Download Lesson 3 Brain Communication

Brain, Body & Behavior:
Lesson 3:
Brain Communication
Nervous
System:
Brain
Spinal
Cord
Nerves
Remember: Science cannot yet regenerate nerves!
Neurology:
• NEUROLOGY: the branch
of medicine that studies
the disorders of the
nervous system.
• NEUROLOGIST: a
specialist in the study
and treatment of the
disorders of the nervous
system.
• There are approximately
1000 disorders of the
nervous system that are
studied, researched and
treated today.
Jean-Martin Charcot :
“father of neurology”
known for his work on
many neurological
diseases, such as
multiple sclerosis and
ALS.
Neurons:
What is a neuron?
• NEURON: a nerve cell.
• “Neuro” means nerve.
• We have about 100 billion neurons in the
nervous system each having thousands of
connections to other neurons in the
nervous system … perhaps up to a
thousand trillion connections!
Neurons: Electrochemical
Communication:
How does a neuron work?
• Neurons transmit electrical
and chemical information
throughout the brain and the
body.
Neuron Comminucation:
• Neurons communicate with each other in
two (2) ways:
1. ELECTRICAL NERVE IMPULSES:
• A nerve impulse occurs in the form of
biological electricity.
2. CHEMICAL NERVE IMPULSES:
• A nerve impulse occurs when a
neuron is stimulated to fire by
chemicals called neurotransmitters.
Nerve Impulse:
• NERVE IMPULSE: an electrical
and/or chemical message that
travels down a neuron.
• These impulses travel at 120
yards (360 feet) per second.
• Response is almost immediate.
• Ex: movement, sensation.
Parts of a Neuron:
• A typical neuron looks like a tree
with a roots, a trunk and
branches.
Main Parts of a Neuron:
• The roots are
dendrites (receive
signals).
• The trunk of the
neuron is called
the axon.
• The branches are
the axon terminals
(send out signals).
Dendrites:
• Dendrite means “tree.”
• They look like roots of a tree.
• DENDRITES: Short fibers sticking out of a neuron
that work as receptors (receivers) for messages.
• They receive messages from other nerve cells and
send it through the neuron.
• The have DENDRITIC RECEPTORS on the ends:
• Receivers on the end of each dendrite which
catch the chemicals as they jump from the
previous neuron. They then send the message
down the dendrites.
Dendritic
Receptors
Soma:
• SOMA: cell body.
• Holds the NUCLEUS: the cell’s
control center.
• The nucleus stores genetic material.
• The soma provides fuel, manufactures
chemicals, and maintains the entire neuron in
working order.
Soma
Nucleus
Axons:
• AXONS: long fibers that carry messages
away from the soma to another neuron.
• AXON TERMINALS:
• At the end of each axon are axon terminals
(a.k.a “terminal buttons”) sitting opposite the
dendritic receptors of another neuron.
• The ends of axons which connect with
other neurons and release
neurotransmitters into the synapse.
• A message travels from a dendritic
receptor, goes through the soma, and goes
out the axon to another waiting neuron.
Axons
Axon Terminals
Synapse:
• Synapse means “junction
point.”
• SYNAPSE: “junction
point,” or space between
two neurons.
• It is located between the
axon terminal of one
neuron and dendritic
receptor of another.
• The junction point of two
or more neurons where
cell communication takes
place.
• The axon terminal sends
the nerve impulse and the
dendritic receptor
receives the nerve
impulse.
Vesicles:
• VESICLES: Fluid
filled bubble like
containers (sacs)
located at the end of
axons that contain,
burst, and release
neurotransmitters.
Vesicles:
• When the nerve impulse
reaches the axon terminal, the
vesicles spill neurotransmitters
into the synapse which connect
with the dendritic receptor of
another neuron.
Neurotransmitters:
• NEUROTRANSMITTERS: chemicals
that transmit nerve information from
one neuron to another.
• This procedure repeats from neuron
to neuron.
• Sixty (60) known
neurotransmitters???
•Unknown???
Acetylcholine:
• ACETYLCHOLINE:
• Neurotransmitters that
sends information
from one neuron to
another whenever we
move a body part
(makes muscles
contract).
• It also works in
memory.
• ALZHEIMERS DISEASE:
• Low levels of ACH
negatively affect
memory.
• Botulism toxin shuts
off ACH causing
paralysis.
• BOTULISM: a food
poisoning that affects
the nervous system
caused by a bacteria.
• It can be fatal because
it paralyzes the
muscles used in
breathing.
• BOTOX: injections
used to relax facial
muscles and improve
the appearance of
wrinkled skin.
Dopamine:
•
•
DOPAMINE:
neurotransmitter that sends
information from one neuron
to another to move a body
part.
Also involved with
perception, attention and
learning.
Plays a role in addiction.
•
PARKINSONS DISEASE:
•
•
•
•
•
All addictive drugs raise
dopamine levels in the brain.
Low levels of dopamine.
This disease affects the
body’s ability to control
movement.
Characterized by shaking,
tremors, rigidity of limbs,
difficulty speaking, problems
with balance, etc…
• SCHIZOPHRENIA:
• High levels amounts of
dopamine.
• DELUSION:
• A false belief
despite evidence to
the contrary,
usually a symptom
of mental illness.
• HALLUCINATION:
• Sensing things that
are not real.
Serotonin:
• A neurotransmitter that plays a
part in sleep, arousal,
aggression, sensitivity to pain,
sex and the control of appetite
and mood.
• Low levels are associated with
depression.
Endorphins:
• Neurotransmitters that relieve pain
and increase a person’s sense of
well being.
• It is a natural form of morphine made
by the body.
• Endo means “made by the body.”
• Orphin means “morphine.”
• Natural painkillers.
Reuptake:
• REUPTAKE: Neurotransmitters that
are reabsorbed by the same cell that
releases them.
• Ex: SSRI’s: Selective Serotonin
Reuptake Inhibitors:
• Drugs that prevent the reuptake of
serotonin, causing serotonin levels to
increase in the brain, affecting mood.
• Paxil, Prozac, Zoloft, Wellbutrin, etc…
Effects of Drugs on
Neurotransmitters:
• ECSTASY: (MDMA:
methylenodioxymethamp
hetamine)
• AMPHETAMINE:
• Stimulants that heighten
awareness and intensify
feelings of pleasure.
• It increases the heart
rate, blood pressure and
causes the mind to
become more alert.
• Ecstasy stimulates the
brain and increases the
amount of serotonin
released from an axon
terminal across a
synapse to a dendrite
receptor.
• Ecstasy also inhibits the
reuptake of serotonin
back into the axon
terminal that released it.
Effects of Drugs on
Neurotransmitters:
• LSD: (Lysergic Acid
Diethyl amide) a.k.a.
“Acid”
• Hallucinogen:
• A substance that
induces
hallucinations.
• Resembles
neurotransmitters in
their chemical
composition.
• It slows the reuptake
of serotonin.
• Serotonin dendrite
receptors become
overstimulated.
• This causes a flood of
sensory information
that the brain sees as
hallucinations.
The End