Activity 4: Generation of Action Potentials Name: Instructor: Date: PREDICTIONS 1. Exceeding the threshold depolarization at the trigger zone DECREASES the likelihood of generation of action potential. 2. Action potential amplitude: DOES NOT CHANGE with distance 3. Increasing frequency of stimulation to the trigger zone: DOES NOT increase the production of action potentials. MATERIALS AND METHODS Experiment 1: Effect of Stimulus Strength on Action Potential Generation 1. Dependent Variable
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Activity 4: The Action Potential: Importance of Voltage-Gated Na+ channels Lab Report Pre-lab Quiz Results You have not completed the Pre-lab Quiz. 02/28/15 page 1 Experiment Results You have not completed the Experiment. Experiment Data: 02/28/15 page 2 Post-lab Quiz Results You have not completed the Post-lab Quiz. 02/28/15 page 3 Review Sheet Results 1. What does TTX do to voltage-gated Na+ channels? Your answer: It irreversibly blocks voltage-gated Na+ channels. 2. What does lidocaine
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which cell has the larger resting membrane potential? Explain. If the permeability to K is higher in A than in B‚ then the resting membrane potential (rmp) will be closer to the equilibrium potential in cell A‚ which means the rmp will be more negative in cell A than in cell B; or in other words‚ the potential difference will be LARGER in cell A. 2. Predict the effect of a reduced extracellular concentration of Na+ on the magnitude of the action potential in an electrically excitable cell. If there
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this experiment was to examine how the compound action potentials propagate down the sciatic nerve of a frog based on varying stimuli. Before the nerve could be tested it needed to be extracted from the thigh of the frog and then submerged in saline. Several varying stimuli were used and recorded by a software package. The second experiment requires a constant stimulus with varying reference pin locations. From this the velocity of the action potential propagated can be determined. The experiment revealed
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B1: The permeability of the cell increases enormously during the action potential. Comte Whitney Electricity is vital for neural function and communication. The semi-permeable membrane and presence of charged particles in solution (ions)‚ enables the cell to have control of an electric potential. The cell The concentrations of Na+ and K+ ions upon either side of a cell’s membrane are not equal. In order for the equilibrium to be restored‚ sodium will attempt to enter the cell‚ whilst potassium will
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Resting membrane potentials Definition: Large nerve fibers when not transmitting nerve signals is about 90 millivolt. That is‚ the potential inside the fiber is 90 millivolts more negative than the potential in the extracellular fluid on the outside of the fiber. The Na+-k+ pump also causes large concentration gradients for sodium and potassium across the resting nerve membrane. These gradients are the following: Sodium ( outside): 142 mEq/L Sodium ( inside): 14 mEq/L Potassium ( outside):
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equilibrium potential and use the Nernst equation (see Appendix) to show how the equilibrium potentials for both sodium and potassium are calculated. Equilibrium potential is the potential of the membrane when there is no net flow of ions from one gradient to the other gradient. The ions are equal and are opposite of each other but not moving from one side to the other. Sodium: Ena=2.303((8.31 J m-1 K-1)(310K))/((1(= 9.65 x 104 c m-1))(log(150/15))= 61.54 mV Ek=2.303((8.31 J m-1 K-11)(310K))/((2(= 9
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Abstract This article is investing the effects of speed of the action potential across many neurons through investigating two diseases and performing related lab simulations. Multiple sclerosis and epilepsy are the two disease which are investigated and through the use of Neurons in Action lab simulations‚ we saw the effects that demyelination and channelopathy can have. As my hypothesis guessed‚ demyelination is the main cause of multiple sclerosis and channelopathy is the main cause of epilepsy
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The Nervous System: Membrane Potential 1. Record the intracellular and extracellular concentrations of the following ions (mM/L): Intracellular Extracellular Sodium (Na+) Potassium (K+) Chloride (Cl–) 2. Excitable cells‚ like neurons‚ are more permeable to ___________ than to ___________. 3. How would the following alterations affect the membrane permeability to K+? Use arrows to indicate the change in permeability. a. An increase in the number of passive K+ channels
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2. Considering the nervous system‚ please briefly explain how the electrically excitable membrane changes its electric potential. In other words‚ how is the cell membrane excited? At the surface of the cell membrane‚ there are three classes of gated channels exist‚ chemically gated or ligand-gated channels‚ voltage-gated channels‚ and mechanically gated channels. Originally‚ at the resting membrane potential‚ most of the gated channels are closed. However‚ when these gated channels open‚ the movement
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