Download Neurons and Neurotransmitters

History of Biological Psychology
• Plato was the first to suggest that
the mind was in the head.
• In the 1800’s, Franz Gall proposed
phrenology - studying bumps on the
head for character traits and
suggesting different parts of the
brain control different aspects of
behavior.
Biological Psychology
Biological Psychology
is the scientific study of
links between biological
and psychological
processes.
Biological Psychology
• Our study begins with bottom up
processing: processing that begins
with the nerve cells and goes up to
the brain.
• We will also look at top down
processing: how our thinking and
emotions affect our behavior.
Neurons
and
Neurotransmitters
Brain
(CNS)
Nervous System
An extensive network
of specialized cells
that carry information
to and from all parts
of the body.
Nerves
(PNS)
Spinal
Cord
(CNS)
The Neurons and the Neurotransmitters:
The Structure of the Neuron
• Neuron (NEW-ron)
– the basic cell that makes up the nervous
system and which receives and sends
messages within that system.
• Neurotransmitters
– Specialized chemicals that facilitate or
inhibit the transmission of impulses
from one neuron to the next
The Neurons and the Neurotransmitters:
The Structure of the Neuron
• Most neurons are made of three
parts:
– cell body (soma)
• contains the nucleus
• keeps the cell alive and functioning
– dendrites
• receives signals from other neurons
– axon
• slender, tail-like extension of the neuron
• sprouts into branches, each ending in a
bulbous axon terminal
The Neurons and the Neurotransmitters:
The Structure of the Neuron
• Other parts of the neuron
– axon terminal
• Bulbous end of the axon where signals move
from the axon of one neuron to the
dendrites or cell body of another
– myelin
• Fatty substances that coat the axons of
neurons to insulate, protect, and speed up
the neural impulse.
• Insulates the neuron.
• Bundles of myelin-coated axons travel
together in “cables” called nerves.
The Neurons and the Neurotransmitters:
Neural Communication
• Resting potential
• Action potential
− Neuron fires an impulse
• Neurons generate chemical electricity
− Positive & negative ions
The Neurons and the Neurotransmitters:
Neural Communication
The Neurons and the Neurotransmitters:
Neural Communication
The Neurons and the Neurotransmitters:
Neural Communication
The Neurons and the Neurotransmitters:
Neural Communication
The Neurons and the Neurotransmitters:
Neural Communication
The Neurons and the Neurotransmitters:
Neural Communication
LO 4.2
What are neurons, and how do they work?
• All-or-none - referring to the fact
that a neuron either fires completely
or does not fire at all.
• Return to resting potential.
The Neurons and the Neurotransmitters:
Neural Communication
• After a neuron fires there is a Refractory
Period – a period of inactivity after it has
fired.
The Neurons and the Neurotransmitters:
Communication between Neurons
• Axon terminals are separated from
the receiving neurons by fluid-filled
gaps: synaptic gap (or cleft).
• Synapse
– junction where axon terminal of sending
neuron communicates with receiving
neuron
The Synapse
The neuron's
electrical impulse
reaches the
synaptic knobs,
triggering the
release of the
neuron's chemical
messengers, called
neurotransmitters,
from the synaptic
vesicles and into
the cleft.
Neurotransmitters
• Chemical substances that transmit
messages between neurons
• Released into synapse by axon terminals
of sending neuron
• Bind to receptor sites on dendrites of
receiving neuron
• Taken back into axon terminal by the
process of reuptake
How Drugs and Other Chemicals Alter
Neurotransmission
• Agonist = a molecule that, by binding to a
receptor site, stimulates a response.
• Antagonists = a molecule that, by binding to
a receptor site, inhibits or blocks a response.