SVHS ADV BIOLOGY
9th ed. Tortora
NAME: ____________________
PERIOD: 1 2 3 4 5 6
D.R. # 9.3 CONDUCTION OF NERVE IMPULSES AND EVENTS
OF NEURONS AT SYNAPSES
AFTER READING PAGES 259-264 COMPLETE THE FOLLOWING:
1.
Name the ion that moves into the neuron during depolarization. ______________
2. Name the ion that moves out of the neuron during depolarization. _______________
3. Name and describe the type of channel that opens to allow these ions to move in or out.
4. The graph to the right illustrates what occurs during
Figure 9.5
an action potential. Label the following;
X axis and Y axis
Stimulus
Depolarization Phase
Repolarization Phase
After-hyperpolarizing phase
Resting membrane potential
5. Resting potential is _________mV.
6. Threshold has a potential of ________mV.
7. Depolarizing phase reaches _________ mV.
8. Explain what the refractory period is regarding a neuron.
9. Contrast “continuous conduction” with “saltatory conduction” regarding the following: presence of myelin
sheath, location of ion channels, speed of impulse, and size of neurons.
ContinuousSaltatory-
10. Explain why putting ice or a cold pack on an injured area reduces pain.
11. Explain how local anesthetics prevent pain while the dentist or doctor performs a procedure.
12. Diagram a typical chemical synapse to the right with the
following labels;
presynaptic neuron
post synaptic neuron
nerve impulse
Ca2+ and voltage gated channels
Synaptic vesicles
Neurotransmitter
Chemically gated channels
Na+ ions
13. Why does the conduction of the impulse only moves in one direction? (Pre to post neuron)
14. Summarize the events that must occur for an impulse to move from one neuron to a second neuron.
1
2.
3.
4.
5.
6.
7.
9. Describe three ways in which a neurotransmitter is removed from the synapse so that a resting potential can
be created once again.
a.
b.
c.