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70 Cards in this Set
- Front
- Back
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Where do muscle fibers come from?
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Mesoderm
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What is myogenesis?
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Formation of muscle cells
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What is primary myogenesis?
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Formation of a myotube
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What is secondary myogenesis?
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Myogenic process that leads to formation of muscle cells
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Name 2 characteristics about adult muscle fiber?
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1. Straited
2. myonuclei |
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What does the sarcoplasmic reticulum do?
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Storage cavity for protein (calcium)
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What does the epimysium do?
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Provides anatomical structure and controls shape. It covers the muscle
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What is the basic unit of muscle called?
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Sacromere
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What is the Z line?
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Where actin attaches to the sacromere
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What is the M-Line?
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Where actin and myosin overlap
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What are the 2 force producing proteins that must overlap to produce force?
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actin and myosin
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What protein acts like a spring, is very large in size and susceptible to disease?
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Titin
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Name the 3 components of thin filament?
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1: Actin
2: Troponin 3: Tropomyosin |
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How does troponin work?
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- Calcium binds to troponin
- Troponin signals tropomyosin to move out the way - Actin and Myosin Bind together resulting in force production |
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What part of the myosin does the actin bind to?
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Head of myosin
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Connective Tissue and muscle are linked to this protein?
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Dystrophin
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What is dystropin?
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Primary connection between actin and muscle cell membrane
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What is the main problem caused with Duchennes Muscular Dystrophy?
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Dystrophin protein is not made due to mutation
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How do boys with Duchenne's deal with injury?
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Satellite cells
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What are stored in the myonuclei?
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Proteins
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What types of cells work to repair the muscle after damage or insult?
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Satellite Cells
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Where do the muscle and muscle fibers interact?
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Neuromuscular Junction
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What chemical is released via a neuromuscular transmitter at the NMJ?
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Ach (Acetylcholine)
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Too many lipid droplets in muscle can contribute to what disorders?
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Insulin resistance and diabetes
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What are the 3 things that regulate force production?
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1. Motor Neuron
2. Mechanical Properties 3. Cellular properties |
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How does the nervous system effect force production?
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Recruitment and Frequency
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The number of fibers controlled by a neuron is called what?
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innervation ratio
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Motor units are recruited according to the size principle. What is the size principle?
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- Small motor units (fewer muscle fibers) have a small motor neuron and a low threshold
- big motor units (more muscle fibers) have a big motor neuron and a high threshold |
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Where does communication take place between the nerve and the muscle?
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Synaptic Cleft
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Action Potential is regulated by what?
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Ions
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What is length tension?
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Refers to the optimal length you use to produce force
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Action potential works to increase what?
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surface area of the muscle fiber
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What does the Sarcoplasmic Reticiulum store?
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Calcium
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What 2 proteins link up to signal to release of calcium?
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DHPR and RyR
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Aging has a dramatic effect on what?
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Force Production
-Ability to produce force - rate of producing force |
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How does myosin ATPase affect force?
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Effects of rate of ratcheting movement
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What must attach to actin and myosin for them to be able to break their bond?
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ATP
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As activity level increases, what happens to power production?
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Increases
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What is muscle fatigue?
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A failure to produce a desired or expected force output
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What 3 changes do you see with fatigue?
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1. decrease in force production
2. slower contraction time 3. slower relaxation time |
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What is the central fatigue hypothesis?
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The buildup of serotonin induces drowsiness which contributes to fatigue
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What is Tryptophan and what happens to it with strenuous exercise?
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Its a precursor to serotonin which during strenuous exercise increases.
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What are the 3 places muscle fatigue initates from?
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1. Neuromuscular transmission
2. Motor Neuron excitability 3. Sarcolemma excitability |
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During repeated contractions, what happens to calcium release?
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Channel becomes dysfunction and causes a decrease in force production
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What substance allows channels to open back up?
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Caffeine, it restores calcium levels and increases force production
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When the SR shuts down, what 2 proteins become dysfunctional?
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DHPR (RyR) and ATPase
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What are the 2 major duties of the SR that fail during repeated contraction?
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1. Uptake of calcium
2. Release of calcium |
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During repeated contraction, actin and myosin are not responding to signal and as a result, what happens to force production and sensitivity?
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Both decrease
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As muscle gets depleted of glucose, what happens to force production?
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decreases
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in frog muscle, with repetitive contraction what happens to force production, lactate, ATP, Pcr?
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ATP doesnt change
Lactate increases force production decreases Pcr decreases |
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What are the advantages of being oxidative?
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- A lot of mitochondria (lacks contractile proteins)
- good for endurance athletes |
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What are the advantages of being glycolytic?
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- A lot of contractile proteins
- Produce more power - good for power athletes |
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What are the most powerful and fast fibers?
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Type II
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Histiochemistry is used to determine fiber type. What enzyme are you staining for in this procedure?
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Myosin ATPase
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Immunochemistry can be used to determine what?
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MHC isoforms
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During 2 months of endurance training, what happens to SDH and glycogen levelss?
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Both increase
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What are the energy requirements for maintanance of Type I and Type II fibers?
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Type II requires little energy
Type I requires a lof of energy |
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What is muscle hypertrophy?
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An increase in muscle cell size
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What is muscle atrophy?
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wasting of muscle tissue
- any loss in muscle size |
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Muscle hypertrophy is dependent on what 3 things?
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1. increase in muscle mass
2 increase in muscle CSA 3 increase in force production |
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Muscle quality accounts for what 2 things?
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Muscle size
force production |
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what are 2 critical aspects that affect muscle size?
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satellite cell proliferation
protein synthesis |
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What happens to muscle fiber size with training and de-training?
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Training: Increases
De-training: Decreases |
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With aging, what happens to muscle fiber size and muscle mass?
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Both decrease
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After a bout of exercise what happens to the rate of protein synthesis?
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Increases
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During exercise what happens to protein content and protein concentration? Protein degradation?
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-it increases because muscle size increases
- muscle concentration remains constant -protein degradation rates increases |
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After a bout of exercise what happens to satellite cells, protein synthesis, protein degradation ?
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-satellite cells: increases proliferation
-protein synthesis: increases and remains elevated for ~24hours - protein degration: increases for short period of time |
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What is the formula for total protein?
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Total Protein= Protein synthesis- Protein degradation
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What happens to the rates of protein degradation with reduced mechancial load?
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increase
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Changes in muscle size are regulated by what 3 things?
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Satellite Cells
Protein Synthesis Protein Degradation |
