Neurophysiology of Nerve Impulses
Name _Jasmine Talley________
Lab Time/Date __11/6/13____
Activity 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.
By increasing the extracellular K+ there is efflux and also influx into the cell which increases the tendency of the cell to depolarize.___
2. Explain why increasing extracellular K+ causes the membrane potential to change to a less negative value. How well did the results compare with your prediction? ___
__Potassium ions diffuse out across the membrane, leaving behind a negative net charge._
3. Explain why a change in extracellular Na+ did not alter the membrane potential in the resting neuron. ___
__There are less leakage sodium channels than leakage potassium channels, and more of the potassium channels are open._
4. Discuss the relative permeability of the membrane to Na+ and K+ in a resting neuron. ___
__Membrane permeability to sodium is very low because there are only few sodium leakage channels. Sodium ions do slowly diffuse inward, down their concentration gradient. Left unchecked, such inward leakage of sodium would eventually destroy the resting membrane potential. The small inward sodium leak and outward leak of potassium leak are offset by the sodium potassium pumps._
5. Discuss how a change in Na+ or K+ conductance would affect the resting membrane potential. ___
_The resting period potential is a potential difference between the inside of the cell and the outside of the cell across the membrane. It depends on the resting permeability of the membrane to ions and on the intracellular and extracellular concentrations of those ions to which the membrane is permeable.__
Activity 2 Receptor Potential
1. Sensory neurons have a resting potential based on the efflux of potassium ions (as demonstrated in Activity 1). What passive channels are...