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The cytoplasm of a muscle fiber is also called
Sarcoplasm
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A muscle fiber membrane is also called
sarcolemma
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Smooth endoplasmic reticulum of muscle fiber is also called
Sarcoplasmic reticulum
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Mitochondria in the muscle cell can be called
Sarcosomes
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Almost all the muscles are dervied from
Mesoderm
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What is the one muscle exeption not having its derivative from mesoderm
Dilator Pupillae m. (comes from neuroectoderm)
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Voluntary motion is innervated by
Somatic motor neurons
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Syncytium is
The fusion of many small cells, containing hundreds of nuclei within one cell or fiber
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In muscle the syncycium is the fusion of many precursur cells called
Myoblasts
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The strength of a cell fiber depends on its
Diameter
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What substances are found in abundance in muscle cells
- Contractile proteins
- Mitochondria (energy)
- Glycogen (glucose)
- Myoglobin (oxygen)
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Each muscle cell is surrounded by
External Lamina
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Satelilite cells are found where in the muscle and perform what function
They are muscle precursur cells and can be found in the basal lamina beneath the external lamina
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What are the three types of muscle fibers
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What are the qualities of the red muscle
They are slow to react, but have stamina, they are small in diameter and have a lot of myoglobin (why its red) and mitochondria, they use Oxidative phosphorilation
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What are the qualitites of white muscle
They are fast but easily fatigued, have a large diameter, poor in myoglobin (why it is white), little mitochondria, use Glycolysis and Creatine Phosphate
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What are the qualities of intermediate muscle
It is simply a mixture of the other two in differing amounts of each type
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What is the structure of a muscle from the largest unit to the smallest
- Muscle
- Fascicle
- Fibers (muscle cell)
- Myofibrils
- Myofilaments (Actin and myosin)
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Myofilaments contain
Contractile proteins (actin and myosin)
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The coverings of muscle are
- Epimysium (around muscle)
- Perimysium (around bundle)
- Endomysium (around muscle fiber)
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Epimysium is made up of
Dense irregular connective tissue
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Perimysium which covers a bundle is made up of
Connective tissue
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Endomysium which covers muscle fibers is made up of
Loose connective tissue
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The contractile element of muscle is
Myofibrils
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Myofibrils are made up of
Myosin (thick) and Actin (thin) filaments
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What creates the striations in muscle
Alternating zones of thick and thin filaments
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Desmin does what
It holds the myofibrils in register with each other
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The thin filament is made up of
F-actin, a polymer formed from globular actin molecules (G-actin)
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The thick filament is made up of
200-300 myosin II molecules aggregated in a parallel but staggered array.
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Nebulin is
Facilitates the attachment of the thin (actin) filament to the Z line
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Tiltin is
What attaches the thick filament (myosin) to the Z line. It also prevents over stretching
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Tropomyosin
Along with troponins, mask the myosin binding site on the actin molecule.
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During contraction, Ca++ binds to the
Troponin C (TnC), and tropomyosin shifts exposing the myosin binding sties
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Where is the positive end of the sarcomere
It is located at the Z line, the negative end is at the apex of the actin
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What are the accessory proteins that maintain precise alignment of the thick and thin filaments
- Nebulin
- Titin
- C protein (both sides of myomesin)
- myomesin (make m line)
- alpha actinin (make the z line)
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Papain is a meat softner that
Breaks the myosin head off
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C protein and Myomesin are
Myosin binding proteins
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What make up the Z line
Alpha actin, an actin binding protein
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Creatine Kinase is
Present at the M-Line and helps provide the supply of ATP from ADP
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Dystrophin
Connects the thin filament (actin) to the cell membrane allowing the force generated to get beyond just the filament
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What does the sarcoplasmic reticulum, and terminal cisterna do?
They store the Ca ions
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The triad is located at
The A-I junction
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The T tubules
Connecting tubes to the sarcoplasmic reticulum and Terminal Cisterna (all are connected)
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Muscle to nerve junctions are called
Myoneural junctions
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A large motor unit moves
In a big group but doesn't provide fine movements
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A small motor unit
Does precise work in small bundles
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A schwann cell on a neuromuscular junction will only
Cover the neuron with one layer
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During contraction thin filaments
Slide toward the M band
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During contraction the lengths of the individual myofilaments
Do not change, but the Z lines are brought closer together
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The different bands do what during contraction
- The M and A bands remain the same length
- The I and H bands diminish in length
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Without ATP a muscle would
Stay contracted
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The sarcoplasmic reticulum has what functions
It stores Ca, and has voltage gated Ca release channels
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Each Triad contains
Two cisternae and one T tubule
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What provides additional surface area at the synaptic cleft
Junctional folds
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The regeneration of muscles can happen if
The external lamina and satellite cells are intact
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What is Huxleys theory
During contraction, the lengths of the individual myofilaments don't change, but the Z lines are drawn closer together
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What causes rigor mortis
The lack of ATP, keeping the muscles contracted
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Botulism
Toxin produced from Clostridium Botulinum and interferes with the release of acetylcholine leading to muscle paralysis. This happens rapidly
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Mysthenia Gravis
Autoimmune disease, characterized by muscle weakness. Autoantibodies attach to acetylcholline receptors. This takes time to take effect
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Muscle spindles function when
The muscle is stretched, they are sensory receptors, located near the tendon
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Intrafusal muscle fibers are skeletal muscle fibers that
Make up the muscle spindle and detect the rate and change in length of muscle. They give us a sense of where our muscles are. These are considered the modified group
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Extrafusal muscle fibers are considered
The regular type
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What is the receptor in muscle that the action potentional triggers
DiHydroPyridine
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DHP tugs at what, releasing Calcium into the sarcoplasmic reticulum
Ryandine receptor
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How does calcium in the sarcomere create a contraction of muscle
It binds to the troponin C opening the actin binding site for myosine to contract the muscle
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How is myosin cocked for contraction
ATP binds to it, putting it into a ready state
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What is troponin made up of
It has an actin binding unit, a calcium binding unit, and an tropomyosin binding unit.
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What is a crossbridge
It is the myosin head
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What energizes the cross bridge
Hydrolysis of ATP
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The A band is specifically the
Thick filament or myosin
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The movement of Ca+ back into the sarcoplasmic reticulum is done by
The primary active transport of ATPase SERCA pump
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Each myosin molecule has how many heads
Two
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The A band contains
The section where the myosin and actin overlap
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Troponin is a regulatory protein that permits
The binding of the myosin to actin when Ca is present
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What is the difference between the troponin C, T and I
- C is where the calcium attaches
- T is where the the troponin attaches to the tropmyosin
- I is where the inhibition of actin and myosin happens
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Tetanic contraction (tetany) is when
An isometric contraction is produced by multiple stimuli
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The DHP (DihydroPyridine) receptor is found where
In the T tubule where it receives the action potential
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What part of the SR contacts the T tubule
The terminal cisternae
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Where is the Ryandine receptor located
On the surface of the SR
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What is an Isometric contraction compared to an isotonic contraction
- Isometric creates force but no movement (like holding an apple)
- Isotonic either shortens or extends the muscle
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Concentric does what as opposed to Eccentric
- Concentric, Muscle shortens, (Flexes)
- Eccentric, Muscle lengthens, (Extends)
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A single action potential theoretically causes a
Twitch
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Multiple twitches add up to a
Isometric contraction
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Passive tension is caused from
Stretching
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A muscle unit consist of
Muscle fibers of only one type
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One motor neuron can trigger
Many muscle fibers of only one fiber type
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If you have a slow twitch on a muscle you know that it is
A slow twitch oxidative fiber (Red)
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If you have a fast twitch what fiber type could it be
- Fast twitch Oxidative-Glycolitic Fiber (Intermediate)
- Fast twitch Glycolitic fiber (White)
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W fast twitch muscle uses what for ATP production
- Creatine phosphate
- Glycolysis
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A slow twitch Oxidative fiber uses what for energy
Oxidative Phosphorilation
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All Oxidative Phosphorilation muscles are high in
Myoglobin (Red fibers)
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What factors determine the ability of a muscle to create strong tension
- AP frequency
- Fiber length
- FIber diameter
- Amount of fibers
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In what order are the motor fibers recruited
- Slow Ox (smallest)
- Fast Ox-Gly (medium)
- Fast Gly (large)
Red-Intermediate-White
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What are the three ways documented that muscle fatigues
- Conduction failure at T tubule (High K+ or Na +)
- Cross bridge cycle inhibition (High ADP and Pi)
- Increase acidity
- Glycogen depletion
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What are the three ways to create ATP for muscle
- Creatine Phosphate (fast 1 ATP)
- Glycolysis (intermediate 2 ATP)
- Oxidative phosphorilation (slow 32 ATP)
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