Diathermy Flashcards
Define electron.
-a small fundamental particle of matter that has a negative charge.
How do electrons work?
- they travel in orbit around the central nucleus (+) and are held in place by the attraction of the positive protons.
- can be dislodged and moved to an outer orbit of an adjacent atom
- when electrical force (voltage) applied to a circuit electrons become organized and directional from negative to positive
- when an electron leaves an atom that atom becomes more positively charged and the atom receiving the electron becomes more negative
What is static electricity?
- Two surfaces involved: An excessive amount of electrons on one surface and a deficit of electrons on the other surface after being rubbed together
- The electrical current is beacuse electrons are moving successively from one atom to another NOT moving along a conductor
What is true about two objects with the same polarity?
the objects will repel each other
What is true about two objects with the opposite polarity?
the objects attract each other
Define conductor.
Any material which permits the easy movement of electrons in a circuit.
Ex: metal, liquid, body tissue
-usually good conductors of electricity are good conductors of heat
Define ohm.
-the unit of measurement of resistance and defined as one (1) volt applied across a resistance that causes 1 ampre (amp) of current to flow
Why is resistance important?
-different electrical conductors have different amounts of resistance to the flow current
Define ampre.
the measurement of the intensity of the electrical current
Define volt.
the measurement of pressure or potential of electrical current
Define resistance.
impedence or opposition which is dependent upon the intensity and potential of the electrical current
How does resistance, ampre, conductors, and volt work together?
- Conductors have different amounts resistance to the flow current.
- Resistance to the flow of electrons dependent on the ampres, and volts (ohm’s law: Voltage= Current x Resistance)
- ampres and volts are used to measure output of many electrotherapy machines
- as electrical current flows through a conductor, part of the current is dissipated due to the resistance of the conductor to the flow of the current
What are the local effects of shortwave diathermy?
Local = at the site of healing tissue
- Marked hyperemia
- marked increase in lymph flow
- increase in the volume of the area treated due to increase in blood and lymph in the area
- increase in glandular secretion if a gland is treated
- increased extensibility of connective tissue structures
What are the general effects of shortwave diathermy?
General = remote to area treated
- rapid dilation of peripheral blood vessels
- rise in body temperature and in the operation of all mechanisms of heat loss
- marked sedative effect
- general perspiration
- consensual vasodialtion
What are the selective effects of heating tissues?
- depends upon the presence of charged particles called ions held in solution in the body fluids
- body tissues with high fluid content = blood vessels and muscles
- areas of fatty accumulation = danger for producing burns because low conductivity and high resistance
- lack of vascular network to dissipate heat in these areas