Download Class 3 - Neurons - Napa Valley College

Psychology 001
Introduction to
Psychology
Christopher Gade, PhD
Office: 621 Heafey
Office hours: F 3-6 and by apt.
Email: [email protected]
Class WF 7:00-8:30
Neurons and Neurotransmitters
Why do we need to know
about this stuff?

In order to understand human behavior, psychologists
often look to the brain. In order to understand the brain,
you need to understand the parts that it’s made up of, and
how those parts work.


Car Example
Knowing this will help us understand what’s going on
(on the cellular level) when something wrong happens to
an individual (e.g. depression, schizophrenia, etc).

Car Example Continued
The Neuron

Neurons are nerve cells that
receive and transmit
information throughout the
body and brain.

The human body has roughly
80-100 billion neurons in it
by adulthood.

Located throughout our body
with the majority of them
being located in the brain.

Come in a number of
different sizes and are
utilized in a number of
different ways.
How Do We
Know About
this?
Answer: Staining
What a Neuron Looks Like

Cell body: contains the nucleus of the cell. Consider
this as the brain of the neuron.

Dendrites: widely branching structures that receive
transmissions (via neurotransmitters) from other
neurons.

Axon: a single, long, thin, straight fiber which
branches near its tip. Once a neuron is activated, a
neural impulse is sent down this part of the neuron into
the terminal branches.

Terminal Branches (AKA terminal buttons): the ends
of the axon that branch out and are responsible for the
release of the neurotransmitter that is needed for the
communication with other neurons.
The Supporting Staff

Glia Cells –
cells that
support neurons
by



Removing
waste
Insulating
neurons
(protection and
mylenation)
Synchronizing
activity
Neural Communication
The action potential is an
all-or-none signal that is
sent along the neuron. It
does not fade over time or
distance.
When an action potential
reaches the axon endings
it initiates the release of
neurotransmitters into the
synapse.
n
Synapse: the space
between the axon’s
terminal button and the
dendrite of the
subsequent neuron.
How Does the Action Potential
Occur?... Most of the time.

Once enough of the dendrites of a neuron have been
“activated” by neurotransmitters, a change in the
electrical charge of the neuron begins in the axon
hillock.

This charge is then sent down the axon of the cell in
order to tell the terminal branches of that cell to
release a neurotransmitter.

In other words, neurotransmitters are needed for a
cell to fire, so the more synapses in a neuron, the
more likely it will fire.

Once a neurotransmitter has been released into
the synapse, three things can occur to them.



Activation: the neurotransmitters can temporarily
cling to the dendrites of another neuron, and
influence this neuron based on the type of
neurotransmitter that was released.
Reuptake: the axon terminal can eventually “suck
back” the neurotransmitter that it released (recycling
at its best)
Diffusion/Metabolized: the neurotransmitter can be
broken down, washed away, or used up by other
cells and enzymes that are located in the synapse.
Neurotransmitter Examples
Dopamine (DA)
•
•
•
Important for motor functioning – Parkinson’s disease
involves selective deterioration of the region in the brain
that produces DA
Implicated in ‘reward’/positive emotional sensation,
motivation
High levels of DA are associated with schizophrenia
Serotonin (5-HT)
•
Implicated in psychological wellness/mood, SSRIs are
effective treatment for depression
•
Affects hunger, sleep cycles, and arousal