The Nervous System
Unit 2: Biological Basis of Behavior
Lesson 2
Objectives:
Students will identify the parts and function
of a neuron.
Students will explain how neurons
communicate info from body to brain and
vice versa.
Students will demonstrate reaction time
and discrimination.
Students will diagram the nervous system.
Warm Up:
What are the three types of imaging
techniques used to study the brain?
Building Blocks
 Brain Cells
 Neurons
 100 billion
 Send/receive chemoelectrical signals (200
mph)
 Glial (Glee-all) Cells
 Trillions
 Regenerate
Types of Neurons
 Sensory Neuron
 Afferent
 From senses to brain
 Motor Neuron
 Efferent
 From brain to
muscles/organs.
 Interneuron
 Association
 From one neuron to another.
Parts of the Neuron (Handout)
 Cell body (soma) and nucleus.
 Dendrites
 Axon and Myelin Sheath
 End bulbs (Terminals)
 Gray Matter: Darker CNS tissues made up of
neurons’ cell bodies & dendrites
 White Matter: Paler CNS tissues comprised of
myelin-sheathed nerve fibers
Neuron Communication
All-or-none response, if nerve
impulse fires (reaches
threshold) it will finish!
 Neurotransmitter
 Chemical that transmits
impulse from neuron to
neuron
 Excitatory- cause next
neuron to fire
 Inhibitory- prevent next
neuron from firing
 Reuptake – if not accepted,
reabsorbed into sending “buttons”
STOP! Review! Think…Don’t Write!
Neurons are brain cells that send and
receive messages…
in form of electrical impulses and
neurotransmitters that bridge synaptic
gaps…
gaps are present to control/monitor activity
by exciting or inhibiting next neuron…
Questions?
Reaction Time
 Time it takes for a
stimulus to reach the
brain and the brain to
send corresponding
response back to the
area of the stimulus
Reaction Time Demo - Rulers
 Working in pairs, have one student place their
arm across a desk with their hand projecting
over the edge. Make sure to have the thumb
and index finger separated by 1.5 inches. The
other students should hold a ruler such that the
lower edge of the ruler is even with the upper
margin of the thumb and index finger. The
second student should drop the ruler while the
first student should try to catch the ruler by
closing the thumb and finger. The first student
should make sure not to move their hand…
Reaction Time Demo - Rulers
Think-Pair-Share
Why is it so difficult to catch the ruler?
Explain in terms of the rate at which the
nerve impulses travel along the nerves.
Effect of Discrimination on Reaction Time
Discrimination
 Distinguishing between
stimuli…more stimuli,
longer reaction time
 Deck of cards example
 Rows (shoulders)
example
Effect of Discrimination on Reaction Time
 Deal a full deck into 1 pile as rapidly as
possible. Time?
 Deal a full deck of cards into 2 piles; one
black, one red. Time?
 Difference in time between above? This
period of time measures the effect of the
neural processes involved in
discrimination.
 Shuffle. Deal a full deck into 4 individual
piles; hearts, spade, clubs, diamonds.
Time? Why is there a difference from
previous times?
 Shuffle and repeat above. Time? Is
there any evidence of training?
Neuroanatomy: Structure of the N.S.
 Peripheral Nervous
System
 Central Nervous System
 Spinal Cord
 43 pair regenerable
nerves connect
sides/parts of body to
CNS
 43-45 cm
 Interneurons
 Transmit messages bodybrain
 Brain
 3lbs
 Neurons & Glial Cells
The Nervous System
Neurons (CNS) and
Nerves (PNS) are the
building blocks of the
nervous system!
Peripheral Nervous System
 Somatic N.S.
 Autonomic N.S.
 Controls voluntary
movements
 Controls involuntary
movements
Walking, writing
, lungs, digestion
Autonomic Nervous System
 Sympathetic N.S.
 Parasympathetic N.S.
 “Fight or flight”
 “Rest & digest”
 Prepares body to
respond to stressful /
emergency situations
 Returns body to
normal functioning,
energy conservation
Closure
How do the CNS and PNS work together
to transmit neural messages?
Homework
 PsychSim 4.0
http://www.worthpublishers.com/kolb/content/psy
chsim/index.htm
 Neural Messages HW