PT9111 - Lecture 19 (Modalities 3) Flashcards
Electrons
Negatively charged ions that are part of atoms
Electrical current
Flow of electrons from one area to another ([high] to [low])
Amperes
Rate of current
Voltage
Potential difference between high and low concentration areas of electrons
Ohm’s Law
Rate of current (I) is directly proportional to strength of driving force (V) and inversely proportional to resistance (R)
I=V/R
Name materials of high conductance
metal and water
Name materials of high resistance
Air, wood, glass
Tissues with high conductance
- High water content
- Blood
- Granulation Tissue
Tissues with high resistance
- Skin
- Bone
- Necrotic Tissue
What 3 factors increase skin impedance
- Cooler skin temp
- Hair and oil present
- Increased skin thickness
What 3 factors decrease skin impedance
- Remove excess hair
- Warming skin
- Washing skin
Describe the cathode and anode in terms of electric current
Cathode is black and is the negative pole that causes nerve depolarization and sends signal to positive/red anode where hyperpolarization then occurs down the nerve fibre so signal stays local
Name 6 characteristics that are different between anodes and cathodes
Cathode results in a [blank] reaction
Basic
Anode results in a [blank] reaction
Acidic
Name 3 types of currents
- Direct Current
- Alternating Current
- Pulsed Current
Direct Current
Continuous unidirectional movement of charged particles = net charge has polarity
Alternating Current
Uninterrupted bidirectional movement of electrically charge particles = no net charge
2 primary differences between direct and alternating current
Direct = flow of e- is unidirectional and polarity is constant
Alternating = Flow of e- reverses and no polar effects