NERVOUS SYSTEM OVERVIEW

By: Jason Pha

Nervous System

Central Nervous System

The Central Nervous System consists of the brain and the spinal cord.

The Central Nervous System’s job is to coordinate all parts of the bodies activities.

The spinal cord relays sensory information from the Peripheral Nervous System to the brain.

It also helps as a minor reflex center. The spine also delivers nerve impulses

throughout the body to the muscles. The brain receives inputs from the spinal cord

and also initiates proper motor outputs throughout the body.

Central Nervous System

Peripheral Nervous System

Somatic and Autonomic nervous systems make up the peripheral nervous system.

The PNS is also made of sensory neurons that run from stimulus receptors to inform the CNS of the stimuli.

It also contains motor neurons that run from the CNS to muscles and glands.

Somatic nervous system involves voluntary movement.

Autonomic nervous system involves involuntary movement.

Peripheral Nervous System

Autonomic Nervous System

The Brain

Control center for Nervous System.

Sends signals to all parts of the body for different jobs.

Generates behavioral functions.

Inputs and outputs functions and actions for the body.

Spinal Cord

Long tubular nerve tissue extending from the brain.

Vertebral column protects the nerve cord.

Transmits neural signals between the brain and the body.

Divided into 31 different segments.

Nerves

Nerves carry electrochemical signals throughout the nervous system and between the nervous systems and tissues and organs.

Nerves are divided into 4 classes.

1. Cranial Nerves- connects sense organs to the brain.

2. Central Nerves- connects areas between brain and Spinal cord.

3. Peripheral Nerves- connects spinal cord with limbs.

4. Autonomic Nerves- connects brain and spinal cord with body organs.

Nerve Cells (Neurons)

Specialized cells that conduct electrochemical impulses.

Contains: Dendrite Nucleus Cell Body Axon Axon Terminal Myelin Sheath Schwann Cell

Nerve Cells

Nerve Impulse Movement

When a stimulus is strong enough a nerve impulse is generated.

Chemical and electrical changes occur in the neuron. The cell depolarizes causing an action potential which then

makes the nerve impulse move across the axon. The impulse is passed along to other neurons triggering a

domino effect until the response has been done. A response to the stimuli depends on the type of

neurotransmitters involved. The recovery time or refactory period of a nerve cell takes

0.0004 second to recover after a stimuli has gone through.

Nerve Impulse

Synapses

2 Types: Electrical and Chemical Synapses

Synapses are junctions controlling communication between a neuron and another cell.

Presynaptic cell- transmitting cell

Postsynaptic cell- receiving cell

Synapses

ELECTRICAL SYNAPSES CHEMICAL SYNAPSES

Allows the action potentials to spread directly from presynaptic to the postsynaptic cell.

The cells are connected by gap junctions.

Not as common as chemical synapses in vertebrates and invertebrates.

Electrical signal of the action potential arrives at the synaptic terminal.

Turns into and travels across the synapse and turns back into an electrical signal in the postsynaptic cell.

Interesting Facts

About 13,500,000 neurons can be found in the human spinal cord.

Nervous system transmits messages to the brain at speeds of up to 180 mph.

The spinal cord controls over 10 billion nerve cells, and is less than two feet in length and its diameter is same as that of the index finger.

Website for more interesting facts of the nervous system:

http://www.medindia.net/know_ur_body/nersystem3.asp

Websites

1. Central Nervous System Diagram:http://medicalimages.allrefer.com/large/central-nervous-system.jpg

2. Autonomic Nervous System Diagram:http://www.demosschiropractic.com/illus/autonomic-nervous-system.gif

3. Peripheral Nervous System Diagram:http://visual.merriam-webster.com/images/human-being/anatomy/nervous-system/peripheral-nervous-system.jpg

4. Brain Diagram picture: http://quantumlearningblog.files.wordpress.com/2009/02/brain1.jpg

5. Nervous System Chart Diagram:http://www.mrothery.co.uk/images/Imag78.gif6. Neuron Diagram:

http://training.seer.cancer.gov/module_anatomy/images/illu_neuron.jpg7. Nerve Impulse Diagram:

http://www.freewebs.com/soaring_sphincter_travel_agency/nerve%20impulse.gif

8. Nervous System Video: http://videos.howstuffworks.com/hsw/17120-introduction-to-the-nervous-system-video.htm

9. http://www.garyfisk.com/anim/neuronparts.swf10. Intro to Neurons video:

http://videos.howstuffworks.com/hsw/17067-in-control-introduction-to-neurons-video.htm

Websites

1. Path of a Nerve impulse video: http://www.marymount.k12.ny.us/marynet/stwbwk05/05bio/jsnervous/html/jsanim.html

2. Enteric Nervous system information: http://www.vivo.colostate.edu/hbooks/pathphys/digestion/basics/gi_nervous.html

3. Nervous system and other body systems: http://faculty.washington.edu/chudler/organ.html

4. Nervous System Facts: http://www.medindia.net/know_ur_body/Nersystem2.asp5. Nervous System Worksheet:

http://www.glencoe.com/sec/science/biology/bio2000/chapter/worksheets.php?iRef=36&iChapter=36&iUnit=10&iUnitNumber=10&iArticle=36

6. Chemical Synapse video: http://highered.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sites/dl/free/0072437316/120107/anim0015.swf::Chemical%20Synapse

7. Synapse Picture: http://wpcontent.answers.com/wikipedia/commons/thumb/e/e0/Synapse_Illustration2_tweaked.svg/350px-Synapse_Illustration2_tweaked.svg.png

8. Vocab: http://info.conroeisd.net/~pknowlton/nervocab.htm9. Nerve Cell picture slide 14 in PPT:

http://www.e-radimaging.com/cffm/custom/MS%20May%202008/Figure-2.jpg10. The Neuron Worksheet: http://faculty.washington.edu/chudler/fillin1.html11. Synapses picture slide 19:

http://nobelprize.org/nobel_prizes/medicine/laureates/2000/med-2.jpg