Download Neuron Functioning

Neuron Functioning
KEY TERMS
Types of Neurons
• Sensory Neurons – send signals from
your senses (eyes, ears, nose, taste buds, skin)
toward the spinal cord and brain
• Motor Neurons – send signals from
your brain and spinal cord toward
your body
Reflex Arc
• Interneurons found within the spinal cord
connect sensory and motor neurons creating
an “arc.”
• Signals are rapidly sent along this arc to allow
you to move quickly away from the potentially
dangerous conditions.
The Spinal Cord Handles Reflexes
• No thinking is involved
in a reflex – the brain
does not process the
information until
AFTER the movement
has already occurred.
Absolute Threshold
• An individual neuron will react to stimulation
only if the level of stimulation reaches a
certain trigger point.
• Absolute threshold refers to the minimum
amount of stimulation necessary to cause a
neuron to “fire” a signal.
All-or-Nothing Principle
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A neuron will either send a signal or not.
No such thing as a 27% strength signal.
YES or NO
no such thing as “maybe”
ON or OFF
no such thing as a partial signal
ACTION POTENTIAL
• The neuron signal is called the “action
potential”
• When a neuron has “fired” a signal, it takes
time to reset and get ready to go again.
This is called
the refractory
period.
RESTING POTENTIAL
• When a neuron is not sending a signal, it is at
rest
• This is different than refractory period
because when a neuron is at resting potential
it is waiting to fire NOT unable to fire
Neuron Impulses are like…
Neurotransmitters
• Neurotransmitters are chemical molecules
which are found in the terminal buttons of
neurons.
• There are many different neurotransmitters.
– Examples:
• Acetylcholine – activates muscles
• Serotonin – involved in regulating moods
• Dopamine – related to schizophrenia and Parkinson’s
Terminal buttons release the
neurotransmitters into the synapse.
Neurotransmitters
Neurotransmitters float across
the space to the dendrites of
the next neuron in line.
Drugs work by imitating or blocking the
action of natural neurotransmitters
• ANTAGONIST = a drug that
blocks the effect of a
neurotransmitter
• AGONIST = a drug that boosts
the effect of a neurotransmitter
Computer Lab on Monday!
Mouse Party
• We will see how drugs and neurotransmitters
work to alter our behaviour