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PA: Heat
Question | Answer |
---|---|
What is heat used for? | Pain relief Promote relaxation Increase blood flow Facilitate tissue healing Decrease muscle spasm Prepare stiff joints for exercise |
What two types of heat are there? | Superficial and deep |
How far down does superficial heat reach? | 1-3 cm |
What are examples of superficial heating? | Heat pads Paraffin WWP |
What does superficial heating reach? | Mostly skin Some subcutaneous and muscle |
How far down does deep heat reach? | Up to 5 cm |
What are examples of deep heating? | Continuous US Diathermy |
What does deep heating reach? | Muscle belly Deeper portions of joint capsule |
What happens to the metabolic rate with heat? | Increases 2-3 times for each 10 degree C of an increase in temperature |
What 3 factors influence the vasodilation of heat-exposed skin? | Axon reflex Release of chemical mediators Local SC reflex |
What do the changes in the body due to heat depend upon? | How much the temp increases Rate of increase Volume of tissue exposed Tissue composition Capacity of tissue to dissipate heat |
What is the therapeutic level of heating for tissues? | Tissue must be increased to between 40 and 45 degree C |
What are the vascular responses to heat? | Vasodilation |
What is the change in temperature of skin determined by? | Sympathetic nervous system |
What is the change in temperature of skeletal muscle determined by? | Metabolic control |
How does axonal reflex energy dispersal work? | Cutaneous thermoreceptors are stimulated Impulses are sent to SC from cutaneous receptors and toward skin blood vessels A vasoactive mediator is released |
How does chemical mediator energy dispersal work? | Heat produced mild inflammation due to the chemical mediators that are released |
What chemical mediators are released with heat? | Histamine and prostaglandins |
What are histamines and prostaglandins responsible for? | Vasodilation |
What does sweat sweat secretion (due to temperature elevation) release? | Enzymes that release bradykinin |
What does increased capillary permeability allow? | Fluid to leak out into the interstitial space (edema) |
What does the spinal reflex do? | Cutaneous nerves send signals to spine SC sends signals to decrease symapthetic activity |
What does the decrease in sympathetic activity allow blood vessels to do? | Relax (vasodilation) |
What type of heat does muscle have the greatest response to? | Exercise |
What happens to the blood in the skin with vigorous exercise? | It's shunted away |
What is heat used for in terms of neuromuscular response? | Analgesia and spasms |
What are the neuromuscular responses to heat? | Alters nerve conduction velocity |
What is the pain-spasm-pain cycle? | Have pain - go into spasm - have more pain - go into more spasm |
Are modalities liely to increase temps enough to affect type II or Ib afferents? | No |
How does a MHP decrease spasm if it can't increase the temp enough to be effective? | Heats up skin Decrease in gamma efferent which doesn't stretch spindle as much Then you start reducing afferent activity This results in motor neuron decreasing firing and decreasing spasms |
What effects does heat have on strength and endurance? | It will decrease some during the first 30 minutes after heating ends and will gradually increase over the next two hours |
What effects does heat have in connective tissue? | Can alter viscoelastic properties |
What do viscous properties allow? | Connective tissue to be elongated after stretch released |
What do elastic properties allow? | Tissues to return to pre-stretch state |
What three techniques are used to stretch connective tissue? | Constant load Rapid stretch Constant rate of stretching |
How long should collagen (IT band) be stretched to really see effects? | 2-4 hours |