Week 3 E Stim Lecture Pt 1 Flashcards
Unit of measure that indicates the RATE OF FLOW
Ampere
What unit of measurement is current described in?
Milliampere or microampere
net movement of electrons from higher potential to lower potential
Volt vs Voltage
Volt - The electromotive force moving electrons
Voltage - force resulting from accumulation of electrons at one point in the electric circuit
What is the term describing the ease at which current flows along a medium?
What term describes resistance to flow?
Conductance
Insulator
How do you measure electrical resistance?
Ohms
What is Ohms law?
Current is directly proportional to voltage an inversly proportional to resistance
_______ is the force
______ is the flow
________ is the resistance
Volt
Amp
Ohm
Fat and skin are a _______ conductor of electricity
Poor conductor
Great insulator
Blood, nerve, and muscle are __________ conductors of electricity
Good conductors
In the body, what is the best conductor of electricity?
Blood
Does turning up the frequency of a current turn up the intensity?
No
As frequency goes up skin ______________ goes down
Skin Impedence goes
Which circuit do electrons flow in: An open circuit, or a closed circuit?
closed circuit
TENS and IFC use what kind of current?
Alternating current
T or F: Alternating current can cause chemical reactions on the skin
F because it is balanced with both positive and negative current
DC (Directional current) causes chemical reactions
Electrons always move from _______
negative to positive
Iontophoresis uses what kind of current?
DC (Directional current)
Uninterupted flow towards the postive pole
The positive electrode is called ________
the negative electrode is called ______
Anode
Cathode
HVPG and Russian stimulation uses what kind of current?
PC (Pulsatile) aka discontinuous current
What kind of current is the most stimulating for nerves and muscles?
Pulsatile current (Hi Volt and Russian)
What is the accomadation phenomenon?
A fiber that has been subjected to constant level of e-stim will become unexcitable at that intensity (amplitude)
what is the BIGGEST difference between AC and DC
DC’s ability to cause chemical changes
note: With DC these will not happen until a period of time over one minute
Skin and Fat is simular to what kind of electrical circuit?
Nerve/Blood/Connective tissue/muscle/bone is simular to what kind of electric circuit?
Series (high resistance and low current flow)
Parallel- resistors have low resistance and high current flow
T or F: The path of least resistance is usually the shortest path
F
What is frequency?
How many cycles per second: Hz
What is intensity?
The amount of stimulation, measured in amps
What is pulse duration?
How wide each wave is
Can be changed to target specific structures
Between frequency, Intensity, and Pulse Duration:
What is the main one you increase in E-Stim?
Intensity (amps)
What is capacitance?
A tissues ability to store electricity
example: if you leave e-stim on there is a heat build up
note: capacitance in tisue can be reduced by increasing frequency
What kind of tissue has the highest capacitance?
What has the lowest?
Highest: Muscle tissue
Lowest: AB nerves
Increased _____________ with decreased _______ is needed to stimulate tissues with higher capacitance AKA muscle
intensity
pulse duration
Pulse vs Cycle
Pulse applies to DC, it is the individual wave of a monophasic current
Cycle applies to AC, it is both the positive and negative wave
Increasing the amplitude of E-Stim causes what?
- Current to reach deeper tissues
- Additional nerve fibers
- Stronger muscle contraction
What does changing “Pulse Charge” do?
Determines the amount of chemicals formed
Note: for DC the pulse charge is the same as the phase charge
For AC, pulse charge is the sum of the positive and negative
Pulse Rise- the time it takes for the pulse to reach maximum amplitude
A slower pulse rise is usually more __________ compared to a faster pulse rise
More comfortable for the patient
What is duty cycle?
The time on:off within the cycles or for the total time receiving stimulation
What do these different duty cycles mean?
1:1
1:5
1:7
The first number is the time on, the second number is the time off
1:1 muscle will fatigue rapidly
1:5 less muscle fatigue
1:7 no fatigue (passive muscle exercise)
What is the definition of frequency for E-Stim?
What is the unit of measurement?
Number of impulses or cycles in 1 second
pps (pulse per second) or Hz
What kind of E-Stim is best for relieving pain?
IFC
Tetany occurs at approximately what Hz/pps
50 Hz
What does modulation mean?
Any change in the amplitude or frequency of the current
Which has the highest number of electrons? The Anode or the Cathode?
Cathode
If electrodes are placed farther apart, what happens?
The area of highest current density is deeper than if they’re placed superficial
Stimulus requires __________ in order to create an action potential and depolarization
Adequate intensity and duration
When creating chemical effects using e-stim which is more alkaline, the anode or the cathode? which is more acidic?
Cathode- Alkaline effect
Anode- Acidic effect
What is Rheobase?
What is Chronaxie?
Rheobase: The INTENSITY of current necessary to cause OBSERVABLE tissue response given a long duration
Chronaxis: The DURATION required for a current of twice the itensity of rheobase to produce tissue excitation
In order of stimulation, what is stimulated first to last:
Motor Nerves, Sharp Pain nerves, Sensory Nerves
, Dull pain nerves, Denervates muscle
First: AB(Sensory fibers)
Motor Nerves
AD Sharp Pain Nerves
C Dull Pain Nerves
Last: Denervated Muscle
Nerves always depolarize in the same order, what is that order:
Sensory
Motor
Pain
Denervated Muscles
