380
UNIT THREE
2. Convergence
a. Impulses from two or more axons may converge
on a single postsynaptic neuron.
b. Convergence enables a neuron to sum impulses
from different sources.
3. Divergence
a. Impulses from a presynaptic neuron may reach
several postsynaptic neurons.
b. Divergence ampliF es impulses.
10.8
IMPULSE PROCESSING (PAGE 374)
The way impulses are processed refl ects the organization
of neurons in the brain and spinal cord.
1. Neuronal pools
a. Neurons are organized into pools in the CNS.
b. Each pool receives, processes, and may conduct
impulses away.
c. Each neuron in a pool may receive excitatory and
inhibitory stimuli.
d. A neuron is facilitated when it receives
subthreshold stimuli and becomes more excitable.
10.1 Introduction
1
Describe how the nervous system detects change
associated with the body and reacts to that change to
maintain homeostasis. (p. 354)
2
Distinguish between neurons and neuroglia. (p. 354)
3
Which of the following descriptions is accurate? (p. 354)
a. A neuron has a single dendrite, which sends information.
b. A neuron has a single axon, which sends information.
c. A neuron has many axons, which receive information.
d. A neuron has many dendrites, which send information.
4
Explain the diF
erence between the central nervous system
(CNS) and the peripheral nervous system (PNS). (p. 354)
10.2 General Functions of the Nervous System
5
List three general functions of the nervous system. (p. 355)
6
Distinguish a sensory receptor from an eF
ector. (p. 355)
7
Distinguish between the types of activities that the
somatic and autonomic nervous systems control. (p. 356)
10.3 Description of Cells of the Nervous System
8
Match the part of a neuron on the left with the
description on the right (p. 356):
(1) dendrites
(2)
chromatophilic
substance
(3) axon
(4) cell body
(5) neuro±
brils
A. ±
ne threads in an axon
B.
part of neuron from which
axon and dendrites extend
C.
highly branched, multiple pro-
cesses that may have spines
D. sends nerve impulses
E.
rough endoplasmic reticulum
9
Explain how Schwann cells encase large axons including
the formation of myelin, the neurilemma, and the nodes
of Ranvier. (p. 358)
10
What do Schwann cells and oligodendrocytes have in
common, and how do they diF
er? (p. 358)
11
Distinguish between myelinated and unmyelinated
axons. (p. 358)
10.4 Classi±
cation of Cells of the Nervous System
12
Describe the three types of neurons classi±
ed on the
basis of structure. (p. 360)
13
Describe the three types of neurons classi±
ed on the
basis of function (p. 360)
14
List six functions of neuroglia. (p. 361)
15
Describe the neuroglia of the CNS. (p. 361)
16
Explain how malfunctioning neuroglia can harm health.
(p. 363)
CHAPTER ASSESSMENTS
17
Describe the neuroglia of the PNS. (p. 363)
18
Explain how an injured neuron may regenerate. (p. 364)
10.5 The Synapse
19
The _________
_________ brings the impulse to the
synapse, whereas the __________
_________ on the other
side of the synapse is stimulated or inhibited as a result of
the synaptic transmission. (p. 365)
20
Explain how information is passed from a presynaptic
neuron to a postsynaptic cell. (p. 365)
21
DiF
usion of which of the following ions into the synaptic
knob triggers the release of neurotransmitter? (p. 365)
a. Na
+
b. Ca
+2
c. Cl
d. K
+
10.6 Cell Membrane Potential
22
De±
ne
resting potential.
(p. 366)
23
Distinguish among polarized, hyperpolarized, and
depolarized. (p. 368)
24
Explain why the “trigger zone” of a neuron is named as
such. (p. 368)
25
List in correct order the changes that occur during an
action potential. (p. 368)
26
Explain the relationship between an action potential and
a nerve impulse. (p. 369)
27
De±
ne
refractory period.
(p. 370)
28
Explain the importance of the nodes of Ranvier
and conduction in myelinated ±
bers as opposed to
conduction in unmyelinated ±
bers. (p. 371)
10.7 Synaptic Transmission
29
Distinguish between excitatory and inhibitory
postsynaptic potentials. (p. 371)
30
Explain how enzymes within synaptic clefts and reuptake
of neurotransmitter prevents continuous stimulation of
the postsynaptic cell. (p. 374):
10.8 Impulse Processing
31
Explain what determines the output of a neuronal pool
in terms of input neurons, excitation, and inhibition.
(p. 374)
32
De±
ne
facilitation.
(p. 375)
33
Distinguish between convergence and divergence. (p. 375)
363
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