Electricity and Magnetism Overview

Electric Lines of Force

• Represent the direction of the electric field
• Indicate the direction a positive charge would move in the field
• Lines start from positive charges and end on negative charges
• Lines never intersect
• Lines are closer together where the field is stronger

Laws of Electromagnetic Induction

• Faraday's Law: The magnitude of an induced electromotive force (EMF) in a circuit is directly proportional to the rate of change of magnetic flux through the circuit
• Lenz's Law: The direction of the induced EMF is such that it opposes the change in magnetic flux that produced it

Factors Affecting Capacity of Condenser

• Area of Plates: Larger area, higher capacitance
• Distance between Plates: Smaller distance, higher capacitance
• Dielectric Constant of Medium: Higher dielectric constant, higher capacitance

Rheostat in Regulation of Intensity of Current

• A variable resistor used to control the flow of electric current
• Alters resistance, thus changing the current
• Higher resistance, lower current flow
• Used to adjust the intensity of current in electrotherapy

Prevention of Electric Shock

• Use properly insulated equipment and wiring
• Avoid touching electrical appliances with wet hands
• Ground all electrical appliances
• Use a Ground Fault Circuit Interrupter (GFCI)

Working of Diode Valve

• Allows current flow in only one direction
• Consists of a cathode and an anode
• Electrons flow from cathode to anode
• Used for rectification and signal modulation in electronics

Switches and Power Plugs

• Switches interrupt the flow of current
• Power plugs connect electrical appliances to the power source
• Three-pin plugs provide grounding for safety

Prevention of Earth Shock

• Earth wires connected to the metal body of an appliance
• Provide a low resistance path for fault currents to ground, preventing electrical shocks
• Essential for electrical safety

Types of Capacitors

• Electrolytic: High capacitance value, polarized
• Ceramic: Small capacitance, high reliability
• Film: Stable capacitance performance, low leakage current
• Variable: Adjustable capacitance values

Properties of Magnets

• Force of Attraction/Repulsion: Opposite poles attract, like poles repel
• Magnetic Field: A region around a magnet where magnetic force can be detected
• Magnetic Permeability: Ease with which a material can be magnetized
• Magnetic Retentivity: Ability of a material to retain its magnetism after removal of the magnetizing force

Light and Power Circuits

• Light circuits: Provide illumination, generally have lower current ratings
• Power circuits: Supply power to appliances, typically have higher currents
• Fuse: A safety device that protects the circuit from overcurrents
• Fuse function: Melts and disconnects the circuit when current exceeds its rating, preventing overheating and potential fire

Transformer: Principle, Construction, Working, and Uses

• Principle: Based on electromagnetic induction
• Construction: Two coils of wire wound around a common iron core
• Working: Alternating current in one coil induces an EMF in the other coil
• Types: Step-up (increases voltage), step-down (decreases voltage)
• Uses: Power distribution, electrical appliances, electronics

Accommodation and Surging

• Accommodation: The nerve gradually adapts to a constant stimulus, decreasing its response
• Surging: Increase in the strength of a current to overcome accommodation

Electrode Placement in TENS

• Active Electrode: Placed over the painful area
• Inactive Electrode: Placed on a remote non-painful area

Local Contraindications in Stimulating Facial Muscles

• Eye Region: Can cause irritation or even blindness
• Temporomandibular Joint: Can exacerbate pain or dysfunction
• Thyroid Gland: May affect hormone production

Electrotherapy Management of a New Born with Erb’s Palsy

• Goal: Promote nerve regeneration and restore function of the affected arm
• Electrotherapy: Use of various currents to stimulate muscles and promote nerve recovery
• Specific currents: Low-frequency TENS, Russian currents
• Treatment plan: Customized based on the severity and duration of the palsy

Indications of Diadynamic Currents

• Pain management
• Muscle stimulation
• Nerve regeneration

Selective Impulses

• Series of impulses delivered at shorter intervals, interspersed with periods of rest
• Used to minimize accommodation by constantly varying the stimulus intensity

High TENS

• High-frequency TENS with higher intensity
• Produces an analgesic effect by blocking pain signals
• Often used for acute pain

Physiological Effect of Interrupted Direct Current

• Produces a strong, tetanizing muscle contraction
• Used for muscle strengthening and promoting circulation

Faradic Foot Bath

• Applying a faradic current to a foot bath
• Stimulates muscles and improves circulation in the feet
• Often used for conditions like Raynaud's phenomenon or foot pain

Reduction of Gravitational Oedema with Low Frequency Electrotherapy

• Low-frequency currents stimulate muscle contractions and improve lymphatic drainage, helping reduce oedema
• Specific currents: Interrupted direct currents, diadynamic currents
• Treatment plan: Multiple sessions with electrode placement strategized for optimal lymphatic drainage

Physiological and Therapeutic Effects of Interrupted Direct Current

• Physiological: Stimulates muscle contractions, increases blood flow
• Therapeutic: Reduces pain, improves muscle strength, promotes tissue healing
• Selective impulses: Minimizes fatigue and discomfort during treatment

Physiological and Therapeutic Effects of Faradic Type of Current

• Physiological: Stimulates muscle contractions, reduces fatigue
• Therapeutic: Muscle strengthening, pain management, improving muscle tone

Wallerian Degeneration and Regeneration

• Wallerian degeneration: Breakdown of the distal segment of a damaged nerve fiber
• Regeneration: Process of re-growth of the nerve axon from the proximal stump to the distal segment

Propagation of Action Potential

• Wave of depolarization that travels along the nerve fiber
• Mechanism: Sodium ions flow into the neuron, changing its electrical potential

Faradic Galvanic Testing

• Assessment of nerve conduction using different types of currents
• Faradic current: Tests the integrity of the motor nerve fibers
• Galvanic current: Assesses the integrity of the sensory nerve fibers

Spontaneous Potentials of Electromyography

• Electrical activity recorded from a muscle at rest
• Indicates nerve damage or abnormal muscle activity

Rheobase, Chronaxie, and Utilization Time

• Rheobase: The minimum current intensity needed to elicit a muscle contraction
• Chronaxie: The time required for a current twice the rheobase intensity to elicit a muscle contraction
• Utilization time: The time required for a specific current intensity to elicit a muscle contraction

Seddon’s Classification of Peripheral Nerve Injuries

• Neurapraxia: Loss of function without nerve fiber damage
• Axonotmesis: Disruption of the nerve axon, but the sheath remains intact
• Neurotmesis: Complete disruption of the nerve, including the sheath

Current Parameters for Treatment of Carpal Tunnel Syndrome

• Use low-frequency, low-intensity currents to stimulate the median nerve and reduce inflammation
• Specific currents: Interrupted direct currents, diadynamic currents
• Treat for 15-20 minutes, several times per week

Electrotherapy Management of Saturday Night Palsy

• Goal: Promote nerve regeneration and restore function of the affected arm
• Electrotherapy: Use of various currents to stimulate muscles and nerve recovery
• Specific currents: Low-frequency TENS, Russian currents
• Treatment plan: Customized based on the severity and duration of the palsy

Low Frequency Application in Right Side Radial Nerve Injury

• Goal: Promote nerve regeneration and improve function of the affected muscles
• Electrotherapy: Use of low-frequency currents to stimulate muscles and promote nerve recovery
• Specific currents: Interrupted direct currents, diadynamic currents
• Treatment plan: Multiple sessions, electrode placement strategically positioned to stimulate muscles and nerve fibers

Electrotherapy Treatment for Ulnar Nerve Injury

• Goal: Promote nerve regeneration and improve function of the affected muscles
• Electrotherapy: Use of various currents to stimulate muscles and nerve recovery
• Specific currents: Low-frequency TENS, Russian currents
• Treatment plan: Customized based on the severity and duration of the injury

Procedure and Interpretation of Strength Duration Curve

• Procedure: A series of electrical stimuli of different durations and intensities are applied to a muscle
• Interpretation: The relationship between the stimulus duration and the intensity required to elicit a muscle contraction is plotted
• Information: Provides information about nerve excitability and muscle response

Electrotherapy Management of Sciatic Nerve Lesion

• Goal: Promote nerve regeneration and improve function of the affected leg
• Electrotherapy: Use of various currents to stimulate muscles and promote nerve recovery
• Specific currents: Low-frequency TENS, Russian currents
• Treatment plan: Customized based on the severity and duration of the lesion

Pain Gate Theories

• Theory: Pain signals from peripheral tissues are modulated by the interaction of various nerve fibers and their influence on the spinal cord
• Mechanism: Activation of large-diameter nerve fibers (A-beta) closes the "pain gate" in the spinal cord, reducing pain transmission
• Use in electrotherapy: High-frequency TENS and other modalities stimulate A-beta fibers and reduce pain transmission

Indications of Diadynamic Currents

• Pain management
• Muscle stimulation
• Nerve regeneration

Russian Current

• Medium-frequency alternating current
• Uses: Muscle strengthening, pain management, and improving muscle coordination

Electrotherapy Management for Stress Incontinence

• Goal: Strengthen pelvic floor muscles to improve bladder control
• Electrotherapy: Use of various currents to stimulate the pelvic floor muscles
• Specific currents: Interrupted direct currents, Russian currents
• Treatment plan: Multiple sessions with electrode placement directed to target pelvic floor muscles

Faradic Galvanic Testing

• Assessment of nerve conduction using different types of currents
• Faradic current: Tests the integrity of the motor nerve fibers
• Galvanic current: Assesses the integrity of the sensory nerve fibers

This quiz covers key concepts in electricity and magnetism, including the behavior of electric lines of force and laws of electromagnetic induction. You'll also explore factors affecting capacitor capacity and the role of rheostats in regulating current intensity. Test your understanding of these fundamental principles.