Download Unit III: Biological Bases of Behavior

Unit III:
Biological Bases of
Behavior
Ms. Justice
AP Psychology
2014-2015
Unit III - Overview
9 – Biological Psychology & Neurotransmission
10 – The Nervous & Endocrine Systems
11 – Studying the Brain & Older Brain Structures
12 – The Cerebral Cortex
13 – Brain Hemisphere Organization & the
Biology of Consciousness
14 – Behavior Genetics: Predicting Individual
Differences
15 – Evolutionary Psychology
Unit III:
Biological Bases of
Behavior
Module 9
Biological Psychology &
Neurotransmission
Biology, Behavior, and Mind
9-1
Biology, Behavior, and Mind
9-1
• Phrenology - Franz Gall was correct in his
assumptions that different parts of the brain
do control different aspects of behavior…
but that’s about it
• Biological psychology - study the
links between biological activity
and psychological events
Neurons
9-2
Neurons
9-2
The body’s information system is built from billions
of interconnected cells called neurons.
Hi! I’m a
neuron… some
of my friends
call me “nerve
cell”
Neuron
A nerve cell, or a neuron, consists of many
different parts:
9-2
Parts of a Neuron
9-2
Cell Body: Life support center of the neuron.
Dendrites: Branching extensions at the cell body. Receive
messages from other neurons.
Axon: Long single extension of a neuron, covered with
myelin [MY-uh-lin] sheath to insulate and speed up
messages through neurons.
Terminal Branches of axon: Branched endings of an axon
that transmit messages to other neurons.
Action Potential
9-2
A neural impulse. A brief electrical charge that travels
down an axon and is generated by the movement of
positively charged atoms in and out of channels in the
axon’s membrane.
Action Potential
9-2
Threshold
9-2
threshold: the level of stimulation required to trigger
a neural impulse
Each neuron receives excitatory and
inhibitory signals from many neurons.
When the excitatory signals minus the
inhibitory signals exceed a
minimum intensity (threshold)
the neuron fires an action potential…
or if the excitatory party animals
outvote the inhibitory party poopers,
the party’s on.
How Neurons Communicate
9-3
Synapses
9-3
Synapse [SIN-aps] - a junction between the axon tip of the
sending neuron and the dendrite or cell body
of the receiving neuron.
This tiny gap is called the synaptic gap or cleft
(which is less than a millionth of an inch wide!)
Neurotransmitters
Neurotransmitters are
chemicals released
from the sending
neuron that travel
across the synapse and
bind to receptor sites on
the receiving neuron,
thereby influencing it to
generate an action
potential.
9-3
Reuptake
Excess neurotransmitters in
the synapse are reabsorbed
into the sending neurons
through the process of
reuptake.
9-3
How is a flushing toilet like a
neuron firing?
9-3
How is a flushing toilet like a
neuron firing?
9-3
•All-or-nothing principle – the toilet either flushes completely or not at all; it doesn’t
flush a little or a lot
•Direction of impulse – the toilet only flushes one way, the impulse can’t come the
other direction (you hope!)
•Refractory period – after you flush the toilet, it won’t flush again for a certain period
of time, even if you push the handle repeatedly
•Threshold – you can push the handle a little bit, but it won’t flush until you push the
handle past a certain point (this corresponds to the level of excitatory
neurotransmitters that a neuron must absorb before it will fire)
•Resting potential –the toilet is waiting to fire, and the water in the tank represents
the overall negative charge inside the neuron waiting for depolarization
•Action potential – opening the flap in the tank and the water rushing through the
pipes
How Neurotransmitters
Influence Us
9-4
Table 9.1, p. 82
9-4
Agonist versus Antagonists
9-4
Figure 9.6, p. 83