Electrotherapy I Lecture Notes PDF

Name of Department : Physical Therapy and Rehabilitation Course Code and Name : Electrotherapy I Course Week : 2.Week Course Day and Time : Monday 14:00 – 17:50 Course Credit/ACTS Information : 3/4 Examination Type and Gradin...

Name of Department : Physical Therapy and Rehabilitation Course Code and Name : Electrotherapy I Course Week : 2.Week Course Day and Time : Monday 14:00 – 17:50 Course Credit/ACTS Information : 3/4 Examination Type and Gradings : Instructor’s Name & Surname : Busenur KARAGÖZ E-mail & Phone: : [email protected] Instructor’s Room : Office Hours : GBS Link : ALMS Link : AVESIS Link :  | 14 WEEKS’S COURSE CONTENTS | 1.Week Introduction to Electrotherapy, 9.Week Electrodiagnostic Tests Electrophysical Principles 10.Week TENS (Transcutaneous Electrical 2.Week Electrical Properties of Cells and Tissues Stimulation) 3.Week : Muscle Contraction Mechanism 11.Week NMES (Neuromuscular Electrical 4.Week Straight Currents and Iontophoresis Stimulation) 5.Week Galvanic Current 12.Week FES (Functional Electrical Stimulation) 13.Week Russian Current 6.Week Faradic Current 7.Week Sinusoidal Current 14.Week Interferential Current MIDTERM EXAM 15.Week Diadynamic Current FINAL EXAM  | WEEKLY LEARNING OUTCOMES | o Knowing the electrical properties of cells and tissues o Defining the membrane potential o Defining the sodium potassium pump o Learning the concepts of polarization-depolarization-repolarization o Defining the action potential  | ABOUT THE PREVIOUS COURSE | o General effects of electricity; Heat, chemical, physiological, mechanical , electromagnetic o The net electron movement in the substance is called electric current. Its unit is ampere. o Electric currents have the following effects on objects: Thermal,electrolytic, magnetic o If there is no potential difference between two points, electrons do not move. o The amount of current passing through body tissues depends on the resistance of the tissues applied. o The physiological effects of electric current;Cell,tissue,segment,systemic o Cancer and pacemaker are contraindications for electrostimulation o There is a risk of chemical burns in direct currents because the current is one-way o Excitable tissuesTissues with high water content,nerve,muscle,blood,cell membranes o Muscles are stimulated to contract or relax, nerves to provide analgesia or increase movement, and bones and wounds to heal. o Bone and fat tissue have high impedance, while nerve and muscle tissue have low impedance. o Placing the electrodes close to each other keeps the effects superficial, while placing them farther away allows them to reach deep tissues.  | DAILY FLOW | 14.00-14.50/ Electrical Properties of Cell and Tissue 15.00-15.50/ Membraine potential – Sodium Potassium Pump 16.00-16.50/ Polarization-Depolarization- Repolarization 17.00-17.50/ Action Potential  | IMPULSE FORMATION | Formation and transmission of impulse When a nerve cell is stimulated, the nerve cell's reception of the stimulus is called an impulse. The minimum stimulus intensity that must be given for an impulse to occur in a nerve cell is called the threshold value. If the stimulus intensity is below this threshold value; no impulse occurs in the nerve cell. If the stimulus is at or above the threshold value; the nerve cell responds to the stimulus with the same intensity. This is called the all-or-nothing principle. While a single neuron obeys the all-or-nothing principle, a nerve bundle does not obey this principle because the threshold value of each neuron in the nerve bundle is different from the other.  | MEMBRANE POTENTIALS | All cells have a potential difference separated by the cell membrane when they are at rest. The inside of the cell membrane is negatively charged compared to the outside.This potential difference is called the resting membrane potential. Resting membrane potential is around 90mV for a muscle cell and 70mV for a nerve cell.  | MEMBRANE POTENTIALS | The resting membrane potential is formed by the presence of the following two factors: Different distribution of ions inside and outside the cell. Different permeability of the cell membrane to different ions (It is selectively permeable)  | MEMBRANE POTENTIALS | There are 2 important factors in the negative resting potential. K Leakage Channels: K, which is in high concentration in the cell (excessive in the cell because it is necessary for enzymatic reactions), slowly leaves the cell through leakage channels that do not have gates and helps the cell interior shift to negativity. Na K Pump: While the pump is working, 3 Na ions are released from the cell and 2 K ions enter the cell. In other words, the cell loses a positive ion. ATP is consumed in this case because the pump is used. Polarization: When the nerve cell is at rest, the outside of the cell is positively charged and the inside of the cell is negatively charged. This state of the cell is provided by the Na – K pump. It carries K ions into the cell while removing Na ions from the cell and this state is called polarization. Depolarization: When the nerve cell shows activity, that is, when it transmits an impulse, the permeability of the membrane to Na+ ions increases approximately 500 times and Na+ ions enter at a great speed. Since there are both Na and K ions in the cell, the inside of the cell becomes positive rapidly. In this case, polarization is disrupted and the potential difference increases to 35-+40 millivolts. This state is called depolarization.Since the Na K pump does not function during depolarization, ATP is not consumed. Repolarization: A nerve cell that receives a stimulus must return to its previous state in order to receive a second stimulus. For this, in the nerve cell; Na is pumped out of the cell and K is pumped into the cell by active transport. Thus, the outer part of the nerve cell becomes positive (+) and the inner part becomes negative (charged). This stage is called repolarization. Since the Na K pump functions in repolarization, ATP is consumed. Hyperpolarization: the membrane potential becomes more negative than the resting potential level (more K+ outflow from the cell) and stimulation becomes more difficult; the electrical potential formed at this time is called hyperpolarization.  | ACTION POTENTIAL | The rapid change in the membrane potential of an excitable cell is called an action potential, and this change triggers the formation of an impulse. 0: Resting membrane potantial 1: Depolarization 3: The membrane potential is at its peak 4:Repolarization 5:Hyperpolarization phase  | ACTION POTENTIAL | The rapid change in the membrane potential of an excitable cell is called an action potential, and this change triggers the formation of an impulse. The first action potential formed by the entry of sodium ions into the cell creates another action potential in the next region of the membrane. After the action potential is formed, it continues successively along the axon. The axon diameter and whether it carries a myelin sheath affect its speed. The larger the axon diameter, the higher the conduction rate. In myelinated axons, the ion current occurs only in the nodes of Ranvier. For this reason, the conduction seen in myelinated axons is called skip conduction  Muscles and nerves are both integral components of the body's nervous system, and they exhibit distinct electrical properties that play essential roles in their respective functions. Electrical Properties of Muscle 1. Resting Membrane Potential: Muscle cells, like all cells, have a resting membrane potential due to differences in ion concentrations across their cell membranes. In resting muscle cells, the interior is negatively charged compared to the extracellular environment. 2. Action Potential: Muscle cells can generate action potentials, which are rapid changes in membrane potential that propagate along the length of the cell. In skeletal muscle, an action potential triggers muscle contraction. 3. Excitability: Muscles respond to electrical stimuli by contracting. The threshold for excitation varies among different muscle types. 4. Ion Channels: Muscle cells possess voltage-gated ion channels, such as sodium (Na⁺) and potassium (K⁺) channels, which play a key role in generating and propagating action potentials. 5. Calcium Signaling: In muscle contraction, calcium ions (Ca²⁺) play a crucial role. Voltage changes during action potentials trigger the release of calcium ions from the sarcoplasmic reticulum, leading to muscle contraction. Electrical Properties of Nerve: 1. Resting Membrane Potential: Nerve cells, or neurons, also have a resting membrane potential, which is maintained by ion pumps and channels. 2. Action Potential: Neurons generate and transmit action potentials, which are crucial for communication between different parts of the nervous system. These electrical signals allow information to be relayed over long distances within the body. 3. Excitability: Neurons are highly excitable and can respond to a variety of stimuli, including neurotransmitters released by other neurons. 4. Synaptic Transmission: Electrical impulses in neurons trigger the release of neurotransmitters at synapses. These chemicals then relay the electrical signal from one neuron to the next. 5. Ion Channels: Similar to muscle cells, neurons have various types of ion channels, including sodium and potassium channels, that are crucial for generating action potentials and transmitting signals. 6. Myelin Sheath:Many neurons are surrounded by a myelin sheath, which is formed by glial cells. Myelin acts as an insulator, allowing for faster conduction of electrical signals along the nerve fiber. Both muscle and nerve tissues rely on the movement of ions and changes in membrane potential to carry out their respective functions. The differences in their electrical properties reflect their distinct roles in the body's overall physiological processes.  | WHAT TO TAKE HOME? | o The rate at which the action potential repeats along the axon (impulse conduction rate) depends on the structural characteristics of the cell. (Axon diameter and myelin sheath) o The intensity of the stimulus does not affect the impulse conduction rate. o The minimum stimulus intensity required for an action potential to occur in a neuron is called the threshold value. o A neuron does not respond to stimuli below the threshold value, while it responds in the same way to all stimuli above and above the threshold value. (All or nothing principle) o While a single neuron obeys the all or nothing principle, a nerve bundle does not obey this principle. Because the threshold value of each neuron in the nerve bundle is different from the other. o ATP is used in polarization and repolarization o Resting membrane potential is around 90mV for a muscle cell and 70mV for a nerve cell. o There are 2 important factors in the negative resting potential: K Leakage Channels and Na K Pump  | QUESTIONS AND SUGGESTIONS | When the difference between the charge inside and outside of an axon is further apart, it is called: Action Depolarization Hyperpolarization Polarization Resting  | QUESTIONS AND SUGGESTIONS | Which of the following is not among the electrical properties of muscles? Resting Membrane Potential Action Potential Excitability Ion Channel Myelin Sheat  | RECOMMENDED WEEKLY STUDIES | o 2 days a week 1 hour each will be enough  | REFERENCES | İleri Egzersiz Fizyolojsi, Jonathan K.Ehrman,Dennis J.Kerrigan, Steven J.Keteyian, 2018 Elektroterapide Temel Prensipler ve Klinik Uygulamalar, Nihal Şimşek Nuray Kırdı, 2016  | ABOUT THE NEXT WEEK | o Muscle contraction mechanism  ………….. – ………………………… Since course presentations are private, using the texts and images contained herein on social media or else without permission from the course instructor is against the regulations Law No. 6698. "The supreme guide in life is knowledge”