Chapter 9 Flashcards
1
Q
what type of muscle:
tissue is striated. voluntary- somatic. it moves the body
A
skeletal
2
Q
what type of muscle:
tissue is striated. involuntary - visceral. pushes blood through cardiovascular system
A
cardiac
3
Q
what type of muscle:
tissue is not striated. involuntary- visceral. pushes fluid and solids along the digestive tract and regulates diameters of arteries among other functions
A
smooth
4
Q
What are the functions of skeletal muscle tissue?
A
produce body movement, maintain posture and body position, support soft tissue, guard body entrances/exits, maintain body temperature, store nutrients.
5
Q
What does producing body movement do?
A
muscle tendons pull and move joints
6
Q
What does maintaining posture and body position do?
A
stabilize joints
7
Q
What does supporting soft tissue do?
A
surround, support, and shield internal structures
8
Q
What does guarding body entrances and exits do?
A
sphincters encircle openings, provide voluntary control
9
Q
How does maintaining body temperature work?
A
contraction uses the heart
10
Q
Define fascicle
A
bundle of muscle fibers
11
Q
Define muscle fibers
A
a single muscle cell
12
Q
Define sarcolemma
A
plasma membrane of a skeletal muscle fiber (cell)
13
Q
Define sacroplasm
A
cytoplasm of muscle fiber
14
Q
Define myofibril
A
small cylindrical structures arranged parallel inside muscle fibers; run length of muscle fiber
15
Q
What is the organization of connective tissue?
A
- Epimysium ‘
- Perimysium
- Endomysium
16
Q
Dense sheath of collagen fibers that surround the entire muscle. Separates muscle from surrounding tissue
A
Epimysium
17
Q
Surrounds muscle fiber bundles aka fascicles. Contains blood vessels and nerve supply to fascicles
A
Perimyisum
18
Q
Surrounds individual muscle cells aka muscle gibers. Contains capillaries and nerve fibers containing muscle cells. Contains my-satellite cells (stem cells) that help repair damaged muscle tissue
A
Endomysium
19
Q
The endomysium, perimysium and epimysium come together at the ends of muscles to form ________
A
tendons or aponeurosis
20
Q
The sarcolemma is the _______ _________ of a muscle fiber (cell).
A
plasma membrane
21
Q
The sarcolemma surrounds the ___________. (cytoplasm of a muscle fiber)
A
sarcoplasm
22
Q
A change in the transmembrane potential begins a __________ _________.
A
muscle contraction
23
Q
Transverse tubules (T Tubules) transmit the ______ _______ through the cell, allowing the entire muscle fiber to contract simultaneously.
A
action potential
24
Q
Myofibrils are made up of bundles of protein filaments called
A
myofilaments
25
Myofilaments are responsible for what?
muscle contractions
26
Thin filaments- made of the protein:
actin
27
Thick filaments- made of the protein:
myosin
28
A membranous structure that surrounds each myofibril
the sarcoplasmic reticulum
29
The sarcoplasmic reticulum help to transmit the _______ _______ to the _______.
action potential, myofibril
30
Smallest functional units of muscle fibers
Sacromeres
31
the dark, thick filaments are called
A bands
32
the light, thin filaments are called
I bands
33
The A band:
| the center of the A band. At midline of sacormere
M line
34
The A band:
| the are around the M line. Has thick filaments but no thin filaments.
H band
35
The A band:
| the denest, darkest area on a light micrograph. Where thick and thin filaments overlap
Zone of Overlap
36
The I band:
| the centers of the I band. At two ends of sarcomere
Z lines
37
The I band:
| strands of elastic protein. reach from tips of thick filaments to the Z lines. Stablizies the filaments
Titin
38
Thin Filaments:
| 2 twisted rows of globular G actin that hold the active sites which will bind with myosin
F-actin
39
hold the F-actin strands together
Nebulin
40
Thin Filaments:
| a double strand that covers the active sites
Tropomyosin
41
Thin Filaments:
| A globular protein that binds to tropomyosin, controlled by Ca2+
troponin
42
Initating a muscle contraction:
1. Ca2+ will bing to a receptor in tropnin
2. Troponin will then cause tropomyosin to move out of the way and expose the active sites on the F-actin so that the active sites can bind with myosin heads.
43
Thick filaments contain about 300 twisted ______ subunits.
myosin
44
Thick filaments contain ______ strands that recoil after stretching
titin
45
The myosin molecule has a
tail and head
46
myosin molecule:
| face M line, free heads face out toward thin filaments. Binds to other myosin molecules
tail
47
myosin molecule:
| reaches the nearest thin filaments
head
48
Thin filaments of sarcomere slide toward _ _____, alongside _________.
M line, thick filaments
49
Skeletal muscle contraction in 3 steps
1. Neural simulation of sarcolemma
2. Muscle fiber contraction
3. Tension production
50
Excitation- Contraction Coupling (6 steps)
1. Neural Control
2. Excitation
3. Calcium ion release
4. Contraction Cycle Begins
5. Sacromeres shorten
6. Muscle tension produced `
51
What step of Excitation- contraction coupling?
action potential in motor neuron starts
1. Neural Control
52
What step of Excitation- contraction coupling?
action potential causes each release from motor neuron. Leads to excitation (action potential) in sarcolemma.
Excitation
53
What step of Excitation- contraction coupling?
action potential travels through sarcolemma into T-tubules to the triad triggering the release of stored Ca2+ from the terminal cistern of sacroplasmic reticulum
Calcium ion release
54
What step of Excitation- contraction coupling?
during a muscle contraction, the entire skeletal muscle shortens and produces tension on the tendons at either end of the muscle
Muscle tension produced
55
Describe the Contraction Cycle
1. Resting sarcomere
2. Contraction cycle begins
3. Active-site exposure
4. Cross-bridge formation
5. myosin head formation
6. Cross bridge detachment
7. Myosin reactivation
56
What step in the contraction cycle:
Myosin heads are all "energized" and "cocked". Cocking head requires breakdown of ATP. Myosin head acts as ATP base; ADP and P stay attached to head.
Resting sarcomere
57
What step in the contraction cycle:
Begins with the arrival of calcium from the sarcoplasmic reticulum to the zone of overlap
Contraction cycle begins
58
What step in the contraction cycle:
Calcium binds to troponin which moves trpopmyosin out of the way, exposing active sites on actin
Active- site exposure
59
What step in the contraction cycle:
Once active sites are exposed, energized myosin heads bind them forming cross-bridges
Cross- Bridge formation
60
What step in the contraction cycle?
Myosin head pivots toward M line (cause shortening). This is the power stroke. When this happens, ADP and P are released
Myosin Head Pivots
61
What step in the contraction cycle?
A new ATP attaches to each myosin head, myosin head releases from actin. Active sites are available to form another cross-bridge
Cross bridge detachment
62
What step in the contraction cycle?
Myosin head is "reactivated" when the ATP splits into ADP and phosphate. This re-cocks the myosin head.
Myosin reactivation
63
2. Contraction cycle begins;
| Begins with the arrival of _______ from the scaroplasmic reticulum to the zone of overlap.
calcium
64
3. Active-Site exposure
| Calcium binds to troponin which moves tropomyosin out of the way, exposing ______ _______ on ______.
active sites on actin
65
4. Cross-bridge formation
| Once active sites are exposed, energized _______ heads bind to them forming _________
myosin, cross-bridges
66
5. Myosin head pivoting
Myosin head pivots toward M line (cause shortening). This is called the ______ ______. When this happens, ADP and P are released.
power stroke
67
7. Myosin reactivation
| Myosin head is "reactivated" when the ATP splits into ____ and ______. The re-cocks the myosin head.
ADP and phosphate
68
When does the cycle repeat?
while Ca2+ is high and ATP is available
69
The Ca2+ stay high only if:
action potentials continue
70
When stimulus ends, SR calcium channels ______
close
71
When stimulus ends, Ca2+ releases from ________ and returns into terminal cistern of the ____
troponin and SR
72
A fixed muscular contraction after death
Rigor Mortis
73
rigor mortis is caused when ion pumps can't function because they run out of _____
ATP
74
Rigor mortis is caused when calcium builds up in the __________.
sarcoplasm
75
broad sheet with broad attachment to bone
Aponeurosis
76
Tension production depends on the optimal resting length of a ________.
Sarcomere
77
The optimal resting length of a sarcomere is the length where a maximum number of ________ can form.
cross-bridges
78
The optimal resting length of a sarcomere produces the
most tension
79
Muscle Twitch Steps
1. Latent Period
2. Contraction phase
3. Relaxation phase
80
Action potential stimulates sacrolemma. Calcium released from sacroplsmic reticulum. No tension yet
Latent period
81
Calcium binds to troponin. Cross-bridge
Contraction phase
82
Calcium drops, cross bridges detach; active sites covered. Tension returns to resting levels
Relaxation phase
83
single motor neuron and all muscle fibers it controls
motor unit
84
activation of more motor unites to produce
recruitment
85
achieved when ALL motor units reach tetanus
Maximum tension
86
less than maximum tension and allows motor units to rest in rotation (asynchronous motor unit summation)
Sustained tension
87
the normal tension of a muscle at rest
muscle tone
88
muscle tone allows muscle units to actively maintain body position ________ motion
without
89
As tension rises, skeletal muscle length _______(there is movement with the same tension)
changes
90
What type of muscle contraction?
| skeletal muscle length changes
isotonic
91
Isotonic Muscle Contraction:
| muscle tension rises until exceeds load. as muscle shortens, the tension then remains constant.
concentric
92
muscle tension ______ until exceeds load
rises
93
As muscle shortens, the tension then remains ______.
constant
94
What type of muscle contraction:
skeletal muscle develops tension but NO change in length. Tension can change but length can't.
Isometric
95
Is muscle relaxation a active or passive process?
passive
96
What force?
| the pull of elastic elements (tendons and ligaments). Expands the sarcomeres to resting length
elastic forces
97
What force?
| reverse the direction of the original motion. Are the work of opposing skeletal muscle pairs
opposing muscle contraction
98
What force?
| can take the place of opposing muscle contraction to return a muscle to its resting state
gravity
99
Source of ATP in muscles
anaerobic breakdown of glucose to pyruvate.
location:cytosol
oxygen is not required
2 ATP produced
glycolysis
100
Sources of ATP in muscles
location: mitochondria
Produce 38 ATP molecules per glucose molecule
Aerobioc metabolism
101
How many ATP's does aerobic metabolism produce?
38
102
How many glycolysis does ATP produce?
2
103
Energy reserves in a typical skeletal muscle fiber
1. Glycogen
2. Free ATP
3. Glycolysis
4. Aerobic metabolism
104
when muscle cannon longer perform a required activity
muscle fatigue
105
What is the major factor in muscle fatigue?
decreased pH
106
Muscle fatigue decreases
calcium/troponin binding
107
Muscle fatigue alters
enzymes activités
108
amount of oxygen required to restore normal, pre-exertion conditions
oxygen debts
109
in the recovery period, _________ becomes available
oxygen
110
What fiber:
```
diameter: large
time to tension: rapid
contraction speed: fast
fatigue: rapidly
color:white
mitochondria: few
```
fast fibers
111
What fiber:
```
diameter: half diameter of fast
time of tension: prolonged
contraction speed: slow
fatigue: not as quick
color: dark red
mitochondria: high
```
slow fibers
112
What fiber:
```
diameter: intermediate
time of tension: medium
contraction speed: fast
fatigue: more resistant to fatigue than fast fibers
color: pink
mitochondria: high
```
intermediate fibers
113
muscle enlargement =
muscle hypertrophy
114
decreased muscle size, tone and power=
muscle atrophy
115
Virus attacks CNS motor neurons causing atrophy and paralysis.
Polio
116
surpasses the inhibition of motor neuron activity
tetanus
117
affect neuromuscular communication
Botulism
118
affect neuromuscular communication. Autoimmune disease causing loss of Ach receptors at neuromuscular junctions. Results in progressive muscualar weakness
Myasthemia gravis
