Muscle Tissue Flashcards
1
Q
Responsive to chemical signals, stretch, and electrical changes across the plasma membrane
A
Excitability
2
Q
local electrical excitation sets off a wave of excitation that travels along the muscle fiber.
A
Conductivity
3
Q
shortens when stimulated
A
Contractility
4
Q
capable of being stretched between contractions
A
Extensibility
5
Q
returns to its original rest length after being stretched
A
Elasticity
6
Q
voluntary, striated muscle usually attached to bones of the skeleton. Striations
A
skeletal muscle
7
Q
Connective tissue wrappings
A
Endomysium
Perimysium
Epimysium
8
Q
connective tissue around muscle cell
A
Endomysium
9
Q
connective tissue around muscle fascicle
A
Perimysium
10
Q
connective tissue surrounding entire muscle
A
Epimysium
11
Q
attach the muscle to the bone
A
tendons
12
Q
plasma membrane of a muscle fiber
A
Sarcolemma
13
Q
cytoplasm of a muscle fiber
A
Sarcoplasm
14
Q
types of sacroplasm
A
myofibrils
glycogen
myoglobin
15
Q
long protein cords occupying most of sarcoplasm
A
Myofibrils
16
Q
packed into spaces between myofibrils
A
Mitochondria
17
Q
smooth ER that forms a network around each myofibril
A
Sarcoplasmic reticulum (SR)
18
Q
tubular infoldings of the sarcolemma which penetrate through the cell and emerge on the other side
A
T tubules
19
Q
a T tubule and two terminal cisterns associated with it
A
Triad
20
Q
made of several hundred myosin molecules, each molecule shaped like a golf club. Two chains intertwined to form a shaft-like tail and a double globular head. The heads are directed outward in a helical array around the bundle. The heads on one half of the thick filament angle to the left, while heads on other half angle to the right. The bare zone is the area in the middle with no heads.
A
Thick filaments
21
Q
two intertwined strands made up of string of globular (G) actin subunits each with an active site that can bind to head of myosin molecule.
A
Thin filaments
22
Q
segment from Z disc to Z disc
A
Sarcomere
23
Q
Darkest part is where thick filaments overlap a hexagonal array of thin filaments
A
A band
24
Q
not as dark; middle of A band; thick filaments only
A
H band
25
middle of H band
M line
26
means light
I band
27
provides anchorage for thin filaments and elastic filaments
Z disc
28
A bundle of protein myofilaments within a muscle fiber; Each surrounded by sarcoplasmic reticulum and mitochondria. Has a banded (striated) appearance due to orderly overlap of protein myofilaments.
Myofibril
29
A segment of myofibril from one Z disc to the next in the fiber’s striation pattern.
Sarcomere
30
Fibrous protein strands that carry out the contraction process.
Myofilaments
31
cannot contract unless stimulated by a nerve
Skeletal muscle
32
one nerve fiber and all the muscle fibers innervated by it
Motor unit
33
have about three to six muscle fibers per neuron which allows for
fine degree of control.
Small motor units
34
have hundreds of fibers allowing for more strength than control. Leads to powerful contractions.
Large motor units
35
Small motor units examples
Eye and hand muscles
36
Large motor units examples
Quadriceps femoris and gastrocnemius
37
point where a nerve fiber meets its target cell.
synapse
38
gap between axon terminal and sarcolemma
Synaptic cleft
39
a terminal branch at the end of the part of synpatic neuron
synaptic knob
40
A disease where an individual lacks Ach receptors leading to weakness.
Myasthenia Gravis
41
What sets the resting membrane potential (RMP) and how does the cells change from unstimulated to stimulated muscle fiber
potassium concentration gradient
42
about −90 mV in skeletal muscle cells which is maintained by sodium–potassium pump.
Resting membrane potential
43
Tetanus toxin blocks the release of glycine which in the spinal cord normally stops motor neurons from producing unwanted muscle contractions and overstimulation.
Tetanus (lockjaw)
44
a state in which the muscles are limp and cannot contract
Flaccid paralysis
45
plant poison used by South American natives to poison blowgun darts competes with ACh for receptor sites but does not stimulate the muscles. Leads to flaccid paralysis.
Curare
46
type of food poisoning caused by a neuromuscular toxin secreted by the bacterium Blocks release of ACh causing flaccid paralysis.
Botulism
47
Four major phases of contraction and relaxation
Excitation
Excitation–contraction
Contraction
Relaxation
48
a process in which nerve action potentials lead to muscle action potentials
excitation
49
events that link the action potentials on the sarcolemma to activation of the myofilaments, thereby preparing them to contract
Excitation–contraction coupling
50
the step in which the muscle fiber develops tension and may shorten
Contraction
51
when stimulation ends, a muscle fiber relaxes and returns to its resting length
Relaxation
52
the amount of tension generated by a muscle depends on how stretched or shortened it was before it was stimulated
Length–tension relationship
53
a quick cycle of contraction and relaxation when stimulus is at threshold or higher.
Twitch
54
very brief delay between stimulus and contraction
Latent period
55
time when muscle generates external tension
Contraction phase
56
time when tension declines to baseline
Relaxation phase
57
an increase in tension that occurs when each successive stimuli is delivered after the relaxation phase of the preceding twitch.
Treppe
58
higher frequency stimuli produce what
temporal (wave) summation
59
Each new twitch rides on the previous one generating higher tension with only partial relaxation between stimuli.
wave summation
60
Higher frequency stimuli with each new twitch riding on the previous twitch. Only partial relaxation between stimuli till it reaches maximum level of tension.
Incomplete Tetanus
61
Unnaturally high stimulus frequencies (in lab experiments) cause a steady, contraction and muscle never begins to relax.
Complete (fused) Tetanus
62
Muscle produces internal tension but external resistance causes it to stay the same length.
Isometric muscle contraction
63
Muscle changes in length with no change in tension.
Isotonic muscle contraction
64
muscle shortens as it maintains tension
Concentric contraction
65
example of concentric contraction
lifting weights
66
muscle lengthens as it maintains tension
Eccentric contraction
67
example of eccentric contraction
slowly lowering weight
68
Two main pathways of ATP synthesis
Anaerobic fermentation
Aerobic respiration
69
enables cells to produce ATP in the absence of oxygen; yields little ATP and lactate, which needs to be disposed of by the liver.
Anaerobic fermentation
70
produces far more ATP; does not generate lactate; requires a continual supply of oxygen.
Aerobic respiration
71
Short, intense exercise (100 m dash): Oxygen is briefly supplied by myoglobin but is rapidly depleted.
Immediate Energy
72
Two enzyme systems control these phosphate transfers in immediate energy
1. Myokinase
2. Creatine Kinase
73
supply oxygen to the cells in your muscles
myoglobin
74
transfers Pi from one ADP to another, converting the latter to ATP
Myokinase
75
the combination of ATP and CP which provides nearly all energy for short bursts of activity. Enough energy for 6 s of sprinting.
Phosphagen system
76
uses carbohydrates (glucose) stored in the muscles as Glycogen
Glycogen lactic acid system
77
what type of breathing is Short-Term Energy
Anaerobic Fermentation
78
what type of breathing is Long-Term Energy
Aerobic Respiration
79
As the phosphagen system is exhausted, muscles shift to anaerobic fermentation
Short-Term Energy- Anaerobic Fermentation
80
how much energy does Short-Term Energy- Anaerobic Fermentation produce
30–40 s of maximum activity
81
After about 40.s, the respiratory and cardiovascular systems start to deliver oxygen fast enough for aerobic respiration to meet most of muscle’s ATP demand
Long-Term Energy -Aerobic Respiration
82
progressive weakness from prolonged use of muscles
muscle fatigue
83
is major determinant of one’s ability to maintain high-intensity exercise for more than 4–5 min
Maximum oxygen uptake (VO2 max)
84
the point at which the rate of oxygen consumption plateaus and does not increase further with added workload
VO2 max
85
meets a metabolic demand also known as oxygen debt.
Excess Post-exercise Oxygen Consumption (EPOC)
86
is the difference between the elevated rate of oxygen consumption following exercise and the usual resting rate.
Oxygen debt
87
Three major types of skeletal muscle fibers
- Fast fibers (fast glycolytic)
- Slow fibers (slow oxidative)
- Intermediate fibers
88
what type of twitch is well adapted for endurance; resist fatigue by oxidative (aerobic) ATP production
Slow-twitch (slow oxidative)
89
what kind of muscles has slow-twitches (slow oxidative)
muscles that maintain posture
(ex: erector spinae of the back, soleus of calf)
90
white, or type II fibers
Fast-twitch (Fast glycolytic)
91
what kind of muscles has fast-twitches (Fast glycolytic)
quick and powerful muscles
(ex: eye and hand muscles, gastrocnemius of calf and biceps brachii)
92
what type of twitch is well adapted for quick responses
Fast-twitch (Fast glycolytic)
93
Contraction of a muscle against a load that resists movement
Resistance training
94
what is an example of resistance training
weightlifting
95
Improves fatigue-resistant muscles
Endurance training (aerobic exercise)
96
Properties of cardiac muscle
- Contracts with regular rhythm
- works at anytime
- resistant to fatigue
- cells contract in unison
97
can contract without need for nervous stimulation
Cardiac muscle
98
Uses aerobic respiration almost exclusively, rich in myoglobin and glycogen.
cardiac muscle
99
named for its lack of striations
smooth muscle
100
lack nerve supply; others receive input from autonomic fibers with many varicosities containing synaptic vesicles
smooth muscle
101
what type of twitch does cardiac muscles exhibit
slow
102
Takes longer to contract but can remain contracted for a long time without fatigue
smooth muscle
103
how does smooth muscle contract
is always triggered by Ca2+, energized by ATP, and achieved by sliding filaments
104
how does smooth muscle get excited
- Autonomic activity
- Hormones, carbon dioxide, oxygen, and pH
- Temperature
- Stretch
- Audtorhythmicity
105
group of hereditary diseases in which skeletal muscles degenerate and weaken, and are replaced with fat and fibrous scar tissue
Muscular dystrophy
106
Autoimmune disease in which antibodies attack neuromuscular junctions and bind ACh receptors together in clusters and are then removed so that the fibers become less sensitive to Ach
Myasthenia Gravis
