Exercise 3: Neurophysiology of Nerve Impulses Worksheet Assignment Due: Week 4 Student instructions: Follow the step-by-step instructions for this exercise found in your text and record your answers in the spaces below. Submit this completed document by the assignment due date found in the Syllabus. Please make sure that your answers are typed in RED. Please type your Name and Student ID Number here: Charles Coon 4048223 Eliciting a Nerve Impulse Activity 1: Electrical Stimulation
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Exercise 3: Neurophysiology of Nerve Impulses Worksheet Eliciting a Nerve Impulse Activity 1: Electrical Stimulation 1. Do you see any kind of response on the oscilloscope screen? No there was no response‚ the line was flat 2. What was the threshold voltage‚ or the voltage at which you first saw an action potential? 3.0V 3. How does this tracing compare to the one that was generated at the threshold voltage? At 3.5V the high & low peaks were just slightly above and below respectively
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sciatic nerve from a cane toad‚ Bufo marinus. Compound action potentials are the total sum of action potentials from the multitude of neurons that compose a nerve (Stillman‚ 2005).
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E X E R C I S E 3 Neurophysiology of Nerve Impulses O B J E C T I V E S 1. To define the following terms: irritability‚ conductivity‚ resting membrane potential‚ polarized‚ sodium-potassium pump‚ threshold stimulus‚ depolarization‚ action potential‚ repolarization‚ hyperpolarization‚ absolute refractory period‚ relative refractory period‚ nerve impulse‚ compound nerve action potential‚ and conduction velocity. 2. To list at least four different stimuli capable of generating
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2-4: 1. What did you observe when the glass rod contacted the nerve? An action potential is generated as I touch the rod to the nerve. 2. How does this tracing compare with the other tracings you have generated? The tracing is identical to the tracing generated at the threshold voltage. 3. What did you observe when the heated glass rod contacted the nerve? An action potential is generated when you touch the heated rod to the nerve‚ through a thermal stimulus. 4. How does this trace compare
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maximal voltage here: 6.0 V Activity 2: Mechanical Stimulation 1. When the glass rod is touching the nerve‚ what do you see on the oscilloscope screen? The nerve’s action potential to stimuli 2. How does this tracing compare with the other tracings you have generated? They are traced in the same fashion Activity 3: Thermal Stimulation 1. What happens when the heated rod touches the nerve? Action potential in increased 2. How does this trace compare to the trace that was generated with the
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measure the electrical activity emitted from the muscle and nerves that control the muscle. This electrical activity is seen when a neuron ignites an action potential that activates the muscle fibers that were innervated by the motor neuron. This study aimed to view how the muscles electrical activity changed with voluntary contractions‚ and evoked stimulation of the abductor pollicis brevis muscle‚ and measure nerve conduction velocity and the affect of coactivation. Research in the use of electromyography
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potassium than sodium. When synaptic activity makes the cell less negative‚ the sodium channels open. If the cell voltage goes past a certain level‚ an action potential is produced. Action potentials‚ changes in the membrane potential that happen when a nerve cell membrane is stimulated (Ritchison)‚ happen within milliseconds. After the voltage has reached the threshold potential‚ more voltage-gated sodium channels open and the voltage of the membrane reaches its most positive value. The voltage-gated sodium
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The Ionic mechanism and propagation of action potentials. The action potential is the result of a large‚ sudden increase in sodium permeability of the membrane. The resulting rush of sodium ions into the membrane and accumulation of positive charge on its inner surface drives the potential towards Ena. This is followed by repolarisation‚ whereby there is a large increase in the membranes permeability to potassium ions‚ hence the membrane returns to Ek. Explanation of the (ionic) mechanisms underlying
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PhysioEx 9.0 Exercise 3 Neurophysiology of Nerve Impulses A C T I V I T Y 1 The Resting Membrane Potential 1. Explain why increasing extracellular K_ reduces the net diffusion of K_ out of the neuron through the K_ leak channels. Increasing the extracellular potassium reduces the concentration gradient‚ and less potassium diffuses out of the neuron and into the cell. 2. Explain why increasing extracellular K_ causes the membrane potential to change to a less negative value.
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