Neuromuscular Reflexes Lab Data & Analysis

Thursday, April 24, 2008


Tapping the patellar tendon in the knee caused contraction of the quadriceps muscle and extension of the leg. Results from this are in table 2. There was also a reinforced reflex done, where the subject voluntarily contracted the quadriceps after hearing a tap on the table. These results are in table 1.

As you can see in table 1, the reaction time when hearing a tap on the table to contracting the muscle is much slower than when the patellar tendon is tapped. However, reaction time progressively got better as the tapping and reacting continued. When the tendon was tapped, the reaction times were basically steady. Also, when the tendon was tapped, the muscle contracted only a little. On the other hand, the muscle contracted much more when it was voluntarily tightened. A reflex is faster than this voluntary action because it is uncontrolled and the muscle reacts. When a muscle is voluntarily contracted, your brain has to tell your muscle to tighten after hearing the sound of tap. This is a much longer process, as seen in the tables above.

The pattern of electrical activity leading to contraction of leg muscles was either very drastic or very subtle, depending if it was voluntary or not. The contraction of the heart’s electrical activity is mainly steady, more frequent beats depending on how hard the heart is working, and it is constant. If the muscle in the leg is resting, there is no electrical activity. The heart can’t rest and stop. Also, the electrical activity when the leg is slowly raised looks like a steady curve, where as it is sharper the harder the muscle works when squatting or lifting the leg.

Thursday, April 24, 2008
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