Transcript Drugs and the Nervous System

Drugs and the Nervous System
Drug: Any substance, other than food, that changes
the structure or function of the body
ALL drugs (prescription, over the counter and illegal) have potential
to do harm if abused or used improperly.
Drugs differ in ways they affect the body. (kill
bacteria, treat disease, affect particular body system)
Some of most powerful drugs cause changes in the
Nervous System (within brain and at synapses
between neurons)
Drugs That Affect the Synapse
Synapse: Key relay station in transmission of
information within N.S.
Neurotransmitters: transmit messages between
neurons or neuron and effector. Drugs that interfere
with actions of neurotransmitters can disrupt the N.S
for better (treatment of disease) or worse (abused or
misused.
Stimulants: Increase actions regulated by N.S
(Ex. increase heart rate, blood pressure,
breathing) and increase release of
neurotransmitters at some synapses in the
brain  feeling of energy and well being.
Effects of stimulants wear off brain’s
neurotransmitters depleted.
User suffers fatigue & depression
Long term use circulatory problems,
hallucinations, depression
Depressants: Decrease rate of functions
regulated by the brain
(Ex. decrease heart rate, blood pressure,
breathing, relax muscles and relieve tension,
anxiety).
Some depressants enhance effects of
neurotransmitters that prevent start of action
potentials. (exhititory/inhibitory compete)
Combination of depressants and alcohol can
depress CNS until breathing stops fatal
Types of Drugs
Cocaine
Opiates
Marijuana
Alcohol
Cocaine: Causes the sudden release in brain
of neurotransmitter dopamine which leads to
intense feelings of satisfaction & pleasure.
Supply of dopamine depleted when drug
wears off  depression  dependence on
cocaine
Cocaine: stimulant that increases heart rate &
blood pressure. Can lead to heart damage or
heart attack
Crack cocaine: potent form of cocaine, highly
addictive because intense high wears off fast.
Cocaine comes from the
South American Coca plant
Opiates: Mimic endorphins, natural
chemicals in the brain that help to
overcome sensations of pain.
1st doses strong feelings of pleasure but
body quickly adjusts to higher levels of
endorphins. Result, body can’t do without
the drug.
When user stops
uncontrollable pain & sickness
because the body can’t
produce enough endorphins.
Marijuana: most widely used illegal drug from
Cannabis sativa (a species of hemp plant).
Hashish (Hash): potent form of marijuana from
flowering parts of the plant.
THC: (Tetrahydrocannabinol) Active Ingredient
Produces temporary feeling of euphoria and
disorientation.
Worse than smoking tobacco for the lungs
Long term use may  memory
loss, inability to concentrate,
decreased testosterone in males.
Alcohol: Depressant that slows down the rate
of CNS function.
Slows down reflexes, disrupts coordination,
impairs judgment.
Pregnant women who drink on a regular basis
risk having a child with Fetal Alcohol Syndrome
(FAS), a group in birth defects caused by effects
of alcohol on the fetus.
FAS babies can suffer heart defects, malformed
faces, delayed growth, poor motor development.
In US >50,000 babies born/year with alcohol related birth
defects, many which are irreversible.
Long term alcohol abuse destroys liver cells
where alcohol is broken down.
Scar tissue develops (cirrhosis) which
eventually blocks flow of blood through the
liver & interferes with liver functions.
Eventually death may
occur from liver
failure.
Liver with cirrhosis
increases in size due
to build up of scar
tissue
Commonly Abused Drugs
Drug Type
Medical Use
Examples
Effects on Body
Stimulants
Increase alertness,
relieve fatigue
Amphetamines
Inc. heart & resp.
rates, elevates BP,
dilates pupils, dec.
appetite
Depressants
Relieve anxiety,
irritability, tension
Barbituates
Tranquelizers
Slows actions of
CNS. Sm
amtscalm, relax
Lg amtsslurred
speech, impaired
judgement
Opiates
Relieve pain
Morphine
Codeine
Depressant.
drowsy, restless,
nausea