Understanding Psychology (10th Ed)

E VA LU AT E
1.
The 
is the fundamental element of the nervous 
system.
2.
Neurons receive information through their 
and send messages through their 
.
3.
Just as electrical wires have an outer coating, axons are in-
sulated by a coating called the 
.
4.
The gap between two neurons is bridged by a chemical 
connection called a 
.
5.
Endorphins are one kind of 
, the chemical 
“messengers” between neurons.
R E T H I N K
1.
How might psychologists use drugs that mimic the effects 
of neurotransmitters to treat psychological disorders?
2.
From the perspective of a health care provider: How would 
you explain the placebo effect and the role of endorphins 
to patients who wish to try unproven treatment methods 
that they fi nd on the Web?
Answers to Evaluate Questions
 Module 
7 
Neurons: The Basic Elements of Behavior 
69
1.
neur
on;
2.
dendrites, axons;
3.
myelin sheath;
4.
synapse;
5.
neur
otransmitter
K E Y T E R M S
behavioral neuroscientists 
(or biopsychologists) p. 60
neurons p. 61
dendrite p. 61
axon p. 61
terminal buttons p. 61
myelin sheath p. 62
all-or-none law p. 62
resting state p. 62
action potential p. 63
mirror neurons p. 64
synapse p. 65
neurotransmitters p. 65
excitatory message p. 66
inhibitory message p. 66
reuptake p. 66
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70
In light of the complexity of individual neurons and the neurotransmission process, 
it should come as no surprise that the connections and structures formed by the 
neurons are complicated. Because each neuron can be connected to 80,000 other 
neurons, the total number of possible connections is astonishing. For instance, esti-
mates of the number of neural connections within the brain fall in the neighborhood 
of 10 quadrillion—a 1 followed by 16 zeros—and some experts put the number even 
higher. However, connections among neurons are not the only means of communi-
cation within the body; as we’ll see, the endocrine system, which secretes chemical 
messages that circulate through the blood, also communicates messages that infl u-
ence behavior and many aspects of biological functioning (Kandel, Schwartz, & 
Jessell, 2000; Forlenza & Baum, 2004; Boahen, 2005).
The Nervous System: 
Linking Neurons
Whatever the actual number of neural connections, the human nervous system has 
both logic and elegance. We turn now to a discussion of its basic structures.