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Exercise Phisiology
Test 3
62
Fitness
Undergraduate 4
11/02/2009

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Term
What is muscle tissue?
Definition
Protein Storage. Movement. contractile. ATP (energy)
Term
List the functions of muscle tissue.
Definition
1. Locomotion
2. Breathing
3. Postural Support
4. Heat production
5. Venous return
Term
What is Venous Return?
Definition
sending blood back to the heart through veins via muscle contraction.
Term
List the 3 layers of connective tissue with in skeletal muscle.
Definition
1. Epimysium
2. Perimysium
3. Endomysium
Term
What is the outermost layer of connective tissue that surrounds the entire muscle?
Definition
Epimysium
Term
Which layer of connective tissue surrounds individual bundles of muscle fiber?
Definition
Perimysium
Term
What is a Fascicle?
Definition
The individual bundles of muscle fibers.
Term
What is the name for the connective tissue with in the fascicle that surrounds each muscle fiber?
Definition
Perimysium
Term
What is the Sarcolemma?
Definition
cell membrane surrounding the muscle cell.
Term
What do you call a network of membranous channels that run parallel to each myofibril?
Definition
Sarcoplasmic Reticlum
Term
What are Transverse Tubules?
Definition
membranous channels that extend inward from sarcolemma.
Term
What is in the myofibril?
Definition
many "thread like" proteins that contain contractile proteins.
Term
What is the name for thin filament?
Definition
Actin
Term
What is the name for thick filament?
Definition
Myosin
Term
Where is Troponin and Tropomyosin located?
Definition
On the thin filament (Actin)
Term
What is the function of troponin and Tropomyosin?
Definition
To regulate muscular contractions by controlling the interaction of Actin and Myosin.
Term
What is the name for the site where the motor neuron and muscle cell meet?
Definition
Neuromuscular Junction
Term
What is a motor unit?
Definition
the motor neuron and all the muscle fibers it innervates.
Term
How do nerves initiate the signal to begin muscular contraction?
Definition
by an ion difference caused by Sodium.
Term
What keeps sodium out of a muscle cell?
Definition
Protein with in the membrane closes the gate.
Term
What is resting Membrane Potential?
Definition
At rest all cells are negatively charged (unequal distribution of charged ions) The cell is polarized. The charge difference is Resting Membrane Potential. 70mV
Term
How does a muscle cell become positive?
Definition
when a stimulation of sufficient strength reaches a neuron sodium gates open and Sodium enters the cell.
Term
In a muscle cell, When is threshold reached and what happens?
Definition
when a stimulation of sufficient strength reaches a neuron sodium gates open and action potential (nerve impulse) is formed and transmitted.
Term
Explain the All-or-Nothing principal.
Definition
Once a impulse has begun the impulse will move down the entire length of the axon with out a decrease in voltage.
Term
What is the gap between the muscle and the nerve called?
Definition
Neuromuscular Junction
Term
What is the motor end plate?
Definition
pockets formed in the sarcolemma at the neuromuscular joint.
Term
Where are the Synaptic vesicles located?
Definition
On the end of the motor neuron.
Term
What is in the Synaptic Vesicles?
Definition
Acetylcholine
Term
In a muscle cell, What is released when an action potential arrives at the neuromuscular junction?
Definition
Calcium
Term
In a muscle cell, what will calcium trigger the synaptic vesicles to release into the synaptic cleft?
Definition
Acetylcholine
Term
In a muscle cell, what is the result of binding of acetylcholine the the sarcolemma?
Definition
the opening of sodium channels.
Term
What enters a muscle cell to cause depolarization and action potential?
Definition
Sodium
Term
What is the process of muscular contraction called?
Definition
Sliding Filament Theory
Term
List the 7 steps of the Sliding Filament Theory.
Definition
1. Calcium binds to Troponin
2. Myosin ATPase breaks an ATP that was on the myosin head to be 'cocked'
3. The 'cocked' myosin head binds to the actin binding site forming a cross-bridge.
4. The myosin head then pulls the thin filament this is called a power stroke.
5. In order to break the cross-bridge a new ATP needs to bind to the myosin head.
6. Relaxation occurs as calcium is pumped back into the sarcoplasmic reticlum.
7. When calcium is no longer bound to the troponin, tropomyosin once again blocks the actin binding site.
Term
How do muscle cells accomplish Relaxation?
Definition
When calcium is pumped back into the Sarcoplasmic Reticlum
Term
What is a Twitch?
Definition
A single muscle fiber contracting.
Term
What are two biochemical characteristics that determine fiber type?
Definition
1. Aerobic Capacity
2. Type of ATPase
Term
What is the relationship between energy and the amount of mitochondria in a muscle cell?
Definition
The more mitochondria a cell has, the more energy. The less mitochondria the less energy.
Term
What is the relationship between energy and the amount of capillaries?
Definition
The more capillaries, the more oxygen can be delivered. The less capillaries, the less oxygen can be delivered.
Term
How is the type of ATPase actively related to the speed of muscular contraction?
Definition
High ATPase = Fast ATP breakdown = Fast contraction
If you can use the energy quicker you on the myosin heads you can contract quicker.
Term
What are the characteristics of Slow Twitch Fibers?
Definition
More oxidative enzymes than other fibers
More capillary density
Higher concentration of myoglobin
Higher number of mitochondria.
Term
What is the name and type of Slow Twitch Fibers?
Definition
Slow Oxidative, Type I
Term
What are the characteristics of Fast Twitch Fibers?
Definition
Small number of mitochondria
Lower capillary density
Rich in Glycolitic enzymes
Myosin ATPase is higher than any other fiber= FAST
Term
What is the name and type of Fast Twitch Fibers?
Definition
Fast Glycolitic, Type II-x
Term
What are the characteristics of Intermediate muscle fibers?
Definition
They have charteristics of both fast and slow twitch fibers.
They adapt well
Term
What is the name and type of Intermediate muscle fibers?
Definition
Fast Oxidative, Type II-a
Term
How do fiber types relate to performance?
Definition
Slow Twitch - endurance
Fast Twitch - Sprinting
Intermediate - adapt
Term
What type of muscle fibers would you expect Power Athletes to have?
Definition
Type II-x (Fast Twitch)
Term
What type of muscle fibers would you expect Endurance Athletes to have?
Definition
Type I (slow twitch)
Term
What type of muscle fibers would you expect the average individual to have?
Definition
Type II-a (intermediate)
Term
How would a muscle respond to a single stimulus?
Definition
Twitch
Term
What are the 3 phases of a Twitch?
Definition
1. Latent Period (after stimulus)
2. Contraction Period (40 millisec)
3. Reaction Period (50 millisec)
Term
What do individual muscle fibers use to respond to a stimulus?
Definition
All-or-nothing response
Term
Why do fast twitch fibers contract faster than slow twitch fibers?
Definition
The Sarcoplasmic Reticlum in fast twitch fibers release calcium faster.
Fast twitch muscle fibers possess higher ATPase activity.
Term
The force of a single muscle fiber is equal to...
Definition
the number of myosin heads in contact with actin
Term
The force of a single muscle fiber depends on what 3 things?
Definition
1. Number and type of motor unit recruited
2. Initial length of the muscle
3. Nature of the neutral stimulus
Term
What is Summation?
Definition
When muscles do not have time to relax between stimulation and force being added
Term
What is Tetanus?
Definition
a combination of individual forces in a twitch.
Term
At any absolute force, velocity is greater in which muscle fiber type?
Definition
Fast twitch fibers
Term
At any absolute velocity, which type of fibers produce the greatest amount of force?
Definition
Fast Twitch Fibers
Term
At what point is greatest speed of movement generated?
Definition
At lowest workloads in both fast and slow twitch fibers.
Term
What are the two key points of the Power-Velocity Relationship?
Definition
1. Peak power generation is greater in Fast twitch (biochemical)
2. Peak power generation increases up to 200-300deg/sec
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