PhysioEx Exercise 3: Neurophysiology of Nerve Impulses is an interactive laboratory simulation that allows students to explore the physiological processes involved in the transmission of nerve impulses. The second activity of this exercise focuses on the role of ion channels in the generation and propagation of action potentials.
In this activity, students are first introduced to the concept of action potentials, which are electrical signals that are generated by neurons in response to stimuli. Action potentials are generated when the membrane potential of a neuron becomes depolarized, meaning that the voltage across the membrane becomes more positive. This depolarization is caused by the flow of ions across the membrane through ion channels, which are special proteins that are embedded in the membrane.
There are two main types of ion channels: voltage-gated ion channels and ligand-gated ion channels. Voltage-gated ion channels are sensitive to changes in the membrane potential, and they open or close in response to these changes. Ligand-gated ion channels are activated by specific molecules, called ligands, which bind to the channel and cause it to open.
In the second activity of PhysioEx Exercise 3, students are asked to investigate the role of ion channels in the generation and propagation of action potentials. To do this, they use a simulated neuron and apply various stimuli to it to see how the neuron responds. By adjusting the stimuli and observing the resulting changes in the neuron's membrane potential, students can learn about the different types of ion channels and how they contribute to the generation and propagation of action potentials.
One of the key concepts that students learn in this activity is the importance of the ionic gradient in the generation and propagation of action potentials. The ionic gradient is the difference in concentration of ions on either side of the membrane, and it plays a critical role in the movement of ions across the membrane. When the ionic gradient is disturbed, it can lead to changes in the membrane potential, which can in turn trigger the opening or closing of ion channels.
Overall, the second activity of PhysioEx Exercise 3 is an important learning opportunity for students interested in understanding the physiological processes involved in the transmission of nerve impulses. By interacting with a simulated neuron and applying various stimuli, students can gain a deeper understanding of the role of ion channels in the generation and propagation of action potentials and the importance of the ionic gradient in this process.
Physio Ex Exercise 3 Activity 2
Which of the following is not one of the ways that the body can increase the force produced by a skeletal muscle? If a nerve, rather than an axon, had been used in the lidocaine experiment, the responses recorded at R1 and R2 would be the sum of all the action potentials called a compound action potential. Your answer: moderate-intensity pressure. Which of the following modalities will induce the largest amplitude receptor potential in the olfactory receptor? What do your results suggest about the number or state open or closed of Na+ channels in the resting membrane of a neuron? Your answer: As the stimulus frequency increases, the muscle force generated by each successive stimulus will increase. An action potential is generated when the membrane potential reaches threshold. How well did the results compare with your prediction? Eating puffer fish can cause numbness of the lips, probably because a. I predicted that the moderate-intensity chemical would induce the largest amplitude receptor potential, but that was in reference to the options given which included pressure, light, and heat stimuli as well, but not the option of a high-intensity chemical modality. Describe the force of contraction with each subsequent stimulus.
In the control, the amplitudes of the action potentials at R1 and R2 are the same. Review Sheet Results A very intense stimulus can sometimes stimulate sensory neurons that have evolved for a different modality. This phenomenon is known as 3 Review Sheet Results You correctly answered: wave summation. You correctly answered: The sensory end of this nerve is less specialized. The generation of an action potential uses voltage-gated Na+ channels.
What passive channels are likely found in the membrane of the olfactory receptor, in the membrane of the Pacinian corpuscle, and in the membrane of the free nerve ending? There will be a limit to this increase. Your answer: Neither the Pacinian corpuscle nor the free nerve ending are likely to have the isoamylacetate receptor because neither of them responded to the chemical stimuli exposed to them, which is the adequate stimuli for olfactory receptors. Post-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. All of these make it harder to generate a second action potential With a prolonged stimulus that is just above more depolarized than threshold, you would expect to get additional action potentials when the membrane has complete a. A glucose standard curve is a tool used to measure the FPG levels taken from several patients to diagnose the presence or absence of diabetes.
Wave summation is achieved by You correctly answered: increasing the rate of stimulus delivery frequency to the muscle. Your answer: No, the voltage remained the same through my predications. When voltage-gated Na+ channels between R1 and R2 are blocked with TTX, an action potential is still recorded at R1 because a. How are they similar? Changing the extracellular Na+ concentration does not significantly change the membrane potential. Which of the following has the most negative voltage? This phenomenon is known as You correctly answered: wave summation. Your answer: You must increase the frequency of the stimulus stimulus to both to reach.
You correctly answered: all of the above. Which of the following modalities will induce the largest amplitude receptor potential in the Pacinian corpuscle? You correctly answered: As the stimulus frequency increased, the muscle tension generated by each successive stimulus also increased, and a limiting maximum value was observed. Your answer: These are called wave summation, because there is a noted increase in frequency, which resulted in an increased in the force produced by the entire muscle. You correctly answered: Yes, it is greater than the previous stimulations. How well did the results compare with your prediction? You correctly answered: all of the above.
Your answer: moderate-intensity chemical. Your answer: The stimulus modality that induced the largest amplitude receptor potential in the Pacinian corpuscle was high-intensity pressure. Which of the following has the most negative voltage? Your answer: The passive channels that are likely found in the membrane of the olfactory receptor, Pacinian corpuscle, and in the membrane of the free nerve ending are passive ligand-gated potassium channels. In between these modalities, moderate-intensity pressure would induce the largest response, so it compared accurately with my predictions. You correctly answered: Yes, the second twitch generated more muscle force. The amplitude of the response was 25 mV for this modality. If not, how did you achieve an active force of 5? There are voltage-gated Na+ channels all along the axon.
An action potential is a large, all-or-none change in membrane potential. Your answer: The stimulus modality that induced the largest amplitude receptor potential in the olfactory receptors was high-intensity chemical. PhysioEx Lab Report Exercise 3: Neurophysiology of Nerve Impulses Activity 2: Receptor Potential Name: Karime Castillo Date: 29 May 2020 Session ID: session-8522d165-8156-9e52-5f40-c0d99e61ede Pre-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. Why or why not? The membrane has open K+ channels, and changing extracellular K+ concentration results in a change in membrane potential. Does the free nerve ending likely have this isoamylacetate receptor protein? The action potential is an all-or-none event. Are these results called treppe or wave summation? TTX alters the resting membrane potential of all neurons in the lips d. You correctly answered: a change to -50 mV.
Your answer: By the term graded potential, it is meant that they are brief, localized changes to the membrane potential that can be either depolarizing or hyperpolarizing. You correctly answered: a change to -60 mV. Another way to increase the force produced by a muscle is to You correctly answered: increase the number of activated motor units. . All of these answers are correct. You correctly answered: application of higher voltages to the whole muscle. Would the response at R2 after lidocaine application necessarily be zero? You correctly answered: Light-transducing proteins are not present in the Pacinian corpuscle.
Will there be a limit to this response? How well did the results compare with your prediction? You would never get additional action potentials at this intensity. The test only tells us this, so I would need more information before I can confirm that these patients have either type of diabetes. In between these modalities, moderate-intensity pressure would induce the largest response, so it compared accurately with my predictions. Explain how each is achieved in vivo. It is harder to generate a second action potential soon after the first action potential because a. Thus, with a blow to the eye, one "sees stars. Does the Pacinian corpuscle likely have this isoamylacetate receptor protein? Action potentials propagate or remake themselves at each point along the axon.
Patients 3 and 5 are in the diabetic range but I can't say that these patients have these specific types of diabetes since both patients 3 and 5 have high plasma glucose results. The amplitude of the response was 40 mV for this modality. Are these results called treppe or wave summation? How well did the results compare with your prediction? How was each achieved in the experiment? The stimulus had an increased frequency at which it stimulated the muscle fiber. All of these are reasonable explanations. You correctly answered: No.
