EMG Flashcards
a motor unit consists of _______
one motor neuron and all the muscle cells it stimulates
a whole muscle is composed of many _____
motor units
what do small motor units allow for and where can it be found
fine muscle control
hands and face
what do large motor units allow for and where can they commonly be found?
powerful but imprecise contractions
back and thighs
another name for muscle tone?
tonus
what is the function of tonus?
keep a baseline of electrical activity. keep muscles firm, healthy, and ready to respond to stimulus
motor unit summation?
(sum) increases the number of motor units being used
can get more force by using more and more motor units
temporal summation?
(tempo) makes motor units work faster
can get more force by contracting a single motor unit
describe the charges and positioning of the EMG leads.
red - positive; located laterally and approx 2-3 inches proximal from wrist
black - ground; located medially on forearm, approx 1 inch proximal from wrist
white - negative; located medially on forearm, approx 1 inch distally from nook of elbow
what two types of cells compose the neuromuscular junction?
muscle cells and nerve cells
stronger muscle tone will affect what aspect of our EMG reading?
it will affect the baseline
what makes a motor unit large instead of small?
a large motor unit will be responsible for supplying more muscle fibers
a small motor unit will control fewer, giving finer control
the stronger the contraction, the _________
more electrical activity is needed from the muscles
what does p-p stand for and what does it serve to measure?
“peak to peak”
measures difference between the maximum and minimum value within a highlighted area
