The central nervous system (CNS) consists of the brain and spinal cord. It controls most functions of the body and processes information from the peripheral nervous system (PNS), which includes all nerves outside the CNS. The brain directs responses and communicates with the body via the spinal cord. The three main regions of the brain that receive and process information are the cerebrum, cerebellum, and brain stem. The brain stem controls involuntary actions, while the cerebellum coordinates muscle actions and balance.

1. Central Nervous System
• The CNS is the control center
• Central Nervous System (CNS) = the
division of the nervous system
consisting of the brain and spinal
cord.
• Peripheral Nervous System (PNS) =
the division of the nervous system
consisting of all of the nerves
located outside the CNS.
• It includes the brain and spinal
chord.

2. Central Nervous System
• Brain = the part of the nervous system
that controls most functions of the
body.
• Spinal Cord = the thick column of nerve
tissues that links the brain to most of
the nerves in the PNS.
• Most impulses from the PNS travel
through the spinal chord to get to the
brain.
• Your brain directs the response.
• The impulse usually travels from the
brain through the spinal column to the
PNS.

3. The Brain and Spinal Cord
• Brain contains 100
billion neurons.
• All interneurons in the
brain.
• There are three main
regions of the brain
that receive and
process information.
• The are the cerebrum,
the cerebellum, and
the brain stem.

4. What are three main
regions of the brain
that receive and
process information?

5. Cerebrum
• Cerebrum = the part of the brain that interprets
input from the senses, controls movement, and
carries out complex mental processes.
– learning and remembering
• Right hemisphere
– Controls skeletal muscles on the left side of the body
– Associated with creativity and artistic ability
• Left Hemisphere
– Controls skeletal muscles on the right side of the body
– Mathematical skills, language and logical thinking

7. Cerebellum and Brain Stem
• Cerebellum = the part of the brain that
coordinates muscle action and helps maintain
balance.
• Brain Stem = the part of the brain that lies
between the cerebellum and the spinal cord,
and controls the body’s involuntary actions.

8. WHAT ACTIONS DOES THE BRAIN
STEM CONTROL?

9. The Spinal Cord
• The spinal cord is
the link between
your brain and
the peripheral
nervous systems

10. Peripheral Nervous System
• The peripheral nervous
system consists of a network
of nerves that branch out
from the central nervous
system and connect to the
rest of the body.
• The peripheral nervous
system is involved in both
involuntary and voluntary
actions.

11. How Spinal Nerves Function
• Signals travel in both directions.
• Both sensory and motor neurons.
• Sensory – PNS to CNS
• Motor – CNS to PNS

12. Somatic and Autonomic Systems
• Somatic Nervous System = the groups of
nerves in the PNS that controls voluntary
actions.
• Autonomic Nervous System = the group of
nerves in the PNS that controls involuntary
actions.

13. WHAT KINDS OF ACTIONS ARE
CONTROLLED BY THE AUTONOMIC
NERVOUS SYSTEM?

14. Reflexes
• Reflex = an automatic
response that occurs
rapidly and without
conscious control.
• Reflexes help to protect
the body.

15. Signaling the Brain
• It takes longer for the pain impulse to get to
the brain than it does for the reflexes to occur.
• Why is it important for the brain to be notified
of events requiring a reflex action?
• It helps a person:
– recognize possible dangers
– learn to avoid certain circumstances
– understand why an injury occurred

16. Nervous System Injuries
• Concussions and spinal cord injuries are two
ways in which the central nervous system can
be damaged.

17. Concussions
• Concussion = a bruiselike injury of the brain
that occurs when the soft tissue of the brain
collides against the skull.
• Tissue will heal itself.
• Symptoms
– headache
– lose consciousness
– confusion
– drowsy

18. Spinal Cord Injuries
• When the spinal cord is
cut or crushed.
• Damaged axons fail to
carry impulses.
• Paralysis – loss of
movement in some part
of the body.