Biological Basis of
Behavior
So our brain chemistry and
make-up is responsible for
our behavior?
The Nervous System
I. The Neuron
- structural and
functional unit of the
nervous system
Three Parts of the
Neuron
Dendrite, Cell body, Axon
The Parts of the Neuron
1. Dendrites
- receive incoming messages
to the nerve cell
- resemble tree branches
2. Cell Body
- contains nucleus
Axon
conducts impulses away from
the nerve cell to other neurons
- Myelin sheath
- fatty material that covers the
axon and insulates it which
increases conduction speed
- Nodes of ranvier
-spaces between the
myelin sheath where
information can
become depolarized ( get
lost)
--
Terminal Buttons (end bulb)
- holds chemicals which
communicate with other
neurons by firing information
across the synapse to the next
cell body, organ or muscle
Synapse
-
a very small space in between
the end bulb and it’s adjacent
cell , organ or muscle
a. Transmitters - a chemical
messenger between
cells/neurons
Examples of
neurotransmitters- seratonin,
GABA, dopamine
- excitatory
- chemical locks open
and neurons are turned on
- inhibitory
- chemical locks are
closed and neurons turn off
• Seratonin is the brain chemical
that is associated with moods,
concentration and attention
Thinking about the information in
the last slides, explain what
happens in the brain with
people who are depressed
b. Receptors
- special areas on the dendrite
that function like a chemical
lock
Types of Neurons
a. Sensory or Afferent neurons
- transmit messages from
sensory receptors to the brain
and spine
a.Inter neurons
- located entirely
within the brain and
spinal cord, intervene
between sensory and
motor neurons
C. Motor or Efferent Neurons
- transmit impulses from sensory or
inter neurons to muscle cells that
contract or gland cells that secrete
(sends messages away from the
brain)
Examples- reflexes
• Babinski reflex
• Using information learned in
class, explain what happens
when you touch a hot stove
Somatic Nervous
system
• Controls voluntary activities
Such as…
Autonomic Nervous
system
• Controls involuntary responses
such as heart rate
Sympathetic Nervous
system
Sympathetic
- prepares the body for strenuous
activity
• - ex- speeds heart rate
Parasympathetic
- works to conserve energy in the
body and return it to its normal
state
Somatic Nervous
system
part of the nervous system that
activitiesPart of the Nervopus system that contr