Download The Nervous System

Biology and Behavior
The Nervous System is our bodies “Blueprint”:
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It gathers & processes information
Responds to stimuli
Coordinates the workings of different cells
Regulates our internal functions
Nervous System is involved in
psychological processes such as:
- thought
- movement
- emotion - sensation
Nervous System: The Building Blocks
• Neurons (nerve cells) are the
basic units of the nervous system
• Location They run throughout
our whole body!
• Purpose communicate with one
another by sending & receiving
messages from the structures of
our body
Held in place & fed by Glial Cells:
- provide nutrition, support, &
insulation to neurons
Nervous System: The Building Blocks
• Types of Neurons:
– Motor send information
onward to control muscles
– Sensory bring senses in
from other senses
– Associative provide links
between neurons
Structure of a Neuron
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Cell Body (Soma): directs actions of the cell
Nucleus: contains genetic material for the cell
Dendrites: enables neuron to receive information
Axon: carry electrical signals (messages) out of the cells, sends a
chemical message to adjacent neurons via Axon/Terminals
• Myelin: insulates & protects Axons w/a fatty substance
Nervous System: Communication
• The Process of Communication:
– In order for message to be sent from
one neuron to another… must cross
a Synapse
junction between dendrites
via Axon Terminals (where
communication takes place)
Nervous System: Communication
• Neurons send messages across synapses (junctions)
by releasing…
Neurotransmitters chemicals
stored in sacs in the axon
terminals (look like “buttons”)
Nervous System: Communication
Fives Main Types of Neurotransmitters:
 Serotonin – affects mood, sleep, sensory perception, and
other functions, may play a role in psychological disorders
like depression
 Acetylcholine – involved in memory, muscle action, sleep,
emotions, those w/ Alzheimer’s have lower levels
 Dopamine – affects movement, attention, memory,
learning, plays role in addiction
 Norepinephrine – affects learning, memory, emotions,
eating, alertness, etc.
 Epinephrine – emotions, memory storage
Neurons are Communicating
Nervous System: Two Main Parts
Nervous System: Two Main Parts
Part 1: Central Nervous System
– Consist of brain & spinal cord
– Function receives, processes,
interprets, and stores sensory
information
Responsible for Spinal Reflexes:
- automatic & require no
conscious effort
- Ex: touch something hot and
immediately remove hand
Nervous System: Two Main Parts
Part II: Peripheral Nervous System
– Consist of all parts of the nervous system
outside the brain and spinal cord
– Function handles the central nervous system’s
input & output
Sensory Nerves:
- carry messages from
receptors to brain
Motor Nerves:
- carry messages from
CNS to muscles, glands,
and internal organs
Somatic Nervous System
– Controls skeletal muscles
– Permits voluntary actions
Autonomic Nervous System
– Regulates body’s vital
functions (blood vessels,
internal organs)
– Permits self-regulating actions
– Has two divisions:
Parasympathetic System:
- calms & relaxes the body
- Ex: Feel sick to your stomach
Sympathetic System:
- mobilizes body for action
- increases energy output
- Ex: Fight or Flight