, muscles, and associated structures
150
What is a sprain?
a tear in a ligament or tendon
151
What is a strain?
injury caused by overstretching a tendon or muscle
152
What is Synovitis?
inflammation of a joint capsule
153
What is Osteoarthritis?
results from wear and tear of bones. VERY common in people over 70
154
What is Rheumatoid Arthritis?
an auto immune disease that causes inflammation in synovial joint fluid and deterioration of joints
155
What structures may be affected by rheumatism?
Muscles, tendons, bones, and ligaments
