Transcript Synapse
Nervous System
Nervous system cells
Neurons
OBJ 43
Glial cells
Types of neurons
sensory neuron
(from senses)
interneuron
(brain & spinal chord)
motor neuron
(to muscle or gland…effector cells)
Human brain
8
4
7
3
2
5
6
1
Divisions of the nervous system
OBJ 40
Nervous System Pathway
How messages travel
BC
A
F
CD
E
D
E
G
B
Synapse
Synapse:
Junction between nerve cells
1st cell releases neurotransmitter to
trigger next cell
synapse
OBJ 45
What are some examples of
neurotransmitters?
Acetylcholine
Epinephrine (adrenaline)
Dopamine
Serotonin
Endorphins
Simplest Nerve Circuit
Reflex arc, or automatic response
signal only goes to
spinal cord
essential actions
don’t need to think or
make decisions about
blinking
balance
pupil dilation
startle
Drugs & the Nervous system
What happens when you interfere
with neural communication?
Nicotine
acts as a stimulant
mimics acetylcholine
triggers the release of dopamine,
making it addictive
Alcohol
Alcohol in drinks is actually ethyl
alcohol
High concentrations can be toxic
Alcohol is a depressant
Excessive amounts of alcohol damages
liver, digestive system, AND NEURONS
Alcohol and teens
Teens’ brains are specially geared for
optimal learning
So, teens experience more severe
damage to brain due to alcohol use
(more blackouts, more brain
damage…smaller brain)
Drug effects
What is going on when someone is addicted
to drugs?
Opiate drugs (heroin, morphine) can mimic
endorphins (a feel-good NT)
Body adjusts to higher amount of endorphinlike chemicals, and can’t do without it
Take more and more of the drug. Without it,
feel pain, nausea, chills, fever, depression
Drug effects
Marijuana (THC) –
THC blocks the action of
neurotransmitters in the brain affecting
motor skills, memory, concentration
Long-term effects: loss of memory,
inability to concentrate, lowered
testosterone
Drug effects
Ecstasy (MDMA)
Causes rush of serotonin
Interferes with homeostasis (temp.)
Feel depressed until body makes
enough of its own serotonin to feel
‘normal’ again
Destroys serotonin neurons axons and
terminals
After exposure to MDMA for 4 days, it
takes more than 7 years for your brain
to recover.
Drug effects
Hallucinogens
LSD
PCP
Interfere with neurotransmitters in brain
Drug effects
Cocaine
Causes dopamine to be released
Not enough is left for normal function,
so users become dependent on it
Even 100 days after a cocaine addict has
stopped using drugs, the decreased metabolism
in the brain's frontal area remains visible. This
region of the brain influences behavior such as
regulating impulsive and repetitive behavior,
planning and organizing activities, and critical
thinking.