Muscles Pt. 2 Flashcards
1
Q
What are the 3 sources of energy in muscle?
A
- Carbohydrates.
- Free Fatty Acids (FFA).
- Phosphocreatine.
2
Q
What source of energy is the most readily available?
A
Phosphocreatine (PCr).
3
Q
A
3
Q
What is phosphocreatine?
A
A high energy phosphate group similar to ATP.
4
Q
How do PCr and ADP interact?
A
In the presence of creatine kinase, PCr donates a phosphate group to the ADP to form ATP.
*Reversible reaction.
5
Q
What is the second most utilized/available method for ATP production?
A
Glycolysis.
6
Q
What are the two types of glycolysis?
A
- Anaerobic.
- Aerobic.
7
Q
What is produced during anaerobic glycolysis?
A
Lactate/Lactic acid.
8
Q
How many ATP are produced when glucose is converted to lactate?
A
2 ATP molecules.
9
Q
How many ATP are produced from glucose and 2 ATP being converted into lactic acid?
A
4 ATP total, 2 per lactic acid.
*If converted to glycogen, net of 3 ATP.
10
Q
What is produced during aerobic glycolysis?
A
Pyruvate.
11
Q
What process does glucose undergo to produce pyruvate (general)?
A
Catabolism.
12
Q
What component of the citric acid cycle is glucose converted into?
A
Acetyl-CoA.
13
Q
Where is glucose stored as glycogen?
A
- Liver.
- Muscle.
14
Q
What is the equation for aerobic glycolysis?
A
C6H12O6 + 6O2 —> 6 CO2 + 6 H2O + 38 ATP.
15
Q
What duration of exercise is fueled by stored ATP and creatine phosphate?
A
10-15 seconds.
16
Q
What duration of exercise is fueled by the anaerobic metabolism of glucose?
A
15 seconds to 2-3 minutes.
17
Q
What duration of exercise is fueled by aerobic metabolism of glucose, fatty acids, and some proteins?
A
2-3 minutes and beyond.
*Anaerobic metabolism will contribute for higher intensity spans.
18
Q
What is a triglyceride composed of?
A
A glycerol and 3 attached free fatty acids.
19
Q
Where are triglycerides found?
A
Adipose and muscle cells.
20
Q
What is the equation for B-oxidation?
A
C16H32O2 + 23O2 —> 16 CO2 + 16 H2O + 129 ATP.
21
Q
When are triglycerides primarily used?
A
Endurance exercise.
22
Q
What are 2 other energy sources the body may utilize?
A
- Volatile Fatty Acids (Ruminant and Non-Ruminant herbivores only).
- Protein.
23
Q
What are the 3 Volatile Fatty Acids (VFAs)?
A
- Acetate/Acetic acid.
- Butyrate/Butyric acid.
- Propionate/Propionic acid.
*Enter the citric acid cycle at a different point than pyruvate.
24
Under what conditions is protein utilized for energy?
1. Prolonged exercise.
2. Starvation/malnutrition.
25
How is protein utilized for energy?
AA are transported to the liver to be converted into glucose or various oxidative metabolism intermediates.
26
What % of energy in food is actually received for activity?
20-30%.
27
How is a slow rate of contraction described?
1. High heat.
2. Low efficiency.
28
How is a fast rate of contraction described?
1. Low efficiency.
2. High heat.
3. Must overcome viscous forces in ECF.
29
How is a moderate rate of contraction described?
1. Higher efficiency.
2. High heat.
3. Work being done and not trying to overcome viscosity.
30
What are the 2 types of muscle fibers?
1. Slow/Type 1.
2. Fast/Type 2.
31
What is the type of metabolism of slow twitch muscle?
Slow oxidative.
32
What color are slow twitch muscle?
Red.
33
What is the type of metabolism of fast twitch muscle Type IIa?
Fast, Oxidative, Glycolytic.
34
What is the type of metabolism of fast twitch muscle Type IIb?
Fast Glycolytic.
35
What color are both types of fast twitch muscle?
White.
36
What does the amount of each type of muscle depend upon?
1. Environment.
2. Genetics.
37
What is the relative diameter of slow-twitch muscle as compared to fast-twitch muscle?
Smaller.
38
What is the relative diameter of fast-twitch muscle as compared to slow-twitch muscle?
Larger.
39
What type of ATP synthesis does slow-twitch muscle utilize?
Aerobic.
40
What type of ATP synthesis does fast-twitch muscle utilize?
Anaerobic.
41
What is the fatigue resistance of slow-twitch muscle?
Good.
42
What is the fatigue resistance of fast-twitch muscle?
Poor.
43
What is the ATP hydrolysis rate of slow-twitch muscle?
Slow.
44
What is the ATP hydrolysis rate of fast-twitch muscle?
Fast.
45
What is the glycolysis capability of slow-twitch muscle?
Moderate
46
What is the glycolysis capability of fast-twitch muscle?
Fast.
47
What is the myoglobin content of slow-twitch muscle?
Abundant.
48
What is the myoglobin content of fast-twitch muscle?
Low.
49
What is the glycogen content of slow-twitch muscle?
Low.
50
What is the glycogen content of fast-twitch muscle?
Abundant.
51
How are the mitochondria of slow-twitch muscle described?
Abundant and large.
52
How are the mitochondria of fast-twitch muscle described?
Fewer and smaller.
53
What is the prevalence of capillaries in slow-twitch muscles?
Abundant.
54
What is the prevalence of capillaries in fast-twitch muscles?
Fewer.
55
What are the 3 types of graded muscle movement?
1. Twitch.
2. Summation.
3. Tetany.
56
What is a twitch contraction?
Brief contraction of all muscle fibers in motor unit in response to a single AP in its motor neuron.
57
What is summation?
Adding together individual twitch contraction to increase intensity of overall muscle contractions.
58
What are the 2 types of summation?
1. Multiple fiber summation.
2. Frequency summation.
59
What occurs during multiple fiber summation?
An increase in the number of motor units contracting simultaneously.
60
What is the size principle?
The smaller muscle fibers are recruited first, followed by the next largest, followed by the largest.
61
Which motor units are excited first?
The smaller ones.
62
What occurs during frequency summation?
An increase in the frequency of contraction, with twitch contractions occurring with less time between one another.
63
What happens to the muscle as frequency increases?
The new contraction will begin before the prior one is over, leading to an overlap that strengthens the second contraction. This process will repeat until tetany occurs.
64
What occurs during tetanization?
When the frequency of contraction reaches a critical level and the contractions appear to be smooth and continuous.
65
What is treppe/staircase effect?
When muscle begin to contract after a period of extended rest (ex: sleep).
66
What causes treppe?
Increased Ca2+ in the cytosol, b/c more is released from the SR with each successive muscle action potential and the failure of the SR to recapture Ca2+ ions immediately.
67
How strong is the initial contraction in treppe?
1/2 what it is 10-50 muscle twitches later.
68
What is the function of muscle sensory receptors?
Continuous feedback of sensory information from each muscle to the spinal cord to indicate the functional state of each muscle.
69
What are the 2 muscle sensory receptors?
1. Golgi tendon organ.
2. Muscle spindle.
70
What are Golgi Tendon organs associated with?
Muscle tendons.
71
What is the function of Golgi Tendon organs?
Transmit info about tendon tension and rate of change of tension.
72
What are muscle spindles associated with?
Belly of muscle.
73
What is the function of muscle spindle?
Transmit info on muscle length and rate of change of length.
74
How many intrafusal fibers are in the muscle spindle?
3-12.
75
What are intrafusal fibers attached to?
The glycocalyx of surrounding extrafusal fibers.
76
What is not found in the center of the muscle spindle?
Actin and myosin.
77
What portion of the muscle spindle contracts?
The ends.
78
What causes the muscle spindle to contract?
Excitement/stimulation by gamma motor neurons.
79
What are the 2 types of sensory endings in the muscle spindle?
1. Primary endings.
2. Secondary endings.
80
Where are primary endings found?
Encircling the central portion of each intrafusal fiber.
81
What type of fibers are primary endings?
Type 1a fiber.
82
What is the function of primary endings?
To transmit sensory signals to the spinal cord.
83
What are primary endings excited by?
Both nuclear bag and nuclear chain fibers.
84
Where are secondary endings found?
Innervating the receptor region on one or both sides of a primary ending.
85
What type of fibers are secondary endings?
Type II fibers.
86
What are secondary endings excited by?
Nuclear chain fibers.
87
What are the 2 divisions of intrafusal fibers?
1. Nuclear bag muscle fibers.
2. Nuclear chain muscle fibers.
88
What is the correlation between the number of impulses transmitted and the degree of stretching in the muscle spindle?
Positive.
89
What occurs when the length of the spindle receptor suddenly increases?
The primary ending is stimulated powerfully and excess stimulus leads to a primary response.
90
What is the simplest manifestation of muscle spindle function?
The muscle stretch reflex.
91
What occurs when the muscle is stretched suddenly?
The excitation of muscle spindles causes the reflex contraction of large skeletal muscle fibers of stretched and synergistic muscles.
92
What feedback occurs in the muscle spindle when it is stretched?
Increased spindle discharge and reflex muscle shortening cause the muscle to shorten, decreased discharge, and the muscle relaxes.
93
What is the functional significance of the muscle spindle?
Allows for the detection, response to, and control of changes in length of extrafusal fibers.
94
What is the Golgi Tendon Organ (GTO)?
An encapsulated sensory organ through which muscle tendon fibers pass.
95
How many muscle tendon fibers are connected to each GTO?
10-15.
96
When is the GTO stimulated?
When small bundles of muscle fibers are tensed by contracting.
97
What is a GTO dynamic response?
An intense response when the muscle tension suddenly increases.
98
What is a GTO static response?
Lower level, steady-state firing almost directly proportional to muscle tension.
99
What is the function of inhibitory nerve signals in GTO?
They inhibit individual muscle fibers in a negative feedback loop to prevent the development of too much muscle tension as a protective mechanism.
