Physiological effects of modalities

Question 1

what are the biophysical principles of tissue cooling?

Answer 1

1. arteriolar vasoconstriction
2. decrease in metabolism and redue inflammation
3. elevated pain threshold: affecst rate of pain transmission

Question 2

What are the biophysical principles of tissue heating?

Answer 2

1. metabolic changes
2. hemodynamic chnages
3. neural chnages
4. skeletal muscle changes
5. collagen tissue changes

Question 3

What are the parameters of Ultrasound

Answer 3

1. intensity W/cm2
2. frequency MHZ: frequency of the sound waves (rapid/short or slow/long)
   - the longer the wave the deeper the sound waves go = a lower frequency
   - dense tissue like bone absorbs more and heats up the tissue.
3. mode: continuous vs pulse (continusous has a 100% duty cycle which is the time spent on)

Question 4

What are the effects of ultrasound

Answer 4

thermal:
nonthermal

Question 5

What is thermal ultrasound tissue heating affected by

Answer 5

increased tissue temperature affected by:
-absorption coefficient/tissue type (more rapid in dense tissue)
-intensity
-frequency

Question 6

non thermal effects of ultrasound

Answer 6

-cavitation, microstreaming, acoustic streaming
-increased intracellular calcium
-promotes cell function
-pulse (20% duty cycle): heat disperses during off cycle
-increase skin and cell membrane permeability
-increase mast cell degranulation
-promotes macrophage response
-stimulate proteoglycan synthesis by chondrocytes
-increase NO causing vasodilation and increase blood flow

Question 7

effects of frequency on thermal effects of US?

Answer 7

-shorter frequency penetrates deeper tissues (1 mHZ up to 6cm)
-higher frequency stays superficial (3 MHz up to 2.5 cm) and heat sup faster

Question 8

Effects of cold

Answer 8

• causes decreases in bradykinins and histamine = decreased vasodilation
• increase smooth muscle tone = increased vasoconstriction
• vasoconstriction = reduced blood flow
• increase blood viscosity = reduced blood flow
• elevated pain threshold by reducing the nerve conduction, and disinhibits muscle inhibition that occurs at an injured joint

Question 9

Effects of heat:

Answer 9

• vasodilation = increased blood, tissue healing and relief of pain
• fluid viscosity decreases = increased blood flow, tissue healing and relief of pain
• increased metabolism/cellular activity = increased tissue healing and relief of pain
• increased collagen extensibility = soften scares and decreases stiffness = relief of pain
• nerve stimulation = relief of pain

Question 10

Thermal effects of ultrasound

Answer 10

same effects as heat
- vasodilation = increased blood, tissue healing and relief of pain
- fluid viscosity decreases = increased blood flow, tissue healing and relief of pain
- increased metabolism/cellular activity = increased tissue healing and relief of pain
- increased collagen extensibility = soften scares and decreases stiffness = relief of pain
- nerve stimulation = relief of pain

Question 11

effects of e-stim

Answer 11

• muscle contraction
• pain control
• tissue healing
• Transdermal drug delivery via iontophoresis
• Stimulate AP in nerves
• Direct muscle depolarization (need more stimulation due to the muscle having a higher resting membrane potential)
• Ionic effects
• Strength duration curve: