Physio Ex 9.0 Exercsie 3
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. How well did the results compare with your prediction? _______________________________________________________________________
A lesser amount of Potassium ions diffuse out across the membrane, leaving behind a less negative charge. The membrane potential became less negative because less potassium diffused out, so it is more positive (K+) = less negative. ______________
3. Explain why a change in extracellular Na_ did not alter the membrane potential in the resting neuron. __________________________________________________
In a resting neuron, there are fewer sodium leakage channels than potassium leakage 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.
_____________________________________________________________________
Potassium is more permeable than sodium in a resting neuron. Membrane permeability to sodium is very low because there are only a few sodium leakage channels.
5. Discuss how a change in Na_ or K_ conductance would affect the resting membrane potential. ________________________________________________
A change in permeability would affect the intercellular and extracellular concentration of ions during resting membrane potential. The concentration of Na+ and K+ ions inside and outside the cell are the primary factors that produce the resting membrane potential.
A C T I V I T Y 2 Receptor Potential
1. Sensory neurons have a
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. How well did the results compare with your prediction? _______________________________________________________________________
A lesser amount of Potassium ions diffuse out across the membrane, leaving behind a less negative charge. The membrane potential became less negative because less potassium diffused out, so it is more positive (K+) = less negative. ______________
3. Explain why a change in extracellular Na_ did not alter the membrane potential in the resting neuron. __________________________________________________
In a resting neuron, there are fewer sodium leakage channels than potassium leakage 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.
_____________________________________________________________________
Potassium is more permeable than sodium in a resting neuron. Membrane permeability to sodium is very low because there are only a few sodium leakage channels.
5. Discuss how a change in Na_ or K_ conductance would affect the resting membrane potential. ________________________________________________
A change in permeability would affect the intercellular and extracellular concentration of ions during resting membrane potential. The concentration of Na+ and K+ ions inside and outside the cell are the primary factors that produce the resting membrane potential.
A C T I V I T Y 2 Receptor Potential
1. Sensory neurons have a