Download The Nervous System

The Nervous System:
The Basic Structure
Main Idea: Learning about the nervous
system helps us know how messages
that are sent to the brain cause
behavior.
How the Nervous System Works
Controls emotions, movements,
thinking, and behavior
Two Parts:
– Central Nervous System (the brain and
spinal cord)
– Peripheral Nervous System (the smaller
branches of nerves that reach the other
parts of the body)
Central Nervous System
Brain
Spinal Cord – nerves that run up and
down the length of the back and
transmit most messages between the
body and brain
Peripheral Nervous System
Nerves of the peripheral system
conduct information from the bodily
organs to the central nervous system
and take information back to the
organs.
Peripheral Nervous System
Somatic: controls voluntary muscles
Autonomic: controls involuntary muscles
– Sympathetic: expends energy
Prepares the body for dealing with emergencies or
strenuous activity
Speeds up the heart to hasten the supply of oxygen
and nutrients to body tissue
Increases the blood pressure and suspends some
unneeded activities like digestion.
– Parasympathetic: conserves energy
Works to enhance the body’s ability to recover from
strenuous activity
Reduces heart rate and blood pressure
Neurons
The long, thin cells of nerve tissue
along which messages travel to and
from the brain
Click to explore the parts: http://www.childrenshospital.org/research/_neuron/index.html
Neurons – Basic Parts
Cell Body
– Nucleus
– Produces Energy needed to fuel neuron activity
Dendrites
– short thin fibers that stick out from cell body
– Receive impulses (messages) from other neurons and send them to the cell
body
Axon
– Long fiber that carries the impulses away from the cell body toward the
dendrite of the next neuron
– Can be short or several feet long
Myelin Sheath
– White, fatty substance that insulates and protects the axon
– Speeds the transmission of impulses
– If missing, such as in multiple sclerosis, it can cause erratic and
uncoordinated behavior
Axon Terminals
– Small fibers that branch out at the end of the axon that are positioned
opposite the dendrite of another neuron
Synapse
– Space between the axon terminals of one neuron and the dendrite of another
neuron
– Junction between neurons where the messages are transmitted from one
neuron to the other
Neurotransmitters
Chemicals released to transmit
messages from one neuron to
another
They can excite the next neuron
They can inhibit the message from
traveling to the next neuron
Types of Neurotransmitters
Norepinephrine
– Involved in memory and learning
Endorphin
– Inhibits pain
Acetylcholine
– Involved in memory and movement
Dopamine
– Involved in learning, emotion, arousal, and
movement
Serotonin
Chemical Imbalances
Undersupply
– Acetylcholine = Paralysis and Alzheimer’s
disease
– Dopamine = Parkinson’s disease
– Norepinephrine and Serotonin = Depression
Oversupply
– Dopamine = Schizophrenia