Reflexes: Muscle and Reflex Reinforcement

Topics: Muscle, Reflexes, Nervous system Pages: 4 (1329 words) Published: November 15, 2012
I. Contraction of Quadriceps Muscle and Extension of Leg

The purpose of the Patellar reflex lab was to observe the effect of central nervous system influence on reflex amplitude. My hypothesis was a reflex with reinforcement would have a greater Max of (mV). In this lab we attached three electrode tabs to the leg and connected them to a EKG Sensor. Next we swung a reflex hammer in contact with the patellar tendon and observed the results without reinforcement and then with reinforcement. Our results showed that the reflex reinforcement had the highest results over without reinforcement. In conclusion our results showed that focusing on the hammer swing created a lesser reflex, while focusing on another part of the body allowed for a greater reflex. Introduction

In purpose of this lab was to observe the effect of central nervous system influence on reflex amplitude, associate muscle activity with involuntary activation, and obtain graphical representation of electrical activity of a muscle activated by a reflex arc through nerves and form the spinal cord. My hypothesis for this lab was the mV maximum would be with reinforcement. My rationale for my hypothesis was when arms are clenched there will be an increased muscle tone in the rest of your body, therefore on your muscle spindle. The muscle muscle fibers will contract even more due to the spindle fibers already being experienced. When without reinforcement the body anticipated the tap therefore muscle spindle causes the muscle to contract to place resistance from over stretching.

A reflex is an automatic response coordinated within the spinal cord through interconnected sensory neurons, motor neurons, and internuerons. A reflex is a single reflex beginning with a receptor ending at a peripheral effector generally opposes original stimulus. A patellar reflex results from tapping the patellar tendon below the knee with a reflex hammer. This causes contraction of the quadriceps...

References: 1.Atkinson, P., & Atkinson, J. (April, 1996 7). Spinal shock. Retrieved from
2.MSC Web Designs. (n.d.). Testing reflexes redefining spinal shock. Retrieved from
3.Sarikas, S. (2009). Anatomy and physiology. (Second ed.). San Fransisco: Pearson Learning Solutions.
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