4 assume the speed of a nerve impulse is 100 ms how

4. Assume the speed of a nerve impulse is 100 m/s. How does this compare to the speed of
electricity in a copper wire (approx. 3.00  10 8 m/s)?
The average speed of a nerve impulse is extremely slower than the speed of electricity in
a copper wire.
5. Compare the average Δ mV of the reflex without reinforcement to the average Δ mV of the
reflex with reinforcement. Which is greater and why?
The average Δ mV of the reflex with reinforcement was greater. This is because the
nerves were already being engaged, and when this happens more signals travel to the
brain and is prepared for more to come. Without the reinforcement, the nerves are not
being activated thus causing a delay when they are stimulated.
Figure 9

14A - 8
Human Physiology with Vernier
Experiment 14A
Reflex – automatic response of a muscle to stimulus
Patellar Reflex – patellar tendon just below the knee
Tap the tendon just below the knee causes a contraction of quadriceps muscle and
extension of the leg
Reflex arc – consists of only two neurons – one sensory neuron and activate one motor neuron
Activates sensory nerve impulses which travel to spinal cord and activate motor neurons
which travel back to the muscle and cause muscle contraction
3 Parts to Lab
1. Voluntary Activation
a. Listen to tap of hammer on table – respond to sound and kick leg
b. Collect 10 kicks and choose best 5 for data
2. Involuntary – Patellar Reflex
a. Measure direct response to reflex – expect to be slightly quicker than voluntary
b. Reflex – automatic response of a muscle to stimulus
c. Patellar Reflex – patellar tendon just below the knee
3. Reflex Reinforcement
a. Measure reflex with reinforcement – expect to be enhanced compared to involuntary
b. Reflex maybe reinforced by voluntary contraction – “spill over” to cause slight activation
of the leg muscle
c. Enhancement of patellar reflex