Reflex Lab

OBJECTIVES: 

• Graph the electrical activity of a muscle activated by a reflex are through nerves to and from the spinal cord.
• Compare the relative speeds of voluntary and reflex muscle activation.
• Associate muscle activity with involuntary activation.
• Observe the effect of central nervous system influence on reflex amplitude.
• Calculate the approximate speed of a nerve impulse.
• Compare reflex response and electrical amplitude in different subjects.

MATERIALS:

• Computer
• Vernier computer interface
• Logger Pro
• Vernier EKG Sensor
• Vernier 25-g Accelerometer
• Electrode tabs
• Reflex hammer
• Cable tie, 10cm long
• Cloth Tape measure
• Pen

PROCEDURE:

In this lab we were testing the reflexes of my knee by hitting the patellar tendon with a reflex hammer. When the muscle is stretched, it activates nerve impulses that travel to the spinal cord. The reflex we tested is mainly a spinal reflex but also signals sent from and to the brain. Down below are the results.

The graph above is reflex number one. This is a regular reflex where the hammer hit the knee. The results of the reflexes are listed below.

• 8.81-8.82= .01 difference
• 10.0-9.99= .01 difference
• 11.36-11.35= .01 difference
• 12.63-12.59= .04 difference

The graph above is reflex run number two. In this run we just hit the knee with the hammer and recorded the results. Listed below are the results.

• .33-.12= 0.21 difference
• 6.97-6.94= .03 difference
• 13.46-13.45= 0.01 difference

The graph above represents voluntary reflex number one. In this run Alexis was hitting the desk with the hammer every now and then and when I heard it hit, I would swing my leg. The results in time difference are listed below.

• 6.89-6.64= .25 difference
• 11.43-11.19= .24 difference
• 15.60-15.49= .11 difference

The graph above shows voluntary reflex number two. The blue represents when the reflex hammer hit the knee and the red represents the reflex of the knee. 

Down below are the differences in each run.

• .50-.30= .20 difference
• 10.22-10.13= .09 difference
• 12.10-11.87= .23 difference
• 15.19-12.18= .01 difference

The graph above is of the tension reflexes. I grabbed one hand with another and tried to pull in each direction. This caused my muscles to be more tense. The results of my reflexes when this happened are listed below.

• 8.85-8.82=.03 difference
• 10.02-10.01=.01 difference
• 11.39-11.38= .01 difference
• 14.01- 13.95= .06 difference