- Shuffle
Toggle OnToggle Off
- Alphabetize
Toggle OnToggle Off
- Front First
Toggle OnToggle Off
- Both Sides
Toggle OnToggle Off
Front
How to study your flashcards.
Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key
Up/Down arrow keys: Flip the card between the front and back.down keyup key
H key: Show hint (3rd side).h key
PLAY BUTTON
PLAY BUTTON
13 Cards in this Set
- Front
- Back
|
What is an EMG?
|
electromyogram
an external recording of the electrical activity of muscle Gives information on the speed of electrical conduction through the cardiac conduction system used to diagnose abnormalities and disease of the heart, measures electrical activity of muscles at rest and during contraction |
|
When stimulated by a motor neuron, a skeletal muscle fiber forms _______ that activate contraction of the fiber.
|
action potentials
|
|
The EMG records the combined action potential signals produced by _____ of activated muscle fibers
|
several
|
|
Define motor unit
|
motor neuron & all muscle fibers it supplies (4 to 1000’s)
• when motor neuron fires (action potential) all muscle fibers it innervates contract |
|
Define motor unit recruitment
|
an increase in # of active motor units
• ↑ motor unit recruiment = ↑ force of contraction |
|
Define antagonistic muscles
|
muscles that work in opposing directions
|
|
Define fatigue
|
muscle is physiologically unable to contract
|
|
Increasing the force of muscle contraction is accomplished by _____ recruitment of motor units, which increases the number of muscle fibers activated in the muscle.
|
increasing
|
|
The more muscle fibers that are stimulated to produce action potentials, the _____ the EMG signal will be
|
stronger
|
|
Explain how your results from Part A demonstrate recruitment of motor units.
|
Part A demonstrates recruitment of a motor unit because the amount of action potentials increases with the increase in the amount of weight being lifted. The body produces more action potentials when more energy effort is used.
|
|
Explain how your results from Part B demonstrate fatigue of the muscle
|
Part B shows that as the muscle fatigues more and more motor units got used.
|
|
What is meant by the term antagonistic muscles?
|
Antagonistic muscles are opposing muscle pairs
|
|
Summarize your results from Part C and explain briefly what the results demonstrate about the control of antagonistic muscles by the CNS.
|
In Part C the control of antagonistic skeletal muscles are complete opposites while in flexion the biceps produce a larger amount of ATP. The triceps keeps a small constant amount of ATP. During extension, the triceps had a very large amount of ATP being produced while the biceps had a moderate amount at the beginning but subsided.
|
