Topic 1: It’s My BodyPart 2: Nervous System

Human Organ Systems

Skeletal MuscularCirculatory ImmuneRespiratory DigestiveExcretory

ReproductiveNervous EndocrineIntegumentary

• The nervous systems uses electrical signal to response to changes

• The hormonal system also coordinate some of the body’s responses, using hormones.

How the body response to the changes? The two organ systems helps

body to adjust to these changes are:

Brain

WHAT PARTS DO YOU KNOW THAT ARE IN THE NERVOUS SYSTEM?

• Spinal Cord

• Peripheral Nerves

Human Nervous SystemControls and coordinates functions

throughout the bodyNeurons 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?Neurons are “the

cell”Cell bodyNucleusAxonDendriteWhat do you think

surrounds the cell?What other

organelles would be needed?

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Structure of Neurons

Dendrite

Axon terminals

Cell body

AxonMyelin sheath

Node of Ranvier

3 Types of neurons

There are three main types of neurons.

These types are: sensory neurons, interneurons, and motor neurons.

Neurons

AXON

The synapse - where the action happens

The next cell’s plasma membrane

What is this in the membrane?

Transport protein

Close up look at your synapse (extra notes)

How does the Synapse carry the signal? (extra notes)

1. Electrical current travels down the axon2. Chemicals are released and diffuse toward

the next cell’s plasma membrane. This allows signals to pass through the synapse to the next neuron

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).

How the three neurons work together?

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

Synapse (extra notes) Neurons are not

continuous

Synapse is “The junction across which a nerve impulse passes from an axon terminal to a neuron, muscle cell or gland”

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

1 billion

around 15 feet

About how many neurons are in the spinal cord?

How long do you think the longest axon in the world is?

How many synapses are in one neuron? 1,000 to 10,000!!

This science is called Neurobiology 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

DrugsAlcoholDisease

Accidents

Physical injury of your neurons

Drugs and alcohol bind important receptors on neurons

Repeated binding causes the neuron to die

Diagram of Human Brain

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

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

REFLEX ACTION

What is a Reflex action?? “An action that is performed without conscious

thought as a response to a stimulus”

The signals from the receptors do not travel to the brain, instead they travel through what we call a Reflex Arc.

Spinal reflexes or Brain Reflexes

Stimulus – receptor – sensory neuron – association neuron – motor neuron – Effector - Response

Reflex arc – how it works? • 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

Reflex actions

Try These??

Draw one reflex arc for your body’s response to touching a hot object.

Draw one reflex arc for your body’s response to standing on something sharp.

Draw one reflex arc showing your body’s response to a loud noise.

Try These??

Hypothalamus (links our nervous and endocrine systems):◦ Control Metabolic

Activities◦ Water Balance◦ Sugar Metabolism◦ Body Temperature◦ Hormone

Secretion

Draw a stimulus response model for how the body would handle a change in temperature?

Draw a stimulus response model for how the body may respond to a drop in water concentration?

Draw a stimulus response model for how the body may respond to a drop in sugar levels?

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?

Neurobiology Activities and Labs 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/experiments/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 http://faculty.washington.edu/chudler/facts.html http://occawlonline.pearsoned.com/bookbind/pubbooks/campbell

6e_awl/chapter0/deluxe.html JOSHSANESPPT.PPT www.alfamilyties.org/presentations/The%20Neurobiology%20of%

20Adolescent%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.h

tm http://www.nida.nih.gov/pubs/teaching/Teaching5/Teaching3.html http://www.accessexcellence.com/AE/ http://psych.colorado.edu/~kenth/Image14.gif