Term
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Definition
| a single motor neuron and all of the muscle fibers that it supplies |
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Term
|
Definition
| a response to a single threshold stimulus |
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Term
| What is the threshold stimulus? |
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Definition
| a stimulus that is just large enough to generate and action potential across the sarcolemma |
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Term
| What are the three phases of a muscle twitch? |
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Definition
1. latency
2. contraction
3. relaxation |
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Term
| What is the latency phase of a muscle twitch? |
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Definition
| it is the period between the stimulus and the initiation of the muscle twitch response |
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Term
| What happens in the contraction phase of a muscle twitch? |
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Definition
| the power stroke occurs; the onset of shortening to peak of tension development |
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Term
| What happens in the relaxation phase of a muscle twitch? |
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Definition
| Ca2+ is taken back up into the terminal cisternae and the cross bridges let go |
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Term
| Is twitch duration the same throughout the entire body? |
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Definition
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|
Term
| Which has a faster twitch, postural or other muscles? |
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Definition
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Term
| Why do postural muscles have a slower twitch than other muscles? |
|
Definition
| these muscles are designed to keep you upright and stabilize joints, they don't really need to contract quickly |
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Term
| Why do other muscles (ex. eye muscles) have a faster twitch than postural muscles? |
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Definition
| these muscles need to respond to stimuli very quickly |
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Term
| What does a graded muscle response do? |
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Definition
|
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Term
| What are the different types of graded muscle response? |
|
Definition
-temporal summation
-tetany summation
-multiple motor unit summation
-treppe effect |
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Term
| What happens in temporal summation? |
|
Definition
| the rate of stimulus delivery is increased |
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|
Term
What type of graded muscle response is this?
[image] |
|
Definition
temporal summation
[image] |
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Term
| What happens in tetany summation? |
|
Definition
| there is no relaxation in the muscle whatsoever (Charlie horse) |
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|
Term
What type of graded muscle response is this?
[image] |
|
Definition
|
|
Term
| What happens during multiple motor unit summation? |
|
Definition
| more motor units are recruited as stimulus intensity increases; end result is smooth steady increase in force generated |
|
|
Term
What type of graded muscle response is this?
[image] |
|
Definition
multiple motor unit summation
[image] |
|
|
Term
| Which motor units are usually recruited first in multiple motor unit summation? |
|
Definition
| smallest followed by larger ones |
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Term
| What happens in the treppe effect? |
|
Definition
| repeated stimuli causes the muscles to "warm up" causing an increase in temperature, therefore making enzymes more efficient and giving a stronger contraction |
|
|
Term
What type of graded muscle response is this?
[image] |
|
Definition
|
|
Term
| What are the three types of muscle contraction? |
|
Definition
-isotonic
-isometric
-isokinetic |
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Term
| What is a contraction defined as? |
|
Definition
| the force generated by crossbridge formation |
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Term
| What is tension defined as? |
|
Definition
|
|
Term
|
Definition
|
|
Term
| What is an isotonic contraction? |
|
Definition
| tension stays the same but the length of the muscle changes |
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|
Term
| What are the two types of isotonic contraction? |
|
Definition
|
|
Term
| What is a concentric isotonic contraction? |
|
Definition
| contractions that shorten the muscle |
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Term
| What is an eccentric isotonic contraction? |
|
Definition
| contractions that lengthen the muscle |
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Term
| What is the only type of contraction that is explained by Huxley's Theory? |
|
Definition
| concentric isotonic contraction |
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|
Term
| What is an isometric contraction? |
|
Definition
| the muscle stays the same length but the force changes |
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|
Term
| What is an example of an isometric contraction? |
|
Definition
|
|
Term
| What is an isokinetic contraction? |
|
Definition
| contraction performed at the same speed with a controlled angular velocity of joint; usually mechanically induced |
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Term
| What are the factors the determine the force of contraction? |
|
Definition
-number of fibers and stimuli
-size of muscle
-elastic elements
-tension
-muscle length |
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Term
| How does the number of fibers and stimuli influence the force of contraction? |
|
Definition
| temporal summation and recruitment of fibers |
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|
Term
| How does the size of the muscle influence the force of contraction? |
|
Definition
| the larger the muscle, the larger the force generated |
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Term
| What are the non-contractile elements of the muscle cell? |
|
Definition
-connective tissue covering of muscle cells
-tendons
-organelles
-sarcolemma |
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|
Term
| What are the supporting proteins of the muscle cell? |
|
Definition
|
|
Term
| How does tension influence the force of contraction? |
|
Definition
| sometimes it is necessary in order to overcome the elasticity of non-contractile elements |
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|
Term
| What is internal tension? |
|
Definition
| tension directed at overcoming non-contractile element elasticity |
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|
Term
| What is external tension? |
|
Definition
| tension directed to overcome the actual load |
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Term
| How does muscle length influence the force of contraction? |
|
Definition
| length-tension relationship; needs the perfect length |
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|
Term
| What happens if there if too much overlap of the thin and thick filaments? |
|
Definition
| there will not be enough room to pull, thereby resulting in a 75% contraction |
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|
Term
| What happens if there is too little overlap of the thin and thick filaments? |
|
Definition
| it is almost impossible for cross bridges to form thereby resulting in 170% contraction (overstretched) |
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|
Term
| What happens if the thin and thick filaments are at resting length? |
|
Definition
| there is not too much or too little overlap and there is 100% contraction |
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|
Term
| How are velocity and duration of contraction related? |
|
Definition
| the amount of force that can be generated is directly related to velocity of action and duration of it |
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|
Term
| What happens to the duration when load is increased? |
|
Definition
| the greater the load, the less the muscle shorten and the shorter the duration of contraction |
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Term
| What are the characteristics of slow oxidative fiber type? |
|
Definition
| myosin ATPase is relatively slow; lots of myoglobin; many capillaries; lots of mitochondria; dependent on oxygen; low glycogen stores; good for endurance exercise |
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|
Term
| What are the characteristics of fast glycoytic fiber type? |
|
Definition
| fast ATPase; less myoglobins; not dependent on oxygen; high glycogen storage; good for low endurance exercise |
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|
Term
| What are the characteristics of fast oxidative glycolytic fiber type? |
|
Definition
| fast ATPase; some glycogen stores; some dependence on oxygen; little endurance exercise |
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