The Nervous System
Ode To The Brain
http://www.wimp.com/brainautotuned/
Anatomy & Physiology
The Basics:
The nervous system is your body's decision and
communication center.
• The central
nervous system
(CNS) is made of
the brain and the
spinal cord
• The peripheral
nervous system
(PNS) is made of
nerves.
Neurons
• A neuron is a nerve cell that is the basic building block of the
nervous system and are specialized to transmit information
throughout the body.
• Job: communicating information in both chemical and electrical
forms.
• 3 main types:
• 1. Sensory neurons (afferent) carry information from the
sensory receptor cells throughout the body to the brain.
2. Motor neurons (efferent) transmit information from the
brain to the muscles of the body.
3. Interneurons are responsible for communicating
information between different neurons in the body.
We’ll get back to these later…..
Do Now!
1. What are the two main parts of the
nervous system?
2. What “organs” are these two parts made
up of?
3. What is a neuron?
4. What are the 3 different kinds of neurons?
Use the definitions
below to correctly
label this neuron
•
•
•
•
•
•
•
axon - the long extension of a neuron that carries nerve impulses away from the
body of the cell to other neurons.
axon terminals - the hair-like ends of the axon
cell body - the cell body of the neuron; it contains the nucleus (also called the soma)
dendrites - the branching structure of a neuron that receives messages (attached to
the cell body)
myelin sheath - the fatty substance that surrounds and protects some nerve fibers
node of Ranvier - one of the many gaps in the myelin sheath - this is where the
action potential occurs during saltatory conduction along the axon
nucleus - the organelle in the cell body of the neuron that contains the genetic
material of the cell
Schwann's cells - cells that produce myelin - they are located within the myelin
sheath.
Neurons
Neuron Parts:
• Soma: body of the cell (main space; contains nucleus/DNA)
• Dendrites: receive messages from neurons
• Axon: sends messages to other neurons
Anatomy of a nerve
http://www.youtube.com/watch?v=XgIaAs_ONG4&feature=related
Two parts of Nervous system &
Neuron video clip
• The Nervous System:
• http://www.youtube.com/watch?v=xx-f9Y8wjg
The Teenage Brain on NOVA:
http://www.pbs.org/wgbh/pages/frontline/video/flv/generic.html?s=frol02p3
92&continuous=1
How messages are sent and
received
• Neurons send messages
electrochemically. This means that
chemicals cause an electrical signal.
• Chemicals in the body are "electricallycharged" -- when they have an electrical
charge, they are called ions.
Watch Bill Nye’s Greatest Science Discoveries on Neutrotransmitters.
How messages are sent and
received continued
• Resting Membrane Potential : At rest, there is an excess of negative ions
inside the neuron compared to the outside.
•
How messages are sent and received
continued http://www.teachertube.com/vie
wVideo.php?video_id=153535
• Action Potential
• When a message is incoming, the membrane opens at that point, and
positively charged ions flow in.
• This process is repeated along the length of the membrane, creating the
neural impulse that travels down the axon, causing the neuron to fire.
•
• Electrical changes during the action potential.
The incoming message must be above a certain threshold to cause a neuron
to fire. After it fires, the neuron is returned to its resting state. This process
happens very quickly, and within a few thousandths of a second the neuron
is ready to fire again.
Myelin and Nodes of Ranvier
• The axons of the nerve cells are sheathed in
a smooth fatty protein called myelin which
insulates the axon. It considerably increases
the speed that nerve impulses travel along
the axon.
• Without the myelin, the axons would have to
be about one hundred times their volume to
achieve the same speed of nerve
transmissions. The myelin is wrapped
around the axon in many thin layers. The
myelin does not enclose the axon in one
entire sheath, but has gaps at intervals called
the nodes of Ranvier.
What causes the change in
potential to occur?
1.
A stimulus causes the sodium gates (channel) to open
and, because there's more sodium on the outside than
the inside of the membrane, sodium then diffuses rapidly
into the nerve cell.
2. All these positively-charged sodium ions rushing in causes
the membrane potential to become positive (the inside of
the membrane is now positive relative to the outside). The
sodium channels open only briefly, then close again.
3. The potassium channels then open, and, because there is
more potassium inside the membrane than outside,
positively-charged potassium ions diffuse out. As these
positive ions go out, the inside of the membrane once
again becomes negative with respect to the outside.
From One To The Next
• A chemical message (called a neurotransmitter)
passes from the sending neuron to the receiving
neuron.
• The neurotransmitters leave the sending neuron
and enter the space between the sending and
receiving neurons. This space is called the
synapse or synaptic cleft.
• The neurotransmitters then hook up to a receptor
on the receiving neuron to deliver their message.
• Once neurotransmitters have sent their
message, they can be reabsorbed by the
sending neuron in a process called
reuptake.
• Reuptake allows the messengers to be
reused.
•Two of these
neurotransmitters are
serotonin and
norepinephrine
Reuptake of serotonin occurs when some of the serotonin that is passed from
the presynaptic neuron is recycled back into that neuron (see upward arrows
and F). SSRIs (P) block this reuptake by blocking the channels (B) which allow
for this reuptake of the serotonin (C). This increases the amount of serotonin in
the synaptic cleft that can bind with receptors on the postsynaptic terminal.
Antidepressant Meds
• SSRI
•
Low levels of serotonin and norepinephrine in the synapse are associated with
depression and sadness. Some medications used to treat depression work by
increasing the amount of certain neurotransmitters that are available to carry
messages.
•
Antidepressants, such as selective serotonin reuptake inhibitors, or SSRIs,
work by slowing or blocking the sending neuron from taking back the released
serotonin. In that way, more of this chemical is available in the synapse.
The more of this neurotransmitter that is available, the more likely the message is
received, and depression is reduced.
•
• MAO INHIBITORS:
•
The antidepressants known as MAO inhibitors, or MAOIs, affect
neurotransmitters differently. Monoamine oxidase (MAO) is a natural enzyme that
breaks down neurotransmitters. The drug MAOI disrupts the action of the
enzyme MAO. In that way, there is an increase in the amount of
neurotransmitters in the synapse, making more messengers available to the
receiving neuron, and thus reducing depression.
Neuron parts
http://garyfisk.com/anim/neuronparts.swf
Animated visual:
http://www.classzone.com/cz/books/bio_0
7/get_chapter_group.htm?cin=9&rg=anim
ated_biology&at=animated_biology&var=a
nimated_biology
Quiz Time!
Name the …..
1. Part of the neuron that releases neurotransmitters
into the synaptic cleft.
2. Fatty material that surrounds some axons.
3. Part that takes information away from the cell body.
4. The gaps in the myelin sheath.
5. Part of neuron that contains the nucleus.
6. Part that takes information to the cell body.
7. Organelle in neuron that contains genetic material.
Answers are:
1. Axon terminal
4. Nodes of Ranvier
2. Myelin
5. Soma
3. Axon
6. Dendrites
7. Nucleus
The Central Nervous System
Interesting Facts!
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young frankenstein part 1
The central nervous system is divided into two parts:
the brain and the spinal cord.
The average adult human brain weighs 1.3 to 1.4 kg
(approximately 3 pounds).
The brain contains about 100 billion nerve cells
(neurons) and trillions of "support cells" called gila.
The spinal cord is about 43 cm long in adult women and
45 cm long in adult men and weighs about 35-40 grams.
The vertebral column, the collection of bones (back
bone) that houses the spinal cord, is about 70 cm long.
Therefore, the spinal cord is much shorter than the
vertebral column.
The Brain: The Inside Story: http://watch.thirteen.org/video/1896942975/
The CNS: The Brain
• The cerebrum -- which is just Latin for "brain" -- is the
newest (evolutionarily) and largest part of the brain as
a whole. It is here that things like perception,
imagination, thought, judgment, and decision occur.
• The surface of the cerebrum -- the cerebral cortex -- is
composed of six thin layers of neurons (nerve cells) and is
refered to as the grey matter. It sits on top of a large
collection of white matter pathways.
• The cortex is heavily convoluted with “ridges” called gyri
and “valleys” called sulci. If you were to spread the
cortex out, it would actually take up about 2 1/2 square
feet (2500 sq cm). It includes about 10 billion neurons,
with about 50 trillion synapses!
• The cerebral cortex is divided into four sections, called
"lobes": the frontal lobe, parietal lobe, occipital lobe, and
temporal lobe.
•
The Brain
The cerebral
cortex is
comprised of
the:
frontal lobe,
parietal lobe,
occipital lobe,
and temporal
lobe.
What do each of these lobes do?
• Frontal Lobe- associated with reasoning,
planning, parts of speech, movement,
emotions, and problem solving
Functions associated with the frontal lobes:
Conscious thought
Concentration
Perseverance
Judgment
Attention span
Impulse control - self monitoring and
supervision
Problem solving
Organization
Critical thinking
Forward thinking
Ability to feel and express emotions
Empathy
YouTube - NEURONS AND
NEURO-TRANSMITTERS
What do each of these lobes do?
• Frontal Lobe- associated with reasoning,
planning, parts of speech, movement,
emotions, and problem solving
• Parietal Lobe- associated with movement,
orientation, recognition, perception of stimuli
Parietal Lobe
• The parietal lobes can
be divided into two
functional regions.
• One involves
sensation and
perception and the
other is concerned with
integrating sensory
input, primarily with the
visual system.
What do each of these lobes do?
• Frontal Lobe- associated with reasoning,
planning, parts of speech, movement,
emotions, and problem solving
• Parietal Lobe- associated with movement,
orientation, recognition, perception of stimuli
• Occipital Lobe- associated with visual
processing
Occipital lobes
• The OC are the center of our
visual perception system.
They are not particularly
vulnerable to injury because
of their location at the back of
the brain, although any
significant trauma to the brain
could produce subtle
changes to our visualperceptual system, such as
visual field defects.
What do each of these lobes do?
• Frontal Lobe- associated with reasoning, planning,
parts of speech, movement, emotions, and problem
solving
• Parietal Lobe- associated with movement,
orientation, recognition, perception of stimuli
• Occipital Lobe- associated with visual processing
• Temporal Lobe- associated with perception and
recognition of auditory stimuli, memory, and speech
The senses of the body (speech, hearing,
feelings, seeing and memory) and control of
the muscles, are part of the grey matter’s
function.
TEMPORAL LOBES: Located at sides of head
above ears, the temporal lobes form the wings of
the soul of our living caduceus.
Functions:
The dominant side is usually the left hand side
and governsHearing ability
Understanding and processing language
Memory acquisition - particularly long term
memory
Some visual perceptions
Categorization of objects.
The no dominant side or right side governsRecognition of facial expressions
Decoding vocal intonation
Rhythm
Music
Visual learning
How your memory works?
http://webus.com/brain/braindomin
ance.htm
Left vs. Right side brain
test
The right hemisphere
controls the left side of the
body, and the left
hemisphere controls the
right side.
• A deep furrow divides
the cerebrum into two
halves, known as the left
and right hemispheres.
Sometimes the right
hemisphere is
associated with creativity
and the left hemispheres
is associated with logic
abilities.
• The corpus callosum is a
bundle of axons which
connects these two
hemispheres.
Do Now!
1. What are the 4 parts of the cerebrum?
2. The convolutions of the cerebrum are comprised of
ridges and valleys. What are the ridges called? The
valleys?
3. What part of the brain is dedicated to visual
perceptions?
4. What part of the brain is associated with reasoning,
planning, parts of speech, movement, emotions, and
problem solving?
5. What part of the brain is associated with movement,
orientation, recognition, perception of stimuli?
6. What part of the brain is associated with perception
and recognition of auditory stimuli, memory, and
speech?
7. What is the deep furrow that divides the cerebrum into two
halves known as?
The Cerebellum
The cerebellum, or "little
brain", is similar to the
cerebrum in that it has
two hemispheres and
has a highly folded
surface or cortex.
CEREBELLUM: Located at the base of the skull, and attached to the
rear of the brain stem.
Functions:
Coordination of voluntary movement
posture
Balance and equilibrium
Some memory for reflex motor acts.
Limbic System:
•
•
The limbic system, often referred to as the "emotional
brain", is found buried within the cerebrum. Like the
cerebellum, evolutionarily the structure is rather old.
This system contains the:
1. thalamus (almost all sensory information enters this structure
where neurons send that information to the overlying cortex ),
2. hypothalamus (functions including homeostasis, emotion, thirst,
hunger, circadian rhythms, and control of the autonomic nervous
system. In addition, it controls the pituitary )
3. amygdala (memory, emotion, and fear ),
4. hippocampus (important for learning and memory, for converting
short term memory to more permanent memory, and for recalling
spatial relationships in the world about us)
Sense of smell
BRAIN STEM: Located deep in the brain,
leads to spinal cord. Often referred to as
The 'Reptilian' or 'Primitive' Brain. The
majority of the cranial nerves exit from the
brain stem at the pons.
Functions:
Breathing
Heart Rate
Swallowing
Reflexes to seeing and hearing (Startle
Response).
Controls sweating, blood pressure,
digestion, temperature (Autonomic
Nervous System).
Affects level of alertness.
Ability to sleep.
Sense of balance (Vestibular Function).
• Grey matter – closely packed neuron cell bodies (making up
the cerebral cortex) form the grey matter of the brain. The
grey matter includes regions of the brain involved in muscle
control, sensory perceptions, such as seeing and hearing,
memory, emotions and speech.
• White matter – neuronal tissue containing mainly long,
myelinated axons, is known as white matter or the
diencephalon. It makes up the cerebrum. The color comes
from the myelin.
• The nuclei of the white matter are involved in the relay of
sensory information from the rest of the body to the cerebral
cortex, as well as in the regulation of autonomic
(unconscious) functions such as body temperature, heart rate
and blood pressure.
• Certain nuclei within the white matter are involved in the
expression of emotions, the release of hormones from the
pituitary gland, and in the regulation of food and water intake.
These nuclei are generally considered part of the limbic
system.
Brain stem: 3 parts
• Lower animals
have only a
medulla.
• The brain stem
controls the
reflexes and
automatic
functions (heart
rate, blood
pressure), limb
movements and
visceral functions
(digestion,
urination).
•
•
•
•
•
•
•
•
•
•
Corpus callosum
Cerebellum
Pituitary gland
Pons
Medulla
1.
Spinal cord
Frontal
Temporal
Occipital
Parietal
Put answers on back of fill-in page
6.
7.
8.
2.
3.
9.
4.
5.
10.
12 Cranial Nerves
Fissure: any cleft or groove,
normal or otherwise,
especially a deep fold in the
cerebral cortex involving its
entire thickness.
Brains
Wild pig,
dolphin,
human
Chimpanzee
Sheep Brain Dissection
Guide
http://www.wellesley.edu/Biology/Concepts/Html/sheepbrain.html
http://academic.scranton.edu/department/psych/sheep/
Dura mater
Superior ID
After splitting the cerebral
hemispheres
Part 1: Sheep brain dissection
http://www.youtube.com/watch?v=y7gEWzPqm94
Ventral side of
the brain
Part 2: Brain dissection
http://www.youtube.com/watch?
v=jr3qSaUzc6Q
Here's the cerebellum pushed downward to
expose the superior and inferior colliculi and
pineal gland
The Superior
colliculus (2 parts)
and the inferior
colliculus (2 parts)
make up the
corpora
quadrigemina.
They are the
reflex centers
involving hearing
and vision.
The Nerves
The largest nerve in
the body is the
sciatic and it splits
into the common
tibial and fibular
nerves that run down
each leg.
How the
messages
travel
PNS
• As part of the Peripheral Nervous System, nerves reach from
your brain to your face, ears, eyes, nose, and spinal cord... and from
the spinal cord to the rest of your body.
• Motor neurons (motoneurons) carry signals from the central
nervous system to the outer parts (muscles, skin, glands) of your
body.
• Sensory neurons carry signals from the outer parts of your body
(periphery) into the central nervous system.
• Receptors sense the environment (chemicals, light, sound, touch)
and encode this information into electrochemical messages that are
transmitted by sensory neurons.
• Interneurons connect various neurons within the brain and spinal
cord.
Reflex Pathways
• The simplest type of neural pathway is a monosynaptic (single
connection) reflex pathway, like the knee-jerk reflex.
• 1. When the doctor taps the right spot on your knee with a
rubber hammer, receptors send a signal into the spinal cord
through a sensory neuron.
• 2. The sensory neuron passes the message to a motor neuron
that controls your leg muscles. Nerve impulses travel down the
motor neuron and stimulate the appropriate leg muscle to
contract.
• 3. The response is a muscular jerk that happens quickly and
does not involve your brain.
• Humans have lots of hard-wired reflexes like this, but as tasks
become more complex, the pathway "circuitry" gets more
complicated and the brain gets involved.
Revisiting the Knee-Jerk Response
What is the stimulus?
• The hammer hits the tendon.
• The muscle contracts, causing the foot to
jerk upward.
What is the response?
• The muscle contracts, causing
• the foot to jerk upward.
How is the Hammer Tap Detected?
• The muscles in your leg have
stretch receptors.
• They react to a change in length of
the muscle.
• When the hammer hits the tendon
at the knee, it
• makes a muscle in the front of your
thigh longer
• (stretches it).
• That stimulates the stretch
receptors in that muscle.
Other Reflexes:
Stimulus
An insect flying towards your
eye
Response
Blinking
The aroma of your favorite food Salivation
A bright light shining in your
eye
Pupils get smaller
A nasty odor
Nausea
What’s a Reflex?
• You need to detect a change in the
environment (a stimulus) and react to the
change (a response) in a way that
maintains homeostasis.
• When you do this without thinking, it is
called a reflex.
How is a Stimulus Detected?
• Some cells are specialized to react to a
specific stimulus.
• These are called receptors (they receive
a stimulus). The receptor cells of your
eyes are stimulated by light.
The Response
• When the receptor is stimulated, it sends a
message to a part of your body that effects
the correct response.
• This is called the effector.
Reflex
arc
How the Message Travels From the
Receptor to the Effector.
• A sensory neuron carries the message from the
receptor to the central nervous system (the spinal
cord and brain).
• A motor neuron carries the message from the
central nervous system to the effector.
• This is a reflex arc.
Motor (efferent) Neurons
• Is divided into two groups:
– 1. Autonomic system
– The ANS In most situations, we
are unaware of the workings of
the ANS because it functions in
an involuntary, reflexive manner.
2. Somatic system (back to this in a
moment)
Name the Neurons
• Neuron 2 ?
• Sensory (Afferent) Neuron
Name the Neurons
• Neuron 3 ?
• Interneuron
Name the Neurons
• Neuron 4 ?
• Motor (Efferent) Neuron
The ANS is most important in two
situations:
1.In emergencies that cause stress and require us to
"fight" or take "flight" (run away)
2.In non-emergencies that allow us to "rest" & "digest."
The ANS is divided into three parts:
1. The sympathetic nervous system
2. The parasympathetic nervous system
3. The enteric nervous system (is a meshwork of
nerve fibers that innervate the viscera (gastrointestinal
tract, pancreas, and gall bladder).
.
ANS •
• Sympathetic:
• These are "Fight or
Flight" responses. In
these types of situations,
your sympathetic nervous
system is called into
action - it uses energy your blood pressure
increases, your heart
beats faster, and
digestion slows down.
Parasympathetic
• This calls for "Rest and
Digest" responses. Now
is the time for the
parasympathetic nervous
to work to save energy your blood pressure
decreases, your heart
beats slower, and
digestion can start.
The Autonomic Nervous System
Structure
Sympathetic Stimulation
Parasympathetic Stimulation
Iris (eye muscle)
Pupil dilation
Pupil constriction
Salivary Glands
Saliva production reduced
Saliva production increased
Oral/Nasal
Mucosa
Mucus production reduced
Mucus production increased
Heart
Heart rate and force
increased
Heart rate and force decreased
Lung
Bronchial muscle relaxed
Bronchial muscle contracted
Stomach
Peristalsis reduced
Gastric juice secreted; motility
increased
Small Intestine
Motility reduced
Digestion increased
Large Intestine
Motility reduced
Secretions and motility increased
Liver
Increased conversion of
glycogen to glucose
Kidney
Decreased urine secretion
Adrenal medulla
Norepinephrine and
epinephrine secreted
Bladder
Wall relaxed
Sphincter closed
Increased urine secretion
Wall contracted
Sphincter relaxed
• The inner part, the adrenal
medulla, produces
catecholamines, such as
epinephrine.
• Also called adrenaline,
epinephrine increases blood
pressure and heart rate
when the body experiences
stress.
• These hormones are
produced in response to
stressors such as fright,
anger, caffeine, or low blood
sugar. (Epinephrine
injections are often used to
counteract a severe allergic
reaction.)
Detailed epinephrine action
:Fight or Flight:
http://www.youtube.com/wa
tch?v=ejq99wLEMTw&feat
ure=related
Flight or Flight Response Video
• http://www.youtube.com/watch?v=4g25d7
_Afmc&feature=related (from Discovery
Channel: 6 min.)
• Adrenaline Rush: Standing on a cliff:
http://www.youtube.com/watch?v=DplhL6
mJhcQ&feature=related
• Adrenaline Rush: Shark cage:
http://www.youtube.com/watch?v=50dVhd
4dmp8&feature=fvwrel
Back to
The Somatic Nervous System
• Somatic Nervous System
• The somatic nervous system consists of
peripheral nerve fibers that send sensory
information to the central nervous system AND
motor nerve fibers that project to skeletal
muscle.
• The picture shows the somatic motor system.
The cell body is located in either the brain or
spinal cord and projects directly to a skeletal
muscle.
This very strange
creature in the
Glasgow Science
Centre is the
Homunculus. The
different parts of
the body are sized
according to the
amount of nerves
present in that part
of the body.
Alzheimer’s disease:
• progressive degenerative
brain disease that results
in dementia associated
with a shortage of
acetylcholine (an
important
neurotransmitter) and
structural changes in brain
areas involving cognition
and memory. Because
nerve cells do not
undergo mitosis, new cells
can not be generated.
Cerebrovascular accident (CVA):
• brain dysfunction
where blood
supply to a
region is blocked
and vital brain
tissues dies as
by a blood clot
or ruptured
blood vessel.
This is more
commonly called
a stroke.
http://www.webmd.com/stroke/ss/slideshow-strokeoverview?ecd=wnl_chl_100411
Stroke Test: Talk, Wave, Smile
• The F.A.S.T. test helps spot symptoms. It
stands for:
• Face. Ask for a smile. Does one side droop?
• Arms. When raised, does one side drift
down?
• Speech. Can the person repeat a simple
sentence? Does he or she have trouble or
slur words?
• Time. Time is critical. Call 911 immediately if
any symptoms are present.
Parkinson’s Disease
• Parkinson disease (PD) is characterized
by a slowing of voluntary movements,
bradykinesia “stone face”, muscular rigidity
and tremor at rest.
• These abnormalities result from a
reduction of neurons that make dopamine.
Multiple sclerosis:
• when the myelin
sheath around
the axon
deteriorates the
electrical current
is short circuited.
• The person may
experience visual
and speech
disturbances and
also lose muscle
control.
M.S.
Tourette Syndrome
• This syndrome begins in childhood and manifests itself
through various forms of tics.
• These tics include frequent, irregular movements of the
head, neck, or shoulders. They also may be more
complex motor behaviors such as snorting, sniffing, and
involuntary vocalization.
• As the syndrome progresses repetitive behaviors such
as touching others, obsessive compulsive symptoms,
and explosive involuntary cursing can be more common.
• Aggressive behavior and improper sexual impulses are
the rarest and most severe expressions of the
syndrome.
• The cause of Tourette syndrome is not known, but it is
believed to have a genetic component.
Famous People with Tourettes
(OCD)
Dan Ackroyd was
diagnosed with tourette's
and asperger syndromes
at an early age, but the
symptoms seem to have Wolfgang Amadeus Mozart
disappeared when he was - (1756-1791) It has also
documented that he
around 14. The diagnosis been
was hyperactive, suffered
of Asperger syndrome did from mood swings, had
tics, and loved made-up
not exist in the 1960s,
words. Despite these
when Aykroyd was a
behaviors, we will probably
preteen. It involved mostly never know for certain
grunting and physical tics whether Mozart had TS.
through nervousness.
David suffers from OCD and it
manifests itself through
constant cleanliness and
perfection of all that is around
him. Anything out of order is
enough to cause a conflict and
must be attended to immediately.
Examples of this complete order
is that everything must be in
pairs, if there are three books on
a table one must be added, or
one must be removed. Only 2%
of the population suffer from this
strong OCD.
Cerebral Edema
• The brain reacts to severe head trauma by
retaining water. As a result, the brain swells.
The pressure grows as the brain presses on
the skull. This can be fatal or result in
severe brain damage.
Famous People with Cerebral
Edema
Actor Natasha Richardson
Video: The Secret Mind
54 min
• http://video.google.com/videoplay?docid=2
661634191857056612#
Nervous System Test
Complete your study guide to prepare for
the test.
 The test has….
 29 multiple choice (2 pts each)
 6 labeling neuron (2 points each)
 10 fill in the blanks (2 pts each)
 6 label parts of the brain
 100 points
