Download My Reaction Test Score = Neural Transmission

Biology
Unit 1 – Brain, Background Paper 1-6
Neural Transmission
If our nervous system transmitted messages by electrical impulses we would have instant
reflexes. The signal would travel at near the speed of light. Response time would be nearly
instantaneous. The signals do have an electrical nature and messages can be initiated by electrical
shocks. Rather than moving along a wire like electricity, the signals in your nervous system move by
changing the electrical charge of the
Positive on the outside and negative on the inside
membranes that make up the surface of axons
and dendrites. Ions (electrically charged atoms)
move in and out of the membrane, not along its
length.
The interior of an axon has a resting
potential (electrical charge) that is negative.
The exterior of the axon is positively charged.
Ions flow both in and out of the axon when the
surface membrane of the axon is disturbed by a
Ions flow and change the charges to positive inside
stimulus. This raises the potential of the interior
and negative outside
of the axon to positive. As the interior of the
axon becomes more positively charged it
affects the membrane just next to it and the new
section allows ions to flow across the
membrane. The drawing at the right1 shows the
Change in charges carries the ‘signal’ down the
neuron
action potential as a signal moves down the
axon. This wave of changing electrical charge
flows down the axon until it reaches the terminal button.
At the end (terminal button) of the axon the signal causes small sacks (vesicles) of chemicals
to be released into the space between the end of the axon and the dendrite of the next neuron. These
chemicals (neurotransmitters) travel across the space between the two neurons
(synapse) and cause the next neuron to begin an action potential.
The knee jerk reflex is a monosynaptic response system. This means that the signal
only travels through two neurons and one synapse. It doesn’t even travel as far as the
brain. It only takes about 50 milliseconds (50 thousandths of a second) to complete the
trip from your knee to your spinal cord and back to the thigh muscles.
Go to: http://faculty.washington.edu/chudler/java/dottime.html and test your reaction
time. Record your results in
the data box and paste into
My Reaction Test Score =
your journal.
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Reading 1-6
www-psych.stanford.edu
Name ____________________________ Date ______________ Period ________
Title of Reading: 1-6 Neural Transmission
Points Earned
1 2 3 4 5 6 7
Concept Map of Reading (3 points)
Main Idea
A) What one question do I have about this article?
1 Point
A&B
B) Show or describe the reading to a parent or guardian (Name ___________________).
What comments or questions did they have concerning the reading?
(Biology Homework Time __________)
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Background1-6,Neurotransmission2014.docx
Text 2014
Greg Ballog
Answer
Page 2