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?
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Brain
• Spinal Cord
• Peripheral Nerves

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Controls and coordinates functions throughout the body
Neurons are specialized cells that transmit impulses throughout the body.
Nervous System
◦ Central Nervous System (Brain + spinal cord)
◦ 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.

Dendrite
Axon
Cell body
Myelin sheath
Node of Ranvier
Axon terminals

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
The synapse - where the action happens
The next cell’s plasma membrane
What is this in the membrane?
Transport protein

How does the Synapse carry the signal? (extra notes)
1. Electrical current travels down the axon
2. Chemicals are released and diffuse toward the next cell’s plasma membrane. This allows signals to pass through the synapse to the next neuron

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).

https://www.youtube.com/watch?v=p5zFgT4aofA

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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

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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!!

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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!

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Accidents
Drugs
Alcohol
Disease

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Physical injury of your neurons

Drugs and alcohol bind important receptors on neurons

Repeated binding causes the neuron to die

http://medtropolis.com/virtual-body/ http://www.brainline.org/multimedia/interactive_brain/the_human_brain.html
?gclid=CKvFxeiK7LwCFQJrfgodNiQAFw

Drugs = neuron death

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

•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

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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 reactions in humans are controlled by the reflex arc .
• When the safety of an organism demands a very quick response, the signals may be passed directly from a sensory neuron, via a
Interneuron (also known as the relay neurone, to a motor neurone for instant, unthinking action. This is a reflex action .
• A reflex arc is the nerve pathway which makes such a fast, automatic response possible http://www.bbc.co.uk/schools/gcsebitesize/science/add_ocr_21c/brain
_mind/nervoussystemrev3.shtml

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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.

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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

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?

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
)

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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
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 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
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