PCA Anatomy Students Study Action Potential in Neurons
By: Brayden Gravley, PCA Junior
The students in Mrs. Allison Pollak’s anatomy class have recently begun studying the complex concept of depolarization and repolarization in cells. Because the process is hard to comprehend without visuals, Mrs. Pollak took her students into the lab for a hands-on activity.
Students were grouped together and given a bag full of the supplies they would need to build their simulation. Various toothpicks symbolized the cell’s membrane and channels leading into the cell. These toothpicks were placed in two rows and certain toothpicks were colored to distinguish between the different channels. The area between the rows of toothpicks represented the inside of the cell. This section was filled with many white beans and few brown beans, showing that there were more K+ ions than Na+ ions inside of the cell. The area above the first row of toothpicks represented what was outside of the cell. This part contained many brown beans (Na+), few white beans (K+), and several phosphates and proteins. Once the set up was complete, the groups were ready to start moving things around to better understand the process.
The sodium channel, or blue toothpick, was “opened” first. One person in the group had fifteen seconds to move as many brown beans as they could into the “cell.” This made a greater number of Na+ within the cell and made the cell itself more positive. Next, the potassium channel, or red toothpick, was opened. Another member of the group had fifteen seconds to move as many white beans out of the cell as they could before their time ran out. Now that the inside of the cell contained less K+, the overall charge of the cell became negative. The next step required both group members to work together. Lastly, the sodium-potassium pump, or yellow toothpick opened. In this step of the repolarization process, the sodium-potassium pump lets two K+ ions come into the cell for every 3 Na+ ions that move out of the cell. One student moved white beans back into the cell as the other student moved brown beans back out of the cell. As soon as this last fifteen seconds was up, the “cell” had returned to its resting potential.
With the cells back at resting potential and the beans cleaned off of the tables, the students returned back to the classroom to review what they learned. Many scientific concepts can sometimes prove difficult to visualize and understand. Mrs. Pollak’s implementation of lab experiments not only enables students a greater understanding of the concepts in which they learn, but also adds an element of fun where their curiosities about the world around them can be explored.
