Download THE BRAIN - Dublin City Schools

THE BRAIN
AND THE EFFECTS OF
ALCOHOL AND OTHER DRUGS
THE BRAIN
Command center of your body
Weighs about 3 pounds
Different centers which control
different things
Despite being 90-95 percent of its
adult size by age six, the brain is still
“under construction” until age 18.
BRAIN STEM
Vital life center
Controls breathing, swallowing, heart beat,
sleeping
The things you never think about
Gulping large amounts of alcohol in a short
time can stop the breathing reflex and
cause death
CEREBELLUM
Is responsible for things you learn once
and never have to think about again:
Walking, riding a bike, throwing a ball
Higher thought processes like music and
complex math problems
Changes drastically during teen years,
increasing its number of nerve cells and
connections to the rest of the brain
What Do They Do?
• Frontal Lobe
– Reasoning, planning, parts of speech, movement,
emotions, and problem solving
• Parietal Lobe
– Movement, orientation, recognition, perception
of stimuli
• Occipital Lobe
– Visual processing
Temporal Lobe
– Perception and recognition of auditory stimuli,
memory, and speech
CEREBRAL CORTEX aka
CEREBRUM
Divided into right and left hemispheres
Thinking part of the brain- most highly
developed
Store and process language, math and
strategies
Also contains the LIMBIC SYSTEM
Responsible for survival
Causes you to be hungry for good food and to enjoy
the company of others;
Emotions related to fear, anger and love
LIMBIC SYSTEM
Hippocampus and Amygdala
Memory
• Drugs can have powerful control of the brain
stem and limbic system.
• These systems can override our cortex in
controlling our behavior. So, we do things
without thinking!
Structure of a Neuron
• 5 PARTS
1. Dendrites = receive messages, many
fibers
2. Cell Body = directs all activities of
the neuron
3. Axon = send messages, long single
fiber
4. Myelin Sheath = insulation and speed
of signal transfer
5. Axon Terminals = release
neurotransmitter
MYELIN
A fatty substance that covers axons.
The more myelin an axon has, the faster
nerve impulses can travel.
– After puberty, the amount of myelin in
the brain increases dramatically, making
the brain much more efficient.
NEUROTRANSMISSION =
• The transfer of a message (electrical
impulse “aka” chemical release) from
the axon of one nerve cell to the
dendrites of another
Neurotransmitters
– Chemical messengers carrying
information from one neuron to another
• Types of Neurotransmitters =
– Serotonin (associated with depression)
– Dopamine (associated with depression)
How Neurons Communicate
• Axon terminals release neurotransmitter
(chemical release)
– Neurotransmitters going into the space
between the axon and dendrites called the
synapse.
• Neurotransmitter enters synapse
– Binds to receptors in the dendrites that fit
“Lock & key”