PNB 2264 Lab 5: EMG Test Questions
and All Correct Answers.
EMG - Answer Electromyography
-technique used for recording the electrical activity via muscles
what are the motor unit and muscle fiber activation responsible for? - Answer supporting
and moving the muscles
motor unit - Answer -one motor neuron
-multiple muscle fibers innervated by one motor neuron
occurs when an action potential is generated by a motor neuron (all the individual muscles that
it innervates)
How is an action potential caused? - Answer due to activation of the muscle fibers
Skeletal muscles attached to bones of muscles by tendons - Answer Most skeletal muscles, as
the name suggests, are attached to bones, and their contractions are responsible for supporting
and moving the skeleton. As the figure shows, Each muscle is made up of many individual
muscle fibers organized in fascicles. Each individual muscle fiber is innervated by a branch of a
axon from a motor neuron.
-Each muscle made up of individual muscle fibers - organized in vasicuoles
-Contraction of skeletal muscles is initiated under muscles; usually under voluntary control
2 methods of recording EMG: - Answer 1)Intramuscular (IM) - insert electrodes through the
skin and into muscle
a.This Provide more insight about muscular activity (but in lab we will do surface EMG)
2)Surface EMG: place electrodes on the skin surface
, size and shape of EMG waves - Answer provide information on ability of the muscles to
respond when the nerves are stimulated
Nerve conduction study - Answer aOften EMG testing is performed with a nerve conduction
study (yields info on nerve study) help with diagnosis of nerve compression/ injury; ex: carpal
tunnel or to detect neuropathies and myopathies and many others
EMG demonstrates - Answer the action potentials of the innervated muscle fibers!
Data Acquistion test - Answer *the signal of interest must be passed through the sample
conditioning hardware for amplification, filtering, sampling, and display
-If the signal of interest, instead of being electrical, has some other functional nature (ex: blood
pressure), the temp must be converted to analog voltage by a transducer device
*Since an emg signal is already a transducer, we do NOT need to use a transducer in this lab
How is the EMG voltage monitored?
Also, signal conditioning? - Answer by the power lab (signal conditioning hardware that can
modify the signal; for ex, if too small it gets amplified / if noise contaminates the signal it gets
filtered - this process is called signal conditioning)
*AFTER signal conditioning the analog voltage is signaled
•analog - digital conversion: digitizes the signal permits the signal to be recognized by a
computer and displayed properly
analog- digital conversion - Answer digitizes the signal --> permits the signal to be recognized
by a computer and displayed properly
Hardware: Power Lab - Answer PowerLab: perform data acquisition, signal conditioning, and
pre-processing
This voltage, whose amplitude usually varies continuously over time, is monitored by the
hardware, called PowerLab, PowerLab can modify the signal, if the signal is too small it gets
amplified, if other noises contaminate the signal, signal got filtered. In general , this processes is
called 'signal conditioning'. After signal conditioning, the analog voltage is sampled at regular
intervals, a process we call it analog to digital conversion, This digitized signal now can be
recognized by a computer and displayed appropriately
and All Correct Answers.
EMG - Answer Electromyography
-technique used for recording the electrical activity via muscles
what are the motor unit and muscle fiber activation responsible for? - Answer supporting
and moving the muscles
motor unit - Answer -one motor neuron
-multiple muscle fibers innervated by one motor neuron
occurs when an action potential is generated by a motor neuron (all the individual muscles that
it innervates)
How is an action potential caused? - Answer due to activation of the muscle fibers
Skeletal muscles attached to bones of muscles by tendons - Answer Most skeletal muscles, as
the name suggests, are attached to bones, and their contractions are responsible for supporting
and moving the skeleton. As the figure shows, Each muscle is made up of many individual
muscle fibers organized in fascicles. Each individual muscle fiber is innervated by a branch of a
axon from a motor neuron.
-Each muscle made up of individual muscle fibers - organized in vasicuoles
-Contraction of skeletal muscles is initiated under muscles; usually under voluntary control
2 methods of recording EMG: - Answer 1)Intramuscular (IM) - insert electrodes through the
skin and into muscle
a.This Provide more insight about muscular activity (but in lab we will do surface EMG)
2)Surface EMG: place electrodes on the skin surface
, size and shape of EMG waves - Answer provide information on ability of the muscles to
respond when the nerves are stimulated
Nerve conduction study - Answer aOften EMG testing is performed with a nerve conduction
study (yields info on nerve study) help with diagnosis of nerve compression/ injury; ex: carpal
tunnel or to detect neuropathies and myopathies and many others
EMG demonstrates - Answer the action potentials of the innervated muscle fibers!
Data Acquistion test - Answer *the signal of interest must be passed through the sample
conditioning hardware for amplification, filtering, sampling, and display
-If the signal of interest, instead of being electrical, has some other functional nature (ex: blood
pressure), the temp must be converted to analog voltage by a transducer device
*Since an emg signal is already a transducer, we do NOT need to use a transducer in this lab
How is the EMG voltage monitored?
Also, signal conditioning? - Answer by the power lab (signal conditioning hardware that can
modify the signal; for ex, if too small it gets amplified / if noise contaminates the signal it gets
filtered - this process is called signal conditioning)
*AFTER signal conditioning the analog voltage is signaled
•analog - digital conversion: digitizes the signal permits the signal to be recognized by a
computer and displayed properly
analog- digital conversion - Answer digitizes the signal --> permits the signal to be recognized
by a computer and displayed properly
Hardware: Power Lab - Answer PowerLab: perform data acquisition, signal conditioning, and
pre-processing
This voltage, whose amplitude usually varies continuously over time, is monitored by the
hardware, called PowerLab, PowerLab can modify the signal, if the signal is too small it gets
amplified, if other noises contaminate the signal, signal got filtered. In general , this processes is
called 'signal conditioning'. After signal conditioning, the analog voltage is sampled at regular
intervals, a process we call it analog to digital conversion, This digitized signal now can be
recognized by a computer and displayed appropriately
