EMG Lab

To start off our unit on the Muscular System we had an EMG lab. EMG is a graphical recording of electrical activity within the muscles. When the muscles are activated by nerves it results in changes in ion flow across cell membranes. This generates electrical activity. In this lab we were trying to create a graph that represented the electrical activity of a muscle and how much energy was used when a muscle would contract. So for our experiment we did a chewing activity to evaluate the muscles in the jaw when chewing different types of food.

Hypothesis:

If our group tests the muscles in the jaw while someone chews different foods then the harder foods will make the muscles work more and will generate more electrical activity on the graph because your muscles in the jaw work harder to chew harder foods then they do to chew softer foods.

Materials:

Eater (to eat the different foods)

Different types of food

EKG probe and electrode tabs

Experiment:

After setting up the computer we hooked our "Eater" Sierra up to the probes. We put a probe on her upper jaw and lower jaw. First we set up a baseline by having Sierra clench her jaw 30 seconds. Then we gave Sierra different foods that were varying hardness to chew slowly. Sierra would rest her jaw for 5 seconds then start chewing the food until swallowing. The clenching data was used to compare to the other foods that were chewed. The foods Sierra tried were barbeque chips, a carrot, chocolate chip cookies, a banana, celery, beef jerky, and pudding. We also had her drink Dr. Pepper.

DATA:

Data Analysis:

From the data we collected you can see that the different foods caused higher and lower electrical activity. The clenching of the jaw we used as average jaw activity at 0.5 mV. The food that caused the highest amount of electrical activity was the pudding at 2.2 mV. We think this is because when people chew they normally don't open their mouth very much but when people eat pudding they tend to open their mouth wider. The food that caused the lowest amount of electrical activity was the chocolate chip cookie at 0.3 mV. Along with the cookie the Dr. Pepper also created electrical activity at 0.3 mV. The other foods rated everywhere between these two. The celery came the closest to the baseline at 0.6 mV.

Conclusion:

After our experiment we concluded that our hypothesis was not always true. Foods that are harder tended to make our jaw work harder but it is not always the case. Sometimes the way your mouth chews depends on the texture of the food. Something sticky and creamy like pudding can make your mouth open wider which causes more electrical activity. Our graph and analysis prove this.

Reflection:

I really enjoyed this lab. It was a really good way to start off the muscular system! I liked this lab because it made me think about muscles that I never really think about. I never thought about the jaw working in that way. Our group worked very well together to finish our project. I really enjoyed this lab because of how much fun we had doing it. It was also a good idea to call the lab a "Potluck!" I think our experiment was a great success and a lot of fun!