Topic 1: It’s My Body
Part 2: Nervous System
Human Organ Systems
Skeletal
Circulatory
Respiratory
Excretory
Nervous
Integumentary
Muscular
Immune
Digestive
Reproductive
Endocrine
How the body response to the changes?
The two organ systems helps body to
adjust to these changes are:
• The nervous systems uses
electrical signal to response to
changes
• The hormonal system also
coordinate some of the body’s
responses, using hormones.
WHAT PARTS DO YOU KNOW THAT ARE
IN THE NERVOUS SYSTEM?

Brain
• Spinal Cord
• Peripheral Nerves
Human Nervous System
Controls and coordinates functions
throughout the body
 Neurons are specialized cells that transmit
impulses throughout the body.
 Nervous System

◦ Central Nervous System
◦ Peripheral Nervous System
 Somatic
 Autonomic
http://www.bbc.co.uk/science/humanbody/body/index.shtml
What makes up the brain, the spinal cord or
your peripheral nerves?
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Neurons are “the cell”
Cell body
Nucleus
Axon
Dendrite
What do you think
surrounds the cell?
What other organelles
would be needed?
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Structure of Neurons
Dendrite
Cell body
Myelin sheath
Axon
Node of Ranvier
Axon
terminals
3 Types of neurons
There are three main types of neurons.
These types are:
sensory neurons,
interneurons, and
motor neurons.
Neurons
Close up look at your synapse (extra notes)
AXON
What is this in
the membrane?
The synapse - where
the action happens
The next cell’s plasma
membrane
Transport
protein
How does the Synapse carry the signal? (extra notes)
1. Electrical current travels down the axon
2. Vesicles with chemicals move toward the membrane - what is
that called?
3. Chemicals are released and diffuse toward the next cell’s
plasma membrane
4. The chemicals open up the transport proteins and allow the
signal to pass to the next cell - what type of diffusion is this?
How the three neurons work together?
Sensory neurons begin with sensory receptors (many different types
of sensory receptors designed to respond to pressure, hot, cold, light,
mechanical vibration, etc. )The impulse is then carried towards the
CNS (Central Nervous System) by a long dendrite to the cell body.
The cell body is found outside of the CNS and the short axon
transmits the impulse to interneurons in the CNS.
Interneurons are located in the CNS Interneurons have many
dendrites and can receive messages from numerous other neurons.
Interneurons organize the numerous signals and relay the appropriate
message to the motor neuron along an axon.
Motor neurons receive signals from an interneuron at a dendrite.
The impulse then travels to the long axon of the motor neuron and on
to an effector. The effector, a muscle or gland, responds to the
stimulus by contracting (muscle) or releasing a hormone or enzyme
(gland).
Synapse

Neurons are not
continuous
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Synapse is “The junction
across which a nerve
impulse passes from an
axon terminal to a neuron,
muscle cell or gland”
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Two types of Synapses:
◦ Excitatory
◦ Inhibitory
Are all neurons equal in size?

Brain vs spinal cord vs peripheral nerves?
About how many neurons are in the human brain?
100 billion
About how many neurons are in the spinal cord?
1 billion
How long do you think the longest axon in the world is?
around 15 feet
How many synapses
are in one neuron?
1,000 to 10,000!!
This science is called Neurobiology
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Looking at the actual cells - how do they work?
Looking at the connections - how and when do they work?
Looking at what can change normal cells and connections
Looking at diseases that occur in the brain
One of the largest areas still unknown
The you that is you is because of your neurons connecting!
What do you think can change
neurons and their connections?
Accidents
 Drugs
 Alcohol
 Disease
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Accidents
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Physical injury of your neurons
Diagram of Human Brain
http://medtropolis.com/virtual-body/
Drugs and alcohol bind important receptors on neurons
Repeated binding causes the neuron to die
Drugs = neuron death
Alcohol damages dendrites - can
repair after abstinence
Alcohol blocks
receptors and
slows down
transmission
•Parkinson's Disease
•ALS - Lou Gehrig’s Disease
•Huntington’s Disease
•Multiple Sclerosis
•Alzheimer's
•Cerebral Palsy
•Epilepsy
•? SIDS
100 Billion or so neurons - what’s the
problem with some of them dying?
•Cells multiply all the time will your neurons?
•Does everyone react the
same way to accidents, or
drugs and alcohol?
•Do all organisms react the
same to all stimulus?
•Which of your activities
use your neurons?
What if
neurons die
here?
or here
or here
or here
or here
Neurobiology Activities and Labs
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What Does Your "Homunculus" Look Like?
(www.accessexcellence.org/AE/AEPC/WWC/1991/homunculus.html)
Effect of Environment on Memory
(http://www.accessexcellence.org/AE/AEC/AEF/1996/brown_memory.
html)
Taste Activity
(http://yucky.kids.discovery.com/flash/fun_n_games/activities/experime
nts/experiment_truly_tasteless.html)
A healthy brain? - Caffeine activity
(http://www.pfizer.com/brain/teachers_html.html)
Pillbug behavior Lab - (http://www.udel.edu/msmith/pillbugs.html)
REFERENCES
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http://faculty.washington.edu/chudler/facts.html
http://occawlonline.pearsoned.com/bookbind/pubbooks/campbell6e_awl/chapter
0/deluxe.html
JOSHSANESPPT.PPT
www.alfamilyties.org/presentations/The%20Neurobiology%20of%20Adole
scent%20Substance%20Abuse%20II.ppt
http://www.nsbri.org/Education/High_Act.html
http://www.pfizer.com/brain/teachers_html.html
http://www.research.buffalo.edu/quarterly/vol10/num01/n1.shtml
http://www.aim-digest.com/gateway/pages/brain/articles/myths.htm
http://www.nida.nih.gov/pubs/teaching/Teaching5/Teaching3.html
http://www.accessexcellence.com/AE/
http://psych.colorado.edu/~kenth/Image14.gif
REFLEX ACTION
What is a Reflex action??
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“An action that is performed without conscious
thought as a response to a stimulus”
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The signals from the receptors do not travel to the brain,
instead they travel through what we call a Reflex Arc.
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Spinal reflexes or Brain Reflexes
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Stimulus – receptor – sensory neuron – association
neuron – motor neuron – Effector - Response
Reflex actions
Try These??
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Draw one reflex arc for your body’s
response to touching a hot object.
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Draw one reflex arc for your body’s
response to standing on something sharp.
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Draw one reflex arc showing your body’s
response to a loud noise.
Try These??
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Draw a stimulus response
model for how the body
would handle a change in
temperature?
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Draw a stimulus response
model for how the body may
respond to a drop in water
concentration?
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Draw a stimulus response
model for how the body may
respond to a drop in sugar
levels?
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Hypothalamus (links
our nervous and
endocrine systems):
◦ Control Metabolic
Activities
◦ Water Balance
◦ Sugar Metabolism
◦ Body Temperature
◦ Hormone Secretion
NERVOUS SYSTEM
REVIEW
1.
Name the Two parts of the nervous system, and
provide there acronyms?
2.
Draw and Label the Key Structures of a Motor
Neuron?
3.
What are the two components of the CNS?
4.
What are the two types of matter that make up
our CNS?
5.
How many Neurons does our brain contain?
6.
Name three parts of the Brain?
7.
How much space does the Cerebrum take in our brain?
8.
What does PNS stand for and what are the two
components?
9.
What are two examples of Receptors?
10.
What function does our Somatic Nervous System play?
11.
What are the two types of Photoreceptors found in the
eye?
12. Apart
from sound, what other function does
our ear play in our body coordination?
13. What
are 3 examples of stimuli our skin can
detect?