Case Study on Membrane Structure and Function

3. Kevin is conscious when certain neurons in his brain are active—they depolarize and undergo action potentials. Describe the process of depolarization of a neuron to threshold.

4. What does Cole mean when he says that anesthesia “inhibits the neurons?”

5. Is Cole correct when he assumes that leak potassium channels are different than voltage-gated potassium channels? Explain your answer.

6. If the anesthesia opens more potassium leak channels, why are Kevin’s neurons less likely to produce action potentials?

7. Suppose Kevin’s pre-op blood work indicates that his extracellular potassium concentration is much higher than usual. This condition is known as hyperkalemia and must be corrected before he can undergo surgery. One of the dangers of hyperkalemia is that it makes neurons and muscle cells more excitable. Why does elevated extracellular potassium have this effect?

8. Similar types of potassium channels are found in skeletal muscle cell (plasma) membranes. Predict the effect of general anesthesia on Kevin’s skeletal muscle contraction during surgery