Test 3 Flashcards
1
Q
Of skeletal, cardiac, and smooth, which is striated?
A
Skeletal and cardia
2
Q
Of skeletal, cardiac, and smooth, which can can contract spontaneously?
A
Cardiac and smooth
3
Q
Which type of neuron innervates skeletal muscle? Smooth muscle?
A
Skeletal- Somatic Motor
Smooth- Autonomic
4
Q
A tendon connects
A
muscle to bone
5
Q
A ligament connects
A
bone to bone
6
Q
Which type of muscle cell is multinucleate?
A
Skeletal
7
Q
______ moves bones closer together
A
flexion
8
Q
If an extensor muscle contracts, the angle between bones
A
increases
9
Q
Do muscle cells have inhibitory neurons?
A
No
10
Q
What is the connective tissue that surrounds fibers?
A
fascia
11
Q
Fascia is bundled into ______
A
fascicles
12
Q
The cell membrane of a muscle cell is the
A
sarcolemma
13
Q
A triad is formed from
A
One T-tubule between two terminal cisternae
14
Q
Myofibrils are composed of _____ and _____ filaments.
A
thick, thin
15
Q
Thick filaments include
A
Myosin, Titin, Nebulin
16
Q
Thin filaments include
A
Actin, Troponin, Tropomyosin
17
Q
A myofibril is surrounded by ______ ______ and is packaged into ______.
A
Sarcoplasmic Reticulum, fibers
18
Q
Describe Myosin
A
A motor protein composed of two separate heads: a light chain and a heavy chain
19
Q
Because the Heavy Chain of Myosin cleaves a phosphate group from ATP, it is also known as
A
Myosin ATPase
20
Q
What is the site of ATP binding and release
A
Actin
21
Q
How is the sarcomere defined
A
the thick and thin filaments between two adjacent z-disks
22
Q
1 thick filament is surrounded by ______ thin filaments and 1 thin filament is surrounded by ______ thick filaments
A
Six, three
23
Q
Which types of muscle have T-tubules?
A
Cardiac, Skeletal
24
Q
Is a T-tubule part of the intracellular compartment?
A
No
25
What are the two contractile proteins? Regulatory Proteins? Accessory Proteins?
Actin, Myosin. Troponin, Tropomyosin. Titin, Nebulin
26
Titin helps with with alignment of Thick filaments with thin filaments, and its elasticity returns muscles to Resting Length.
True
27
When a muscle contracts, ______ shorten
Sarcomeres
28
What can bind to Troponin?
Calcium ions, Tropomyosin, Actin
29
What is the cascade that occurs when intracellular calcium is increased inside a myofibril? Where does this calcium come from?
Calcium binds to Troponin, Troponin moves tropomyosin away from Myosin ATPase, Myosin ATPase can bind to Actin, Power Stroke activates. Sarcoplasmic Reticulum
30
Describe the contraction cycle.
ATP binds to MATPase and is hydrolyzed into ADP. Intracellular Ca increases, Phosphate group is released, Heavy chain binds to Actin, Head contracts, Moves thin filament, ADP is released into ECF at end.
31
When is the Myosin ATPase in the "Cocked Position"?
After ATP is hydrolyzed into ADP & P.
32
What triggers intracellular calcium release?
Generation of End Plate Potential
33
What receptors are found on the muscle end plate? What is the Neurotransmitter?
Nicotinic. Acetylcholine.
34
What happens in the T-Tubule after ACh is released on a motor end plate?
An end plate potential is generated and Local current flow flows down the T-tubule.
35
What receptor is typically located at the bottom of a T-Tubule?
Dihydropyridine Receptors
36
What is the dihydropyridine receptor linked to and what does it do when an end plate potential is generated?
Ryanodine Receptor. This receptor releases intracellular calcium from the SR.
37
What are the components of Excitation-Contraction Coupling?
ACh binding with its receptor initiates Na channels to open, causing a depolarization in the muscle and eventual contraction.
38
Does K exit through the same channels as Na?
Yes
39
What enzyme forces Calcium back into the SR?
SER Calcium ATPase
40
What enzyme initiates relaxation?
SER Calcium ATPase
41
Which is faster? Neuron AP or Muscle AP?
Neuron
42
What has greater Hyperpolarization? Neuron AP or Muscle AP?
Neuron
43
How long is the contraction and relaxation phase of a muscle?
10-100 msec.
44
What are the three components of a muscle twitch? What causes the Latent Period?
Contraction, relaxation phase, Latent period. Duration of contraction cycle.
45
What is used as a buffer for ATP levels?
Phosphocreatine
46
What is the breakdown of skeletal Muscle?
Rhabdomyolysis
47
What enzyme phosphorylates ADP from phosphocreatine?
Creatine Kinase
48
ATP is needed for (in muscles)...
1) Crossbridge formation, release,
2) SERCA pumps
3) Na K ATPase pumps
49
What encompasses central fatigue?
Psychological Effects, protective reflexes.
50
What enzyme phosphorylates creatine from ATP?
Creatine Kinase
51
What are the three subsets of Skeletal Muscle?
Fast twitch Glycolytic, Fast twitch Oxidative, Slow twitch
52
Which subset of skeletal muscle is the most vascularized?
Slow twitch
53
What molecule is highly present in oxidative fibers?
Myoglobin
54
Which fibers subset is dependent on Glycolysis for ATP production?
Fast twitch Glycolytic
55
Which fiber has the smallest diameter of the subsets?
Slow twitch
56
What happens when the resting length is greater than optimum? Less than optimum?
Few crossbridges are formed, decreases tension. Thin filaments begin to overlap preventing crossbridge formation.
57
Can Contractions sum their tension? Why?
Yes, because the Time of contraction is much greater than the Time of EPP, full relaxation cannot occur, and therefore can continually be stimulated without falling tension.
58
What is the difference between complete and incomplete tetanus?
Incomplete has a slight relaxation while Complete has No time for relaxation. Aint got no time for that!!!
59
What encompasses a motor unit?
The motor neuron and the fibers it innervates
60
Is one fiber only innervated by one motor neuron?
| Can a motor neuron innervate multiple muscle fibers?
Yes. Yes.
61
Can there be mixed subsets of skeletal muscle in a motor unit?
No.
62
How does the body compensate for increased load?
Recruitment of additional fibers
63
How does the body allow sustained contractions?
Asynchronous Recruitment
64
Which type of contraction moves loads?
Isotonic
65
If you perform a plank (holding a stable lateral position against the force of gravity), what type of contractions are you performing?
Isometric
66
Which type of contraction produces force?
Both types
67
If an isotonic contraction shortens the fibers and the sarcomeres, what does a isometric contraction shorten?
It shortens the elastic elements and the sarcomeres.
68
_____ _____ is inversely proportional to increased load and is variable with muscle type.
Contraction Speed
69
How is smooth muscle categorized?
Location, Contraction Pattern, Communication
70
How do single unit smooth muscles contract?
Through Gap Junctions
71
Which type of smooth muscle is periodically contracted?
Phasic
72
If you have a smooth muscle cell that is located in the enteric system, is usually contacted to some degree, and does not have gap junctions, what would be the description of this muscle?
Enteric, Tonic, multi-unit
73
How many nuclei are present in a smooth muscle cell?
one
74
Can Smooth muscle be multidirectional? Can skeletal muscle?
Yes. No.
75
Between smooth and skeletal, which contracts faster?
skeletal
76
Between smooth and skeletal, which subset of the PNS is each in?
Smooth in autonomic, Skeletal in Somatic
77
Between smooth and skeletal, where are the receptors located?
Smooth- all over
| Skeletal- motor end plate
78
Between smooth and skeletal, which has troponin?
Skeletal
79
Between smooth and skeletal, which has greater amounts of actin
Smooth
80
Between smooth and skeletal, which has greater amounts of myosin
Skeletal
81
What are the approximate analogues of z disks and T-tubules in smooth muscle?
Dense bodies, Caveolae
82
Between smooth and skeletal, what does calcium bind to?
Skeletal- troponin
| Smooth- calmodulin
83
What is the result of Calmodulin receiving Calcium ions?
Myosin LC is phosphorylated
84
If MLC is phosphorylated, what occurs in the MHC?
Its activity increases.
85
What is the primary determinate of the force generated in smooth muscle?
Amount of MLCK
86
Slow wave potentials generate APs when...
their membrane potentials reach threshold
87
Where are slow wave potentials only found?
GI tract
88
Describe pacemaker potentials
Cells automatically depolarize to threshold (generate APs) at constant intervals
89
Because smooth muscle does not have the ability to recruit more units, how does it grade contractions?
Alter the intracellular Calcium concentration
90
How does smooth muscle increase intracellular calcium?
By opening Voltage, ligand or Mechanical gates; by Creating 2nd messenger IP3 to bind with SR; by allowing calcium to trigger the RyR to release calcium from SR
91
Are all Autonomic reflexes polysynaptic?
yes
92
If a reflex has at least one interneuron it is a _____ reflex.
polysynaptic
93
How is muscle stopped from contracting?
Somatic neurons are inhibited
94
Alpha motor neurons innervate _____ fibers while _____ _____ neurons inhibit Intrafusal fibers.
Extrafusal, Gamma motor
95
Intrafusal fibers are...
responsible for controlling and sensing stretch
96
Name the three proprioreceptors
Joint Receptors, Golgi tendon organs, Spindles
97
Are spindles always active?
yes
98
What allows muscle spindles to always be stretched even when the extrafusal fibers are contracted?
Alpha- gamma coactivation. Gamma motor neurons innervate intrafusal fibers when Alpha motor neurons innervate extrafusal fibers.
99
Spindles restore arm position by initiating _____. Golgi tendon organs prevent damage to muscles by...
Contraction. Exciting Inhibitory interneurons to alpha motor neurons to relax a muscle
100
The patellar tendon reflex is a _____ reflex
monosynaptic
101
Crossed extensor reflex moves the body away from a painful stimulus with one limb and supports posture of the body with the other limb
true
102
_____ tracts innervates muscles for voluntary movements and reflex pathways
Corticospinal tracts
103
Where do corticospinal tracts decussate?
In the pyramids
104
How are females generalized?
Reproductive partner with larger gamete.
104
Why is the egg so big?
Needs nutrients for development
105
What does a sex cell do during division?
During prophase one,
