AAET Flashcards Exam Study Questions and Answers Graded A 2023

AAET Flashcards Exam Study Questions and Answers Graded A 2023 What describes an atom in which the total number of electrons is not equal to the total number of protons, giving the atom a net positive or negative electrical charge - Ion What is the negatively charged particle in an atom? - Electron What has neutral particles, along with protons, and is found in the nucleus of an atom? - Neutrons Which particles of an atom are positively charged? - Protons What makes up the elements found in all matter? - Atoms What is the voltage inside the nerve cell membrane in a resting membrane potential? - - 90 to -70mV What is the major ion outside a cell membrane? - Sodium What is the major ion inside a cell membrane? - Potassium What is the physiological term when depolarization occurs it causes a muscle and/or nerve fiber to either respond to a stimulus completely if it reaches threshold or no response if the depolarization is insufficient to reach threshold? - All or non response What describes changing from a resting potential or polarized state to an excited state? - Depolarization What causes the inside of the cell to be more positively charged relative to its resting state? - Depolarization What describes when nerve cells are changed from an excited state back to a resting electrical potential or polarized state? - Repolarization What causes the inside of the cell to be more negatively charged relative to its resting state? - Hyperpolarization During the repolarization phase, sodium channels become inactivated and cannot be opened no matter how much depolarization occurs and no action potential can be generated no matter how strong the stimulus. What is this? - Absolute refractory period In the later stages of repolarization, a brief increase in the permeability to potassium occurs and this results in hyperpolarizing the membrane and returning it slowly to its resting value during which time an increasing number of sodium channels can be opened. If you give a strong stimulus, it might be possible for another action potential to occur. This time is known as the - relative refractory period Propagation of action potentials along myelinated axons from one Node of Ranvier to the next Node of Ranvier is called? - Saltatory conduction What is the name of the cells that are surrounding the axon to form the myelin sheath? - Schwann Cells What describes the periodic gaps in the insulating sheath (myelin) on the axon through which ion channels allow the flow of ions across the nerve membrane? - Nodes of Ranvier The length between two nodes of Ranvier is called? - Internodal length Forcing sodium out of the cell and potassium in is the function of what? - Sodiumpotassium pump What can increase or decrease the conduction velocity of a nerve? - Diameter of the axon and degree of myelination What type of fibers mediate pain, temperature, and autonomic function? - Unmyelinated fibers Nerve fiber bundles' having a common destination describes? - Fascicles Each individual fascicle is surrounded by connective tissue called? - Perineurium What is the connective tissue between individual axons called? - Endoneurium What is the name of the outer supportive layer of connective tissue which surrounds the whole nerve and binds fascicles to each other? - Epineurium What types of nerve fibers are myelinated? - Type-A fibers are myelinated fibers of somatic nerve that can innervate muscle or skin Type B fibers are myelinated preganglionic fibers Which type of nerve fiber is not fast and why? - Type C, unmyelinated Which nerve fiber is fast but not as fast as nerve fiber type A? - Type B - these fibers are myelinated but not as heavily as type A What is the communication link between the central and peripheral nervous system? - Axons What factors are important for fast conduction velocity? - Increased diameter and myelination of nerve fibers Where is the dorsal root ganglion located? - Outside of the spinal cord Where are the motor neurons located? - Gray matter of anterior horn in the spinal cord What is composed of sarcomeres and is responsible for muscle contracts? - Myofibrils A structural subunit and that contains actin and myosin filaments? - Sarcomere Which band contains only actin filaments? - I band Which band contains only myosin filaments? - H band Which band contains both actin and myosin filaments? - A band Where are the Z bands located? - At the end of each sarcomere What muscle fiber is called slow twitch muscle fiber? - Type I slow twitch, or "red" muscle, is dense with capillaries and is rich in mitochondria and myoglobin, giving the muscle tissue its characteristic red color. Slow twitch fibers contract for long periods of time but with little force What muscle fiber is called fast-twitch muscle fiber? - Type II a and Type II b Fast twitch fibers contract quickly and powerfully but fatigue very rapidly, sustaining only short, anaerobic bursts of activity before muscle contraction becomes painful. They contribute most to muscle strength and have greater potential for increase in mass. Type II b muscle fiber is white in color. What filament is contained in the center of sarcomere? - Thick myosin Which filament is extending from either side of the Z line? - Thin actin What is released from the sarcoplasmic reticulum that aids in muscle contraction? - Calcium What is the primary function of Sarcoplasmic Reticulum? - To store calcium ions (Ca^2+) Which two nerves originate directly from the cervical spinal nerve roots? - Dorsal Scapular and Long Thoracic Nerves Motor and sensory roots at each spinal level unite distal to the dorsal root ganglia to become? - Mixed spinal nerve What nerve roots contribute to the organization of the brachial plexus?? - C5-T1 What are the five components of the brachial plexus? - Five roots C5-T1 3 trunks - upper, middle, and lower 2 division of each trunk 3 cords Terminal nerves What nerve roots make up the upper trunk? - Anterior rami of C5-C6 roots What nerve root supplies the middle trunk? - C7 Which nerve roots make up the lower trunk? - C8-T1 What muscle is supplied by the long thoracic nerve? - Serratus Anterior Which nerve is purely sensory and receives fibers from C8-T1 roots? - Medial Antebrachial Nerve Where is the location for Erb's point? - Triangle between the clavicle and the Sternocleidomastoid muscle Lumbar Plexus is formed by what nerve roots? - L1-L4 The lumbosacral plexus is formed by which nerve roots? - L1-S4 The relationship between voltage, current and resistance in the equation E= Ix R is known as? - Ohms Law What is name of the law used to calculate the flow of electricity, E (Voltage) = I (current)xR(resistance)? - Ohms Law What is an interconnection of components such that currents flow in one or more closed loops? - Circuit What is a sample of a simple circuit? - I=I1+I2+I3 What is an electrical device that provides specific resistances used to control current and voltage in electrical circuits? - Resistors What reduces total resistance and is the sum of individual currents going through each resistor? - Resistors in Parallel The current flows in one path and is the same flowing through each resistor and can be directly added together to calculate a net resistance. This best describes? - Resistors in series The process of generating a binary number proportional to the value of the analog input voltage. This best describes? - Analog to Digital conversion There are lines or dots on the screen that represent divisions and correspond with the current sensitivity and sweep speed (timebase). The vertical divisions (top to bottom) represent - amplitude and we refer to this as? - Vertical resolution There are lines or dots on the screen that represent divisions and correspond with the current sensitivity and sweep speed (timebase). The horizontal divisions (left to right) represent - latency or time - we refer to this as? - Horizontal resolution The computer rewrites the analog line into a series of dots from which the line is recreated. This is called analog to digital conversion and these dots are called? - Data points In NCS, what describes the summation of the traces by the total number of traces collected in an effort to eliminate background noise? - Averaging What describes the effect of passing some bands of frequencies while attenuating others? - Filtering Effects Varied fast and slow fibers cancel one another as one phase of the slow fibers reach the recording electrode, as the trailing phase of the fastest fibers pass the same recording electrode causing an apparent loss of amplitude. - Phase cancellation The hardware component used to increase the size of the small physiologic signal: - amplifier What describes the parameters of 2-10 hz (motor) and 20-30 Hz (sensory) and eliminates or attenuates (reduces) unwanted slow frequencies? - Low frequency filters What describes the parameters of 5-20 kHz (motor) and 2-3 kHz (sensory) and eliminates or attenuates (reduces) unwanted fast frequencies? - High frequency filters What describes the horizontal measurement of time displayed on the screen? - Sweep speed/time base What describes the vertical measurement of amplitude of the waveform on the screen? - Sensitivity/Gain Where should the vertical cursors be placed when measuring a sensory nerve action potential? - Onset and Peak of waveform What type of stimulator delivers an adjustable current through the stimulating electrodes independent of their impedance? - Constant current What describes the amount of electrical energy applied to produce a measureable response measured in volts or milliamps? - Intensity What describes the length of time a stimulus is applied; measured in milliseconds and limited to a maximum of 1 msec? - Duration The negative terminal of the stimulating electrode. - Cathode The positive terminal of the stimulating electrode - Anode What describes the process when hyperpolarization occurs under the anode preventing the depolarization that occurs under the cathode from passing, thus causing a reduction in resting potential? - anodal block What describes the process when stimulation spreads to nearby nerves resulting in erroneous results? - Volume conduction What describes an unwanted electrical signal that obscures the desired response recorded at the time the stimulus is applied? - Stimulus artifact What describes when an increase in stimulus no longer increases the size of the response? ? - Supramaximal stimulation A nerve root lesion proximal to the dorsal root ganglia, best describes? - Preganglionic A nerve root lesion distal to the dorsal root ganglia best describes? - Postganglionic Which nerve root lesions have NCS findings that indicate absent motor responses and preserved sensory responses? - Pre ganglionic Which nerve root lesions have NCS findings that indicate absent motor responses and absent sensory responses? - Post ganglionic What are the effects of a preganglionic lesion? - Most often, the lesion represents root avulsion from the spinal cord. The muscles supplied by the nerve root will atrophy. Surgical repair is impossible. Preganglionic injuries have limited spontaneous recovery. What describes the length of time a stimulus is applied; measured in milliseconds and limited to a maximum of 1 msec? - Duration The NCS term for lesions in a specific and definable location; usually found with short distance nerve conduction studies and are usually demyelinating lesions - Focal The NCS term when there is an amplitude and area difference in a response that is seen between the distal and proximal stimulation sites of a nerve. It is seen most often in demyelinating disorders when all technical factors have been eliminated. - Conduction block The term for peripheral neuropathy that essentially involves all nerves in a lengthdependent fashion, to a relatively equal extent. - diffuse process The term for peripheral neuropathy that involves one or multiple nerves in an asymmetric or patchy distribution - multifocal disorder what is the term for a disease or disorder affecting the myelin surrounding a peripheral nerve? The nerve conduction study will show conduction velocity slowing and/or conduction block - Demyelination What is the term for a loss of nerve fibers due to disease or injury? - Axonal loss What is a measurement of the time needed for the stimulus to travel from stimulation point to recording point(recording point may be the initial takeoff, the first positive peak or the negative peak)? - Latency The measurement of the vertical size of the waveform - Amplitude A measurement of time in meters per second between two points. It is calculated from the fastest fibers as the difference in distance divided by difference in time - Conduction velocity What is the term used to represent the duration and amplitude of a motor response? It is measured in mV and ms (for MNC, its most useful place) and helps differentiate between a conduction block and simple dispersion - Area The measurement from the first deviation to the baseline to the next crossing of that same baseline - duration The interval from the onset of a polarity change of a potential to its peak - rise time the values routinely used as references when performing nerve conduction studies. A lab either establishes its own values or used another reputable lab's values - normal values Over longer conduction distances, what is the term for a long duration of the negative peak of a CMAP and SNAP? - Temporal dispersion A decrease in amplitude across a proximal nerve segment compared to the distal amplitude? - Amplitude drop What are the three most important technical issues encountered when performing infant or children nerve conduction studies? - Measurement, electrode size, and stimulation intensity What happens to the CMAP amplitude in pediatric nerve conduction studies? - It increases in direct proportion to age The process of myelination is age dependent, beginning in utero. What is the approximate value of nerve conduction velocities in full-term infants? ? - Approximately half that of adult normal values: Accordingly nerve conduction velocities of 25 to 30 m/s are normal at birth Conduction velocity rapidly increases after birth, reaching approximately 75% of adult normal values by age 1 year, and the adult range by - 3 to 5 years At what age do sensory NCV reach mean adult values? - 5 years of age It is not uncommon to see bifid morphology on sensory nerve action potentials in infants and children between the ages 3 months and 4-6 years. Explain why - Bifid morphology occurs due to some fibers having already been fully myelinated whereas others have not and trail behind. This is not unusual to see bifid SNAPS between the age of 3 months and 4-6 years. They are completely normal and as fibers of the second peak myelinate the second peak moves to the left and merges with the first peak, forming a larger sensory response, as typically seen in adults. Axonal degeneration that progresses from the place of injury along the axon (i.e. distal to a lesion) - Wallerian Degeneration Nerve injury defined as, failure of nerve conduction in the absence of structural changes (primarily demyelinating as seen with slowing of the nerve conduction studies without axonal damage, meaning good prognosis) - Neurapraxia Nerve injury defined as, nerve conduction slowing without complete block (axons and myelin disrupted, but supporting connective tissue is intact, allowing reinnervation of the axons) - Axonotmesis Nerve injury defined as, partial or complete severance of a nerve, with disruption of the axon, its myelin sheath and connective tissue (mixed axonal and demyelinating when both conduction time and amplitude are affected) - Neurotmesis A recording from any motor nerve, activated by antidromic stimulation that travels centrally to the spinal cord through interneurons and anterior horn cells, then orthodromically from the spinal cord to the muscle - F wave (origin