Question

Electromyography is the recording of electrical activity of a muscle at rest and during a contraction. Select the best statement below regarding EMG.

Select one:
A. When an action potential occurs in a motor neuron, all the attached muscle fibres contract
B. The medical instrument that measures EMG is called an electromyograph
C. The record that the EMG produces is called an electromyogram
D. An EMG is used to investigate problems

Answer 1

The correct statement about EMG is that the record it produces is called an electromyogram. EMG measures the electrical activity in muscles during rest and contraction, much like an ECG records cardiac muscle electrical impulses.

Step-by-step explanation:

Electromyography (EMG) is a technique for evaluating and recording the electrical activity produced by skeletal muscles. The correct statement regarding EMG is C. The record that the EMG produces is called an electromyogram. An EMG is similar to an electrocardiogram (ECG), which records the electrical impulses of the cardiac muscle. In the context of EMG, when a motor neuron stimulates muscle fibers at the neuromuscular junction, acetylcholine is released, initiating a muscle action potential. This leads to muscle contraction, which can be recorded by an EMG. However, a single twitch, caused by one action potential, generally does not produce significant muscle activity. It is the frequency of action potentials and the number of motor neurons sending these impulses that generate a stronger and more sustained muscle contraction, known as a graded muscle response.