spectra = bands of energy 1. electromagnetic spectrum 2. acoustic spectrum

Heat & Cold Physics Flashcards by Hannah Garrett

5 things physical therapists and patients should question

Don’t use (superficial or deep) heat to obtain clinically important long term outcomes in musculoskeletal conditions
Don’t prescribe under-dosed strength training programs for older adults. Instead, match the frequency, intensity and duration of exercise to the individual’s abilities and goals
Don’t recommend bed rest following diagnosis of acute deep vein thrombosis (DVT) after the initiation of anti-coagulation therapy unless significant medical concerns are present
Don’t use continuous passive motion machines for the postoperative management of patients following uncomplicated total knee replacement
Don’t use whirlpools for wound management

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Types of Spectra

spectra = bands of energy

electromagnetic spectrum
acoustic spectrum

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Electromagnetic Spectrum

emit energy with wavelengths & frequencies; electromagnetic radiation, radiant energy and diathermies

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Acoustic Spectrum

Subset of radiant energy, but sound vs. electromagnetic

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Acoustic energy travels at ____ velocities

lower

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Acoustic energy is more effectively transmitted through ____ tissue vs. electromagentic energy

dense

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Acoustic energy is ____ penetration vs. electromagnetic energy

deeper

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Radiant energy

process by which energy in various forms travels through space; ROYGBIV

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Radiant energy is at a _____ temperature and thus a _____ activity

higher; greater

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What are the regions of the electromagnetic spectrum?

Visible Spectrum
Invisible Spectrum
a. Infrared
b. Ultraviolet

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Infrared is located beyond the visible ____ and produces ____, which means it penetrates the skin ___

red; heat; 1cm

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Ultraviolet is located beyond the visible ____ and produces ____ changes, which means it is very _____ and only penetrates 1-2mm.

violet; chemicals; superficial

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Electromagnetic Radiations are produced when sufficiently intense ____ or ____ forces are applied to any material

electrical; chemical

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Radiant energy may be _____, _____, _____ or _____ depending upon the medium they strike (especially in tissues)

reflected, refracted, absorbed, transmitted

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Wavelength

Distance b/w peak of one wave and peak of preceding or succeeding wave

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Frequency

Number of wave oscillations occurring in 1 sec (hz)

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Velocity is equal to

Wavelength x Frequency

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Longer wavelengths produce

lower frequencies

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Shorter wavelengths produce

higher frequencies

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Radiant Modalities

purpose is to stimulate a specific body tissue to perform its normal function

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What are the various Radiant Modalities?

DULUI(th)

Diathermies (microwave/shortwave)
Infrared (cold packs, whirlpool, paraffin, moist heat)
Ultraviolet
Laser
Ultrasound

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Effects of Media (in what 4 ways can energy travel?)

Reflection
Absorption
Refraction
Penetration

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Which media produces the longest wavelengths, greatest depth regardless of frequency?

Penetration

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Reflection strikes the surface of skin and _______. It produces _____ physiological response and the ___ reflected depends upon frequency

bounces off; NO; %

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The 2 Absorption Principles/Laws

1. Arndt-Schultz Principle | 2. Law of Grotthuss-Draper

What does the Arndt-Schultz Principle state?

No reactions or changes can occur in the body tissues if the amt of energy absorbed is insufficient to stimulate the absorbing tissues

What does the Law of Grotthuss-Draper state?

Energy that is NOT absorbed will penetrate to deeper tissue layer

Refraction occurs at

tissue interfaces

Penetration has no

reflection, refraction or absorption

What are 3 additional laws related to heat & cold physics besides Draper and Arndt?

1. Cosine Law 2. Inverse Square Law 3. Bunsen Roscoe Law of Reciprocity

What does the cosine law state? What modalities is it delivered through?

- The smaller the angle b/w the energy source and 90 dg, the less reflected. This is why the sun is most intense at noon because it's almost perpendicular - The air; diathermies, UV, infrared heat

What does the inverse square law state? | hint: intensity varies inversely with the ____ of the distance from what?

Intensity varies INVERSELY with the square of the distance from the source Diathermy, radiation & UV I = 1/D^2

What does the Bunsen Roscoe Law of reciprocity state?

Intensity and duration of the dose of radiant energy are INVERSELY proportional; the pizza example Energy = Intensity x Time

What are the categories of thermal modalities?

1. Heat (thermotherapy) a. superficial b. deep 2. Cold (cryotherapy)

Local Application

requires a specific modality; specific area of treatment such as ultrasound or ice cup massage

General Application

Larger, non-specific treatment such as whirlpool, hot pack, ice pack. Helpful for dx of non-specific LBP

Local Reaction

physiological changes ocurring at the site of local application

Systemic Reaction

physiologic changes occurring in the various systems of the body such as an increase in the circulatory system

Specific Dosage

Precise treatment factors based on INJURY and TARGET TISSUES, such as E-stim

General Dosage

the effect the modality has on the patient (hotpacks, coldpacks); can't really set parameters but CAN change temperature

The 4 dosage reactions of tissues | MMVC

1. Mild 2. Moderate 3. Vigorous 4. Critical Cooling

Mild change in tissue temp provides what?

sensation benefit

Moderate change in tissue temp

TT increased to 100-105F; slight increase in blood flow

Vigorous change in tissue temp

TT increased to 106-113F (max) significant heating with marked increase in blood flow (RISK OF BURNS!)

Critical Cooling change in tissue temp

TT drops to 32-50 degrees

50 degrees F has the greatest amount of ______ and 32 degrees F has the greatest amount of _____

vasoconstriction; vasodilation

Changes in firing of thermal sensory neurons depend on (3)

1. type of receptors 2. type of stimulus (heat, cold, pain) 3. surface area

Considerations of specific dosages

1. Parameters of treatment (intensity, duration, frequency - how often) 2. Specific absorption rate of tissues

Thermal energy =

kinetic energy

Heat =

molecular motion in matter

1st law of thermodynamics states that energy cannot what?

energy CANNOT be lost, but can be transformed from one form to another

4 methods of heat transfer (RCCC)

1. Radiation 2. Conduction 3. Convection 4. Conversion

Radiation is energy transmitted from _____ to ______ source through a conducting medium

WARMER to COOLER

Conduction is

heat transfer through DIRECT CONTACT with a cold or heat source

Convection is

particles of air or water moving across tissue to create a TEMPERATURE GRADIENT

Conversion is

changing from ONE energy form into ANOTHER

What is an example of radiation?

ultraviolet light from the sun

What is an example of conduction?

A non-moving hot tub/whirlpool

What is an example of convection?

A moving hot tub/whirlpool, sprinklers during a marathon to help cool down runners

What is an example of conversion?

ultrasound, diathermy

Density is the ___ of a substance per unit ____

mass; volume

Thermal expansion is the change in _____ of a substance related to _____

density; temperature

Quantity (Q) of heat =

the amt of energy required to increase/decrease molecular motion enough to change temperature

Q = ___ x ____ x ____

S x Mass x Temp; expressed in calories; s is specific heat capacity of a substance

Specific Heat Capacity (S) is

the specific heat input required to raise the temp of 1 gram of a substance 1 degree celsius

S is influenced by (2)

1. Starting temp of substance | 2. Type of fluid intermolecular bonds

S for water

1 cal/g x Cdeg

S for paraffin wax

0.65 cal/g x Cdeg

At any given temperature, paraffin contains ___ heat than water

less

Thermal conductivity is

the ability of a particular substance to conduct heat

Conductors permit the free movement of

heat

Insulators restrict the free movement of

heat

Homeotherm is

the constant core temp largely independent of the surroundings

Core temperature

98.6 F

Shell

decreases as move distally; subcutaneous 1-2F higher than skin

Heat Loss (5)

1. Conduction (core to shell) 2. Convection (blood flow) 3. Radiation (warm body to cooler environment) 4. Evaporation (sweat & respiration) 5. Ambient Air Flow (conduction/convection due to wind flow)

Heat Gain rise of tissue temps depends on (3)

1. Ability of modality to GIVE heat to body 2. Physical properties of tissues 3. Integrity and response of body systems