LECTURE 2 Flashcards
5 mechanisms of delivering heat?
Conduction, convection, radiation, conversion, and evaporation
Definition of convection heating
transference of heat to a body by the movement of air, matter, or liquid around or past the body. E.g., Whirlpool (hot or cool)
What part of the brain gets signalled from hot and cold receptors, initiating shivering or sweating?
hypothalamus
2 examples of deep heating:
short wave Diathermy and ultrasound shock wave
How deep do deep heating modalities penetrate
3-5 cm
What is vigorous heating temp?
40-45 degrees C
Temperature of the hydrocollator?
71-79 degrees C
How does heat decrease pain and spasm?
It closes the “gate” that sends pain signals to the cerebral cortex A beta, increase firing of GTO, and decrease firing of muscle spindle
Contraindications for heat and ice?
Open wounds, compromised circulation, anesthetic skin, application to eyes or genitals, application onto the abdomen during pregnancy
Signs of cold sensitivities?
hives, drop in BP, facial flushing, an increase in HR and syncope
Why heat vs cold?
heat- used chronically, is preferred as it soothes pain. Cold can reduce swelling and redness
Name of proteins that are created under heat (or cold stress) and act as chaperones to make sure the other proteins are unfolded correctly
Heat shock proteins
Temperature Regulation strategies:
shivering or sweating
Conduction:
heat loss or gain through direct contact between materials with different temps. E.g., Heat absorbed by body when using a hot pack
Convection:
transference of heat to a body by the movement of air, matter, or liquid around or past the body. E.g., Whirlpool (hot or cool)
Radiation:
transfer of heat from a warmer source to a cooler source. E.g. A heat lamp
Conversion:
temp change that results when energy is transformed from one form to another. E.g., Ultrasound (mechanical energy to thermal energy)
Evaporation:
transformation from a liquid to a gas. This requires an energy exchange. E.g., Sweating.
Insulator vs. Conductor
Adipose tissue acts as insulation to underlying tissues, thus limiting the degree of temperature change in deeper tissues
Blood and muscle have a relatively high, water content and thus readily absorb and conduct heat
Superficial heat
(1-3 cm)
Mild heating is when tissue temps are
less than 40 degrees C
reflex heating is?
apply indirect heat for the effected part by applied direct heat fortorso or opposite extremity or on the abdomen, this causes vasodilatation ( dilation in blood-vessel ) and a general increase in the blood flow, Blood flow then increases to the ischemic part
Reduction of muscle spasm
Deep heat can cause a reduction in the firing muscle spindles (Type II) and an excitation of 1b (GTO) which can cause relaxation
If tissue is heated b/t 40-45 deg C and a significant load is added, what occurs?
plastic deformation
