1. The Nervous System
Chapter 4
Section 1

2. Two Systems in One Functions Central Nervous System (CNS)
Gather and interpret information
Respond to information as needed
Central Nervous System (CNS)
Brain
Spinal Cord
Peripheral Nervous System (PNS)
All other parts of the nervous system
Nerves connecting body to CNS

3. Structure Neuron: a nerve cell, specialized to transfer messages
Can be very short or quite long
Impulse: Message that travels along neurons in the form of electrical energy
Can be very slow or extremely fast

4. Neuron Dendrites: branches that receive information
Axon: carries the electrical impulse
Axon terminal: branches that pass information to other cells

5. Respond to Environment
Stimuli: anything that causes a change in an organism
Stimuli can be internal or external
Response: reaction to the stimuli
Reflex: an involuntary and almost immediate response to a stimuli
Sensory neurons: use receptors to gather information from in and around your body

6. Respond to Environment cont.
Messages are sent to the CNS from sensory neurons for processing
Involuntary- controlled automatically by the brain
Voluntary- intentional actions controlled by the brain
Motor neurons: neurons that send impulses from the CNS to other systems
Nerve: multiple axons bundled with blood vessels and connective tissue to transmit information

7. Organization Nervous System CNS PNS Sensory (receive) Motor (send)
Brain
Spinal Cord
Cerebrum
(thinking, senses, memories, voluntary)
Medulla (involuntary)
Somatic
(voluntary)
Autonomic
(involuntary)
Cerebellum (movement, balance, posture)
Sympathetic
(fight/flight)
Parasympathetic
(rest & digest)

8. Extension
Would you like to have a neurological condition where you were unable to feel pain?