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2/STRUCTURE AND FUNCTIONS OF CELLS OF THE NERVOUS SYSTEM
TABLE OF CONTENTS
TEACHING OBJECTIVES
KEY TERMS
LECTURE GUIDE
Cells of the Nervous System
Communication Within a Neuron
Communication Between Neurons
FULL CHAPTER RESOURCES
MyPsychLab
The Virtual Brain
Lecture Launchers
Activities
Assignments
Web Links
PowerPoint Presentations
Test Bank
Accessing All Resources
Handout Descriptions
Handouts
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TEACHING OBJECTIVES
After completion of this chapter, the student should be able to:
1. Name and describe the parts of a neuron and explain their functions.
2. Describe the supporting cells of the central and peripheral nervous systems and
describe and explain the importance of the blood–brain barrier.
3. Briefly describe the neural circuitry responsible for a withdrawal reflex and its
inhibition by neurons in the brain.
4. Describe the measurement of the action potential and explain how the balance
between the forces of diffusion and electrostatic pressure is responsible for the
membrane potential.
5. Describe the role of ion channels in action potentials and explain the all-or-none law
and the rate law.
6. Describe the structure of synapses, the release of the neurotransmitter, and the
activation of postsynaptic receptors.
7. Describe postsynaptic potentials: the ionic movements that cause them, the processes
that terminate them, and their integration.
8. Describe the role of autoreceptors and axoaxonic synapses in synaptic communication
and describe the role of neuromodulators and hormones in nonsynaptic communication
▲ Return to Chapter 2: Table of Contents
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2
KEY TERMS
sensory neuron (20)
motor neuron (20)
interneuron (20)
central nervous system (CNS) (21)
peripheral nervous system (PNS) (21)
soma (21)
dendrite (21)
synapse (21)
axon (21)
multipolar neuron (22)
bipolar neuron (22)
unipolar neuron (22)
terminal button (22)
neurotransmitter (22)
membrane (23)
cytoplasm (23)
adenosine triphosphate (ATP) (23)
nucleus (23)
chromosome (23)
deoxyribonucleic acid (DNA) (24)
gene (24)
cytoskeleton (24)
enzyme (24)
axoplasmic transport (24)
microtubule (24)
glia (24)
astrocyte (24)
phagocytosis (25)
oligodendrocyte (25)
myelin sheath (25)
node of Ranvier (25)
microglia (27)
Schwann cell (27)
blood–brain barrier (27)
area postrema (28)
electrode (30)
microelectrode (30)
membrane potential (30)
oscilloscope (31)
resting potential (31)
depolarization (31)
hyperpolarization (31)
action potential (31)
threshold of excitation (31)
diffusion (32)
electrolyte (32)
ion (32)
electrostatic pressure (32)
intracellular fluid (32)
extracellular fluid (32)
sodium-potassium transporter (33)
ion channel (34)
voltage-dependent ion channel (35)
all-or-none law (36)
rate law (36)
saltatory conduction (36)
postsynaptic potential (38)
binding site (38)
ligand (38)
dendritic spine (38)
presynaptic membrane (38)
postsynaptic membrane (38)
synaptic cleft (38)
synaptic vesicle (38)
release zone (39)
postsynaptic receptor (39)
neurotransmitter-dependent ion
channel (39)
ionotropic receptor (40)
metabotropic receptor (40)
G protein (40)
second messenger (40)
excitatory postsynaptic potential
(EPSP) (41)
inhibitory postsynaptic potential
(IPSP) (41)
reuptake (42)
enzymatic deactivation (42)
acetylcholine (ACh) (42)
acetylcholinesterase (AChE) (43)
neural integration (43)
autoreceptor (44)
presynaptic inhibition (44)
presynaptic facilitation (44)
neuromodulator (45)
peptide (45)
hormone (45)
endocrine gland (45)
target cell (45)
▲ Return to Chapter 2: Table of
Contents
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3
LECTURE GUIDE
I. Cells of the Nervous System (text p.21)
Assignments
2.1 Vocabulary Crossword Puzzle
Web Links
2.1 The Story of a Membrane
2.2 Glia the Forgotten Brain Cell
2.3 Millions and Billions of Cells: Types of Neurons
2.4 The Blood Brain Barrier
2.8 Biology Animations
Assignments
2.1 Vocabulary Crossword Puzzle
Handout Descriptions
2.1 Concept Maps
2.6 Things That You Need to Know about Neurons
2.7 How to Murder a Neuron
Handouts
2.1 Concept Maps
2.2 Vocabulary Crossword Puzzle
2.6 Things That You Need to Know about Neurons
2.7 How to Murder a Neuron
A. General organization of the nervous system
1. Types of neurons
a. Sensory neurons detect changes in the internal or external environment
b. Motor neurons control muscular contraction or glandular secretion
c. Interneurons
1. Local
2. Relay
2. Divisions of the nervous system
a. Central nervous system (CNS): the brain and the spinal cord
b. Peripheral nervous system (PNS): the nerves outside the skull and spinal cord and the
sensory organs
B. Neurons
1. Basic structure (Figure 2.1, text p. 22)
a. Soma (cell body)
b. Dendrites
1. Synapse: the junction between the terminal buttons of one neuron and the somatic
or dendritic membrane of the receiving cell
c. Axon
1. Covered with myelin
2. Carries the action potential
d. Classification of neurons (by axons and dendrites leaving the soma)
1. Multipolar (Figure 2.1, text p.22)
2. Bipolar (Figure 2.2, text p.22)
3. Unipolar (Figure 2.2, text p.22)
e. Nerves (Figure 2.3, text p.23)
1. Bundles of axons
f. Terminal buttons and synaptic connections (Figure 2.4, text p.23)
1. Site of neurotransmitter release
2. Internal structure (Figure 2.5, text p.24)
a. Membrane
1. Boundary of cell
2. Contains proteins
b. Cytoplasm
1. Jelly-like fluid containing organelles
2. Contains mitochondria
a. Extract energy from nutrients
b. Synthesize adenosine triphosphate (ATP)
c. Contain their own genetic material
d. Replicate independently of the rest of the cell
c. Nucleus
1. Chromosomes
a. Consist of long strands of DNA
b. Contain genes, which code for proteins
d. Proteins
1. Cytoskeleton
2. Enzymes
3. Microtubules
a. Axoplasmic transport
1. Anterograde: cell to terminals
2. Retrograde: terminals to cells
C. Supporting Cells
1. Glia: in the central nervous system
a. Astrocytes (Figure 2.6, text p.25)
1. Control chemical composition around neurons
2. Processes wrap around neurons and blood vessels
3. Help nourish neurons
a. Convert glucose from bloodstream to lactate, which is then used by neurons
b. Store glycogen
4. Act as “glue”
5. Surround and isolate synapses
6. Remove debris via phagocytosis
b. Oligodendrocytes (Figure 2.7, text p.37)
1. Produce the myelin sheath in the CNS (Figure 2.8, text p. 26)
2. Node of Ranvier: space between beads of myelin
3. One oligodendrocyte produces up to 50 myelin segments
c. Microglia
1. Phagocytes
2. Protect brain from invading organisms – immune system function
2. Schwann Cells – peripheral nervous system
a. Produce myelin in the PNS (Figure 2.8, text p. 26)
1. Each segment of myelin is one Schwann cell
b. Chemical composition of myelin in PNS differs from that of the CNS
D. The Blood–Brain Barrier (Figure 2.9, text p. 28)
1. Ehrlich’s experiment: injected blue dye into the blood; did not dye the CNS
2. Selectively permeable
a. Active transport ferries many molecules into the CNS
3. More permeable in some areas, e.g. area postrema
II. Communication Within A Neuron (text p. 28)\
MyPsychLab
2.1 Simulate: The Action Potential
Lecture Launchers
2.1 Metaphors
2.2 Animations
2.3 Neuron Skits
Activities
2.1 Measurement of the Speed of Axonal Transmission
Assignments
2.1 Vocabulary Crossword Puzzle
Web Links
2.8 Biology Animations
2.9 Resting Membrane Potential
Handout Descriptions
2.3 Neuron Skits: Firing of a Neuron (for Lecture Launcher 2.3)
Handouts
2.2 Vocabulary Crossword Puzzle
2.3 Neuron Skits: Firing of a Neuron (for Lecture Launcher 2.3)
2.5 Name Tags for Skits
A. Neural Communication: An Overview
1. Withdrawal reflex (Figure 2.10, text p.29)
2. Inhibition of the withdrawal reflex (Figure 2.11, text p.30)
B. Measuring Electrical Potentials of Axons
1. Squid giant axon
a. Large enough to work with - diameter is 0.5mm
b. Survives a day or two in a dish of seawater
2. Measuring electrical charge (Figure 2.12, text p.31)
a. Electrode
b. Microelectrode
1. A small electrode
c. Place electrode in the seawater and the microelectrode in the axon (Figure 2.13, text p.
31)
3. Membrane potential
a. Inside relative to outside
b. Resting potential – 70 mV
c. Depolarization
1. Reduction in size of the membrane potential
d. Hyperpolarization
1. Increase in size of the membrane potential
e. Action potential (Figure 2.14, text p.32)
1. Triggered at threshold of excitation
C. The Membrane Potential: Balance of Two Forces (Figure 2.15, text p.33)
1. The force of diffusion
a. Molecules distribute evenly throughout a medium
b. Without barriers, molecules flow from areas of high concentration to areas of low
concentration
2. The force of electrostatic pressure
a. Electrolytes: molecules that split into two parts with opposing charges
b. Ions
1. Cations – positive charge
2. Anions – negative charge
c. Electrostatic pressure – force of attraction/repulsion
1. Opposites charges attract, like charges repels
3. Ions in the extracellular and intracellular fluid (Figure 2.15. text p. 33)
a. Organic anions (A-)
1. Inside cell
2. Unable to pass through membrane
b. Potassium ions (K+)
1. Concentrated inside
2. Diffusion pushes out
3. Electrostatic pushes in
4. Little net movement
c. Chloride ions (Cl-)
1. Concentrated outside
2. Diffusion pushes in
3. Electrostatic pushes out
4. Little net movement
d. Sodium ions (Na+)
1. Concentrated outside
2. Diffusion pushes in
3. Electrostatic pushes in
4. Sodium-potassium transporter (Figure 2.16, text p. 33)
a. Uses energy
b. Two K+ in; three Na+ out
c. Helps keep concentration of Na+ low inside the neuron
d. Membrane relatively impermeable to Na+
D. The Action Potential (MyPsychLab 2.1: Stimulate: The Action Potential)
1. Ion Channels (Figure 2.17, text p. 34)
a. Proteins
b. Form pores through the membrane that permit ions to enter or leave the cell
2. Sequence of events (Figure 2.18, text p.35)
a. At threshold, voltage-dependent Na+ channels open and Na+ enters cell
1. Membrane potential moves from -70mV to +40mV
b. Voltage dependent K+ channels begin to open and K+ leaves the cell
c. Na+ channels close and become refractory at the peak of the action potential
d. K+ continues to leave the cell until the membrane potential nears normal
e. Na+ channels reset
f. Membrane overshoots resting potential but returns to normal as K+ diffuses
E. Conduction of the Action Potential (Figure 2.19, text p. 36; MyPsychLab 2.4: Explore
the Virtual Brain: Neural Conduction)
1. All-or-none law
a. Action potential either occurs, or does not occur
b. Once initiated, it is transmitted to the end of the axon
c. Always the same size (even when axon splits)
2. Rate law (Figure 2.20, text, p.36)
a. Rate of firing is the basic element of information
3. Saltatory conduction (Figure 2.21, text p.37)
a. Action potential moves passively under the myelin
b. Action potential is regenerated at each node of Ranvier
c. Advantages
1. The neuron expends less energy (ATP) to maintain ion balance
2. Faster conduction
III. Communication Between Neurons (Text p.37; MyPsychLab 2.2 Simulate:
Synapses)
MyPsychLab
2.2 Simulate: Synapses
2.3 Simulate: Postsynaptic Potentials
Lecture Launchers
2.2 Animations
2.3 Neuron Skits
Assignments
2.1 Vocabulary Crossword Puzzle
Web Links
2.5 The Synapse
2.6 Synaptic Transmission
2.7 Synaptic Transmission: A Four Step Process
2.8 Biology Animations
2.10 Synaptic Transmission
Handout Descriptions
2.4 Neuron Skits: The Synapse
2.5 Name Tags for Skits
Handouts
2.2 Vocabulary Crossword Puzzle
2.4 Neuron Skits: The Synapse
2.5 Name Tags for Skits
A. Synaptic Transmission
1. The transfer of information from one neuron to another via a synapse
2. Relies on neurotransmitters
a. Produce postsynaptic potentials
b. Attach to receptor at a binding site
c. Ligand is a chemical that attaches to a binding site
d. Neurotransmitters are natural ligands
B. Structure of Synapses
1. Types of synapses (Figure 2.22, text p.38)
a) Axodendritic: on dendrite
b) Axosomatic: on soma
c) Axoaxonic: on axon
2. Structure (Figures 2.23, text p. 39 and Figure 2.24, text p. 40)
a. Presynaptic membrane
b. Postsynaptic membrane
c. Synaptic cleft
d. Synaptic vesicles: contain neurotransmitter
e. Release zone: the location of neurotransmitter release
f. Postsynaptic density: contains receptors and the proteins that hold them in place
C. Release of Neurotransmitter (MyPsychLab 2.2 Simulate: Synapses)
1. Omega-structure (Figure 2.24, text p.40)
a. Omega figures are synaptic vesicles fused with the membrane
D. Activation of Receptors
1. Postsynaptic receptor
2. Neurotransmitter-dependent ion channels
a. Ionotropic receptors (Figure 2.25, text p.40)
1. Ion channel
2. Neurotransmitter binding site
b. Metabotropic receptors (Figure 2.26, text p.41)
1. Close to a G protein
2. Activation of G protein produces second messenger
a. Opens ion channel
b. Biochemical changes in other parts of the cell
c. Turns genes on and off
E. Postsynaptic Potentials (Figure 2.27, text p.41)
1. Excitatory postsynaptic potential (EPSP)
2. Inhibitory postsynaptic potential (IPSP)
F. Termination of Postsynaptic Potentials
1. Reuptake (Figure 2.28, text p. 32)
2. Enzymatic deactivation
a. Acetylcholine (ACh) by acetylcholinesterase (AChE)
b. Myasthenia gravis
1. Muscular weakness
2. Physotigmine
a. Inhibits AChE
b. Treats symptoms of Myasthenia gravis
3. Caused by immune system attacking ACh receptors
G. Effects of Postsynaptic Potentials: Neural Integration (Figure 2.29, text p.43;
MyPsychLab 2.3 Simulate: Postsynaptic Potentials)
1. Combining of multiple signals
2. Performed by axon hillock
3. Neural inhibition does not always lead to behavioral inhibition
H. Autoreceptors
1. Respond to the neurotransmitter released by the neuron that contains them
2. Generally inhibitory
I. Axoaxonic Synapses
1. Alter amount of neurotransmitter released (Figure 2.30, text p. 44)
2. Presynaptic inhibition
3. Presynaptic facilitation
J. Nonsynaptic Chemical Communication
1. Neuromodulators
a. Modify large numbers of neurons near location of release
b. Generally are peptides
2. Hormones
a. Secreted by endocrine glands
b. Distributed via bloodstream
c. Target cells contain receptors for the hormone
▲ Return to Chapter 2: Table of Contents
FULL CHAPTER RESOURCES
MyPsychLab
The Virtual Brain
Lecture Launchers
Activities
Assignments
Web Links
PowerPoint Presentations
Test Bank
Accessing All Resources
Handout Descriptions
Handouts
MyPsychLab
MyPsychLab (www.mypsychlab.com) is an online homework, tutorial, and assessment
program that truly engages students in learning. It helps students better prepare for class,
quizzes, and exams—resulting in better performance in the course. It provides educators a
dynamic set of tools for gauging individual and class performance.
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Customizable – MyPsychLab is customizable. Instructors choose what students’
course looks like. Homework, applications, and more can easily be turned off and off.
Blackboard Single Sign-on - MyPsychLab can be used by itself or linked to any
course management system. Blackboard single sign-on provides deep linking to all New
MyPsychLab resources.
Pearson eText and Chapter Audio – Like the printed text, students can highlight
relevant passages and add notes. The Pearson eText can be accessed through laptops,
iPads, and tablets. Download the free Pearson eText app to use on tablets. Students can
also listen to their text with the Audio eText.
Assignment Calendar & Gradebook – A drag and drop assignment calendar makes
assigning and completing work easy. The automatically graded assessment provides
instant feedback and flows into the gradebook, which can be used in the MyPsychLab or
exported.
Personalized Study Plan – Students’ personalized plans promote better critical
thinking skills. The study plan organizes students’ study needs into sections, such as
Remembering, Understanding, Applying, and Analyzing.
MyPsychLab Margin Icons – Margin icons guide students from their reading
material to relevant videos and simulations.
MyPsychLab Margin Icons – Margin icons in the textbook guide students from their reading
material to relevant videos and simulations.
MyPsychLab Highlights for Chapter 2:
MyPsychLab 2.1: Simulate: The Action Potential
MyPsychLab 2.2: Simulate: Synapses
MyPsychLab 2.3: Simulate: Postsynaptic Potentials
MyPsychLab 2.4: Explore the Virtual Brain: Neural Conduction
Virtual Brain
The new MyPsychLab Brain is an interactive virtual brain designed to help students better
understand neuroanatomy, physiology, and human behavior. Fifteen new modules bring to life
many of the most difficult topics typically covered in the biopsychology course. Every module
includes sections that explore relevant anatomy, physiological animations, and engaging case
studies that bring behavioral neuroscience to life. At the end of each module, students can take
an assessment that will help their measure their understanding. This hands-on experience
engages students and helps make course content and terminology relevant. References
throughout the text direct students to content in MyPsychLab, and a new feature at the end of
each chapter directs students to MyPsychLab Brain modules.
Virtual Brain Module applicable to Chapter 2, Structure and Functions of Cells of
the Nervous System:
 Neural Conduction: This module reveals the key components of the neural
communication system, as well as the processes of electrical intra-neural and chemical
inter-nerual communication. See membrane potentials, synaptic communication, and
neurotransmitters in action in detailed animations.
Lecture Launchers
Lecture Launcher 2.1 Metaphors
Sometimes, it is helpful to take concepts that students are unfamiliar with and place them in
a more familiar context. Remind the students that these are models and may not work the
same as the real thing, but you can get past some cognitive barriers by making connections
to the student’s current experience.
A simplistic (and probably not entirely accurate) explanation
If you are having trouble understanding Excitatory (EPSP) and Inhibitory (IPSP)
Postsynaptic Potentials, you might find these explanations and metaphors helpful. Please
remember that, like our model neuron, the following description is not how things really
work, but it may help you to get a picture of the events that will then allow you to explore the
information in more detail and revise and correct your understanding.
Concentrations of various chemicals in and around the cell.
The postsynaptic membrane has protein receptors in the membrane made of phospholipids
(fat). Each receptor has a shape that fits at least one neurotransmitter molecule.
Imagine a molecule of neurotransmitter floating through the extra cellular space in the
synapse until it reaches one of these receptors. When the neurotransmitter gets close, it fits
into the protein molecule like a key in a lock. This changes the shape of the protein molecule
and sets off a change in the electrical potential of the cell.
If the neurotransmitter is excitatory at that receptor, it will depolarize the cell membrane
(make it more likely to transmit information) around the receptor site. You might think of
this as dropping a stone into a still lake. The ripples move away from the receptor, getting
weaker and weaker. At some point, a ripple will cross the cell body and move down the
axonal hillock. If the receptor is close to the axonal hillock, the ripple will still be strong
when it gets there.
Axonal Hillock
The axonal hillock is a small “hill” at the beginning of the axon. It is here that the decision
is made to "fire.” The cell. The neuron “gun” is fired at the axonal hillock trigger. A small
squeeze on the trigger will not fire the neuron. There will be a point when the trigger moves
far enough to fire the neuron, and like a gun, once fired, it has to be reloaded.
Postsynaptic Receptors
Cells can be seen as a mini version of the world. Just as the cell seems to make decisions
based on multiple inputs, in society we often make decisions based on information from a
number of people.
Imagine the axonal hillock as a meeting of 100 people - - (100 postsynaptic potentials).
1. The meeting is to decide whether to send a message encouraging another group of people
to move to a different building (The goal is not important in this example).
To make a decision, the meeting must have a Quorum of at least 50 people. Out of the people
at the meeting, at least two-thirds must vote in favor of the action (be positive).
2. The meeting room has just a few people wandering around. (The resting potential) More
people show up until there are 57 people in the room. The meeting begins. There is a vote on
sending the message. Forty-five people vote for sending the message (EPSPs) and 12 vote
against sending the message. Since the vote is more than 2/3 in favor, the message is
sent.
3. The meeting room has just a few people wandering around. (The resting potential) More
people show up until there are 45 people in the room. The meeting begins. There is a vote on
sending the message. Forty people vote for sending the message (EPSPs) and five vote
against sending the message. The vote is more than 2/3 in favor but there was not a quorum
(not enough EPSPs) so the message is not sent.
4. The meeting room has just a few people wandering around. (The resting potential) More
people show up until there are 57 people in the room. The meeting begins. There is a vote on
sending the message. Twenty people vote for sending the message (EPSPs) and 37 vote
against sending the message. Since the vote is not more than 2/3 in favor, the message is
not sent.
In these three situations, the number of excitatory and inhibitory potentials that reach the
axonal hillock at the same time will be combined to determine whether or not the cell fires.
Let’s look at several examples of meeting outcomes.
Excitatory versus Inhibitory
Postsynaptic Potential
Excitatory influences
in the nervous system
make things more likely
to happen
Inhibitory influences
in the nervous system
make things less likely
to happen
Presynaptic versus Postsynaptic
Terminal button of the axon
Dendrite or
cell body side
of the synapse
First, let’s look at the terms that discriminate an EPSP from an IPSP, excitatory and
Inhibitory.
Excitatory influences in the nervous system make things more likely to happen.
Inhibitory influences in the nervous system make things less likely to happen.
How does the axonal hillock know how far is far enough to fire the neuron?
Here is another metaphor. It does a little basic math. Addition and subtraction. If the
ripple of potential is excitatory, when it reaches the axonal hillock it will be added to other
excitatory potentials that arrive at about the same time. If the sum of the potentials is great
enough, the axonal hillock will send an action potential down the axon.
If the ripple is inhibitory, it changes the cell potentials by making the cell less likely to fire or
by subtracting from the potentials arriving at about the same time.
In general, the farther away from the axonal hillock the stimulated receptor is – the less of a
depolarization will occur because the postsynaptic potential fades as it moves away from the
receptor.
What about situations where not all the postsynaptic potentials reach the axonal hillock at
exactly the same time?
Which is going to be the most disruptive? (Have the most influence on
communication.)
1. One person talking during a class or 10 people talking during a class at the same time?
2. Ten people distributed over a large classroom and talking during a class or the same ten
people sitting together and talking during a class?
3. Ten people each talking for one minute at different times in a one-hour class, or the same
ten people talking for one minute at the same time?
Each of these represents a different situation at the cell membrane.
If one receptor is stimulated by an excitatory transmitter, it is not likely to create a large
enough change in the neuron potential to cause the cell to fire. Multiple stimulations, even if
at different locations, are more likely to be successful in depolarizing the membrane and
firing the cell.
More is better.
Even if multiple receptors are stimulated; if they are closer together, they have a greater
effect as the depolarization from one enhances that of the others. This is referred to as
spatial summation.
Together is better.
Neurotransmitters take time to float across the synapse. Not all will reach the receptors at
the same time. If it takes too long, the effect of the early neurotransmitters will be almost
gone before the other arrives
Lecture Launcher 2.2 Animations
Since the process of transmission takes place over time, students may be confused while
looking at still diagrams. The Internet is a great place to find animations that focuse on the
level of detail that you wish to emphasize. Projecting these animations during a lecture and
making them available for further examination online can help students to catch on the way
that a potential travels along the neuron and the changes that take place at a single point
over time.
YouTube is an outstanding resource for many animations, although the links tend not to be
particularly stable. It is also imperative to screen the videos before using them in class.
Lecture Launcher 2.3 Neuron Skits
Scientific courses often miss activities that students find both entertaining and useful
learning activities. One of these is “Role Playing.” Choose students who are outgoing and
willing to volunteer to stand in front of the class. Give them the instruction sheets the class
before they will be doing the activity so that they can prepare their character. (Handout 2.2
or 2.3)
Before the next class, have the students come a few minutes early to discuss their
interaction. You may wish to project an image of a synapse at the front of the room or
suggest that class members turn to an appropriate illustration in their text. During the class,
have the students go through the activity. Ask the class to identify the “actors” and pin
appropriate signs on them. Allow the class to act as directors, revising the action. Encourage
discussion of the difference between the model as portrayed by the actors and the
interactions within the nervous system.
Have class members assist in figuring out what each element should do with the actors
following class instructions. Have the actors try literally to interpret what they are being told
to do. (If the class suggests that the neurotransmitter should go through the cell membrane
before the vesicle attaches to it, the vesicle membrane should keep tightly closed - they have
not been told to let go or to merge with the presynaptic membrane - and the presynaptic
membrane should not let the neurotransmitter through.)
When the correct steps have been figured out, have the actors go through the process one or
two times correctly before joining the class.
Handouts
Handout 2.3 Neuron Skits: Firing of a Neuron
Handout 2.4 Neuron Skits: The Synapse
Activities
Activity 2.1 Measurement of the Speed of Axonal Transmission
Equipment
Stopwatch or watch with second hand
Tape Measure (Optional)
Calculator
It would be very difficult to measure the speed of transmission through an axon in a
classroom if a single axon were used, but an estimate of the speed of transmission can be
easily calculated in a class activity, and the larger the class, the better. Scientists often use
multiple measurements of rapidly occurring phenomena and then divide by the number of
measurements.
Begin by having the class estimate the distance that an impulse must travel to go from a
person’s shoulder to the hand on the same side. (Having a tape measure available is useful,
but not necessary.) Multiply this by the number of students in the class. This is the distance
the signal must travel.
Have students stand. (Moving to the outside of the room works best but may not be possible
for a large lecture class.) Each student places his or her right hand on the right shoulder of
the next person. The instructor begins the action by squeezing the shoulder of the first
student in line while keeping track of the time. The students each squeeze the shoulder of the
next person as soon as he or she feels a squeeze. The last person needs to indicate that he or
she has felt the squeeze so that the instructor can stop timing.
You may need to run through the action a few times to get the estimate to stabilize.
Divide the number of seconds from start to finish by the distance and the number of
students to get an estimate of transmission time. (See Rozin & Jonides [1977] and Hamilton
and Knox [1996].)
Activity 2.2 How to Murder a Neuron
An understanding of the fragile nature of a single neuron can be represented by having the
students explore the manner in which a neuron can be damaged. This handout gives some
suggestions in an informal manner. Have the students pair up to decide what could happen
that would result in the different types of neural damage.
Handout
Handout 2.7 How to Murder a Neuron
Assignments
2.1 Vocabulary Crossword Puzzle
Part of the assignment will require that the student knows the terminology used in
describing the nervous system. I have created a crossword puzzle for this assignment.
Crosswords provide cues in the length of the words and in letters determined from easier
clues.
This can be used as an assignment, a test, or an in class activity done in small groups of two
to five students.
See Handout 2.2: Vocabulary Crossword Puzzle
ACROSS
2.
EXOCYTOSIS – the process by which neurotransmitters are
secreted
5.
AXON – the long, thin, cylindrical structure that conveys
information from the soma of a neuron to its terminal buttons
7.
NUCLEUS – a structure of a cell, containing the nucleolus and
chromosomes
12. DNA – deoxyribonucleic acid is commonly referred to as _____
15. UNIPOLAR – a neuron with one axon and many dendrites
attached to its soma is referred to as _____
20. NEUROTRANSMITTER – a chemical that is released by a
terminal button
DOWN
1.
GENE – the functional unit of the chromosome
3.
4.
6.
8.
9.
10.
11.
13.
14.
16.
17.
18.
19.
SYNAPSE – the space between the terminal button of an axon and the
membrane of another neuron
MITOCHONDRIA – an organelle that is responsible for extracting
energy from nutrients
MRNA – a macromolecule that delivers genetic information concerning
the synthesis of a protein from a portion of a chromosome to a ribosome
SOMA – the cell body of a neuron
ENZYME – a molecule that controls a chemical reaction
RANVIER – a naked portion of a myelinated axon is called a node of
_____
CHROMOSOME – a strand of DNA that carries genetic information
CYTOPLASM – the viscous, semiliquid substance contained in the
interior of a cell
RIBOSOME – a cytoplasmic structure that serves as the site of
production of proteins translated from mRNA
LYSOSOME – an organelle that contains enzymes that break down
waste products
MONOPOLAR – a neuron with one divided axon attached to its soma
is referred to as ____
MYELIN – a sheath that surrounds and insulates axons
ATP – a molecule of prime importance to cellular metabolism
Web Links
2.1 The Story of a Membrane
http://www.concord.org/~barbara/workbench_web/unitIII_mini/cf_membranes/about_pores
.html
Structure of the plasma membrane proteins, lipids, and sugars at work in a single pore
2.2 Glia: The Forgotten Brain Cell
http://faculty.washington.edu/chudler/glia.html
2.3 Millions and Billions of Cells: Types of Neurons
http://faculty.washington.edu/chudler/cells.html
2.4 The Blood Brain Barrier
http://faculty.washington.edu/chudler/bbb.html
An intuitive description of the structure and function of the blood brain barrier.
2.5 The Synapse
http://faculty.washington.edu/chudler/synapse.html
2.6 Synaptic Transmission
http://www.youtube.com/user/llkeeley?feature=mhee
A set of animations showing the basics of neurotransmission using the neuromuscular junction
as a model. This also shows the effect of insecticides on the activity of the neuromuscular
junctions.
2.7 Synaptic Transmission: A Four Step Process
http://www.williams.edu/imput/synapse/pages/about.html
Requires QuickTime for Animations
2.8 Biology Animations
http://highered.mcgrawhill.com/sites/0072437316/student_view0/chapter45/animations.html
Chemical Synapse (478.0K)
Membrane-Bound Receptors, G Proteins, and Ca2+ Channels (825.0K)
Voltage Gated Channels and the Action Potential (1276.0K)
Sodium-Potassium Exchange (1103.0K)
Function of the Neuromuscular Junction (699.0K)
Action Potential Propagation in an Unmyelinated Axon (366.0K)
Animations with voiceover
2.9 Resting Membrane Potential
http://bcs.whfreeman.com/thelifewire/content/chp44/4401s.swf
The “step through” function makes this animation particularly useful for lecture.
2.10 Synaptic Transmission
http://bcs.whfreeman.com/thelifewire/content/chp44/4403s.swf
The “step through” function makes this animation particularly useful for lecture.
PowerPoint Presentations
Two sets of standard lecture PowerPoint slides—comprehensive and brief, prepared by Grant
McLaren, Ph.D., Edinboro University of Pennsylvania, are also offered and include detailed
outlines of key points for each chapter supported by selected visuals from the textbook.
Both sets of PowerPoint slides are available for download at the Instructor’s Resource Center
at www.pearsonhighered.com/irc (ISBN 020594034X).
Test Bank
Written by Paul Wellman, Texas A&M University. This resource contains questions that target
key concepts. Each chapter has approximately 100 questions, including multiple choice,
true/false, short answer, and essay—each with an answer justification, page references, difficulty
rating, and type designation. All questions are correlated to both chapter learning objectives and
APA learning objectives. The Test Bank is also available in Pearson MyTest (ISBN 0205940374),
a powerful online assessment software program. Instructors can easily create and print quizzes
and exams as well as author new questions online for maximum flexibility. Both the Test Bank
and MyTest are available online at www.pearsonhighered.com/irc (ISBN 0205940366).
Accessing all Resources for Foundations of Behavioral Neuroscience, Ninth
Edition:
For a list of all student resources available with Foundations of Behavioral Neuroscience,
go to www.mypearsonstore.com, enter the text ISBN (0205940242) and check out the
“Everything That Goes With It” section under the book cover.
For access to the instructor supplements for Foundations of Behavioral Neuroscience,
Ninth Edition, simply go to http://pearsonhighered.com/irc and follow the directions to register
(or log in if you already have a Pearson user name and password).
Once you have registered and your status as an instructor is verified, you will be e-mailed a login
name and password. Use your login name and password to access the catalogue. Click on the
“online catalogue” link, click on “psychology” followed by “introductory psychology” and then
the Carlson Foundations of Behavioral Neuroscience, Ninth Edition text. Under the description
of each supplement is a link that allows you to download and save the supplement to your
desktop.
For technical support for any of your Pearson products, you and your students can contact
http://247.pearsoned.com.
Handout Descriptions
2.1 Concept Maps
These maps may assist students in organizing the material in this chapter. You can make
these maps available to the students or encourage them to construct their own maps.
2.2 Vocabulary Crossword Puzzle
2.3 Neuron Skits: Firing of a Neuron
Script for Student Role Playing Activity (Lecture Launcher 2.3)
2.4 Neuron Skits: The Synapse
Script for Student Role Playing Activity (Lecture Launcher 2.3)
2.5 Name Tags for Skits
Name tags to be used with scripts for Student Role Playing Activity (Lecture Launcher 2.3)
2.6 Things That You Need to Know About Neurons
A few basic facts about neurons
2.7 How to Murder a Neuron
To be used with Activity 2.2
▲ Return to Chapter 2: Table of Contents
Handouts
Handout 2.1: Concept Maps
Name:
Section:
Date:
Handout 2.2: Vocabulary Crossword Puzzle
The Neuron
Do not include spaces when the answer includes more than one word.
Across
2. The process by which neurotransmitters are secreted.
5. The long, thin, cylindrical structure that conveys information from the soma of a
neuron to its terminal buttons.
7. A structure of a cell, containing the nucleolus and chromosomes.
12.
Deoxyribonucleic acid is commonly referred to as:
15.
A neuron with one axon and many dendrites attached to its soma is referred
to as:
20.
A chemical that is released by a terminal button.
Down
1. The functional unit of the chromosome.
3. The space between the terminal button of an axon and the membrane of
another neuron.
4. An organelle that is responsible for extracting energy from nutrients.
6. A macromolecule that delivers genetic information concerning the synthesis of a
protein from a portion of a chromosome to a ribosome.
8. The cell body of a neuron.
9. A molecule that controls a chemical reaction.
10.
A naked portion of a myelinated axon is called a node of:
11.
A strand of DNA that carries genetic information.
13.
The viscous, semiliquid substance contained in the interior of a cell.
14.
A cytoplasmic structure that serves as the site of production of proteins
translated from mRNA.
16.
An organelle that contains enzymes that break down waste products.
17.
A neuron with one divided axon attached to its soma is referred to as:
18.
A sheath that surrounds and insulates axons.
19.
A molecule of prime importance to cellular energy metabolism
Puzzle created with Puzzlemaker at DiscoverySchool.com
Handout 2.3
Neuron Skit: Firing of a Neuron
THE CHARACTERS
The presynaptic membrane on the terminal button (two to four people, arms
outstretched, holding hands.)
The vesicle (three people holding hands on the inside of the presynaptic
membrane)
A molecule of neurotransmitter (inside the circle made by the vesicle arms)
The dendrite (Two people, one hand on each shoulder of “the receptor”)
The receptor (Stands between the dendrite membranes – arms out)
The action potentials for the presynaptic and postsynaptic neurons. (One
at the back of the classroom near one aisle. The second action potential is standing
behind the barrier formed by the receptor and two dendrite membrane sections.)
THE SETTING
The synaptic gap between two neurons
THE ACTION
The action potential
The action potential runs down the aisle (Axon) yelling “Fire! Fire!”
When it reaches the vesicle, it helps the vesicle over to the membrane.
The vesicle
The vesicle opens at one grasped hand, as does the presynaptic membrane. The
vesicle joins hands with the membrane to become part of the presynaptic membrane.
The neurotransmitter
The neurotransmitter wanders out and meanders around, eventually finding the
receptor.
The receptor
The receptor and neurotransmitter grasp hands for a moment.
The receptor turns tells and the other parts of the membrane that something exciting
has happened.
The second action potential
The second action potential moves away from the receptor up the opposite aisle
(axon)
The neurotransmitter
The neurotransmitter lets go and wanders around for a few more moments before
returning to the presynaptic membrane.
The membrane
The membrane opens and the neurotransmitter moves inside
Handout 2.4
Neuron Skit: Synapse
This is a rough guide for the possible interaction between these characters.
Actors should feel free to improvise, and observers should feel free to comment on and
correct the action.
THE CHARACTERS:
Tranella (a neurotransmitter)
Agie Agonist (An agonist)
Auntie Agonist (An antagonist)
Reggie Receptor (one of the postsynaptic receptors in the synapse)
Soma (The cell body – Played by remaining class members)
THE SETTING:
You are in the synapse of a sensory neuron.
THE ACTION
Reggie Receptor and Soma
(Reggie Receptor is hanging out on the postsynaptic membrane. He is bored, waiting
for something stimulating to happen.)
Tranella, Agie, and Auntie Agonist:
(Tranella, Agie, and Auntie Agonist are wandering around the synaptic gap looking
for Reggie.)
Auntie Agonist and Reggie Receptor and Soma
(Auntie Agonist finds Reggie first. They grasp hands. She begins telling him that
there is nothing of any importance going on and that he doesn’t need to do anything.
She should be as “antagonistic” as possible.)
Auntie wanders off, to be replaced by Agie.
Agie and Reggie Receptor and Soma
(Agie Tells Reggie about what is going on around him, but she waits for a moment or
two before she comments on what she sees most of the time. He passes on the
information to the waiting cell body -- The class).
Agie leaves, and Tranella moves closer to Reggie
Tranella and Reggie Receptor and Soma
(Tranella tells him about things that she is aware of and he passes the information on
to Soma.)
Tranella
(a neurotransmitter)
37
Agie Agonist
(An agonist)
Auntie
Agonist
(An antagonist)
Reggie
Receptor
(a postsynaptic
receptor)
Presynaptic
Membrane
on the
terminal
button
Vesicle
membrane
A molecule of
neurotransmitter
Dendrite
Membrane
The Receptor
The Action
Potential
Handout 2.6
Things That You Need to Know About Neurons.
Water and Ions
The body is 2/3 water.
Water molecules tend to be more positive on one side and negative on the other.
Ions are repelled by the charged sides of water. (Making them hydrophobic)
A small percentage of water molecules pull apart to form ions (O2 - (2 extra
electrons) H+)
Sodium Chloride (NaCl) separates to form ions when dissolved in water.
Chemicals in and Around the Cell.
ORGANIC MOLECULES
ION
INTRACELLULAR
EXTRACELLULAR
(Sea Water)
(Blood)
400
10
20
Sodium (Na+)
50
460
440
Chloride (Cl+)
40
540
560
Calcium (Ca2+)
0.1
10
10
Many
Few
Few
Potassium (K+)
Organic Ions - protein, amino acids,
& nucleic acids etc. (anions -)
Amino Group
Carboxylic Acid
Some organic molecules are made up chiefly of carbon and hydrogen arranged in
chains. These are not charged and do not interact with water molecules...
The Cell
Cells are essentially bags of water floating in water.
Phospholipids have a charged phosphorous containing group at one end and can
interact with water (hydrophilic) and the other end cannot (hydrophobic) making
the molecule (amphipathic – likes both).
When exposed to water the molecules line up. (Form a membrane.)
Membranes are 25 to 60% protein.
Proteins are built using RNA as a pattern to link amino acids.
Protein molecules span the thickness of the membrane. They form hydrophilic
channels and pumps. Some are anchored, others float.
Neurons are very small
The membrane of a neuron is so thin that it cannot be seen under a light
microscope. It is thinner than a wavelength of light. Seven nanometers or 10-9
meters.
Each neuron uses a the same neurotransmitter/s at all its synapses
(In most cases)
Transmission speed is dependent on several factors:
1. Size/Diameter of the cell
2. Myelinization
The myelin cells are made up of a large percentage of lipid (fat).
The information flows in only one direction, unless forced.
Transmission changes the electrical difference between the interior
and exterior of the cell.
Transmission is “all-or-nothing”
Vesicles use calcium to merge with the membrane and release intracellular
material to the outside.
(This is also related to how the cell grows.)
The membrane can also pinch in to bring extra cellular material inside. (Cell
retraction)
Handout 2.7
How to Murder a Neuron
TECHNIQUE
WHAT
HAPPENS
ACCOMPLISHED
Reduce Blood
Supply (Ischemia)
Reduce Glucose in
blood
Heart Attack
Arteriosclerosis
Thrombosis or embolism
Starvation
Insulin overdose
Reduce blood
supply
Reduce oxygen
intake through
lungs
Heart Attack
Arteriosclerosis
Thrombosis or embolism
Drowning
Carbon monoxide
poisoning
Squish it
Reduce space
inside of skull
through:
Reduction of skull
capacity
Increase in fluid in
the cerebrospinal
system
Increase amount of
blood inside of
skull
Crush skull
Insert something into
skull that takes up space
Hydrocephaly
Hematoma
Use the skull to stop a
brain that is moving at
high speed
Poison it
Absorb toxins
which destroy
internal structures
Bind to receptor
sites and stimulate
cells till they die
(Neurotoxins)
Heavy Metals
Mercury
Lead
Arsenic
Cut it
Remove axon
Remove dendrites
Remove synapse
remove cell or
groups of cells
Gun shot wound or other
projectile entering brain
or nervous system
Surgery
Infect it
Bacterial infections
Viral infections
Syphilis
Rabies
Mumps
Herpes
Chicken Pox
Mutate it
Genetic Disorders
Down's Syndrome
Huntington's Chorea
Starve it
Suffocate it
NOTES
Cells that are
without oxygen
may release
excessive
glutamate
(See neurotoxins)
Over
stimulate it
Epilepsy
Grand mal seizures
Expose it
Remove myelin
Multiple sclerosis
Amyotrophic lateral
sclerosis
Attack it
Immune Disorders