Chapter 3: Energy Flashcards
1
Q
Electrophysical Agent
A
- for of therapy used in rehabilitation that changes tissue through water, temp, sound, electricity. Include TENS, ultrasound, whirlpool, hot and cold packs, and other modalities
- alternate: application or removal of energy from biological tissue in order to stimulate that tissue to perform its normal function
2
Q
TENS
A
transcutaneous electrical nerve stimulation
3
Q
energy
A
- capacity to do work. manifested as motion (kinetic), potential (potential energy), light, heat, ionizing radiation, sound
- neither created nor destroyed
4
Q
radiant energy
A
- process by which energy of various forms travels through space
- everything above absolute zero (-273C) emit radiant energy
- occurs when sufficient electrical or chemical force is applied to an object
- explained by quantum and electromagnetic wave theory
5
Q
radiant energy cont.
A
- thought of as a packet of energy carried along by propagating waves
- constant velocity (3x10^8 m/sec)
- includes radio waves, microwaves, infrared waves, visible light waves, ultraviolet waves, x-rays, gamma rays, and cosmic rays
6
Q
quantum theory
A
- packet of energy (indivisible)-photon
- produced by high velocity electronic or molecular motion or transformed kinetic energy released when molecules collide
- E(quantum)=H(Planck’s constant) x f(frequency)
- the higher the frequency, the higher the photon energy-> potentially destructive
7
Q
electromagnetic wave theory
A
- energy is transmitted by oscillatory motion in the form of electromagnetic waves
- composed of perpendicularly oriented fields of electric and magnetic composition that vary over time
- can propagate without the need of a medium (travel through vacuum, like space)
- velocity=wavelengthxfrequency(f)
- shorter the wavelength, the higher the frequency
8
Q
radiant energy cont.
A
- quantum theory states that if frequency (f) is low, energy (E) must be low
- electromagnetic theory states that if frequency (f) is low, wavelength is long (high)
- thus, therapeutic modalities at low electromagnetic frequencies have relatively long wavelengths and low amounts of energy, safe to apply to human system
9
Q
low frequency electromagnetic radiation
A
- ELF waves
- shortwaves
- microwaves
- IR radiation
- visible light
- ultraviolet A and B radiation
- all non-ionizing (cannot break molecular bonds or produce ions)
10
Q
high frequency EMR
A
- x-rays
- gamma rays
- are ionizing (can inhibit cell division, break molecular bonds and form ions)
11
Q
arndt-schultz principle
A
- energy absorbed must be sufficient so as to stimulate the absorbing tissues
- -ex: e-stim for muscle contraction. the current intensity must be strong enough to facilitate depolarization of the nerve
- -ex: heat to increase tissue elongation. must be intense enough to increase viscoelastic properties of tissue
- too much energy absorbed may impair normal function of the tissues
12
Q
law of Grotthus-Draper
A
- if energy is not absorbed by the superficial tissue, then it will penetrate to deeper tisues
- ex: 1MHz, US will be more efficient in treating deeper tissues than 3 MHz, US
13
Q
cosine law
A
- maximum amount of absorption of radiant energy occurs when the source is at righ angles to the absorbing surface
- energy absorbed=energy available x cos theta
14
Q
inverse square law
A
-intensity of the radiation striking the surface varies inversely with the square of the distance from the source
15
Q
bunsen roscoe law of reciprocity
A
- intensity and duration of the dose of radiant energy are inversely proportional
- energy (E)=intensity (I) x Time (T)
