1. THE
NERVOUS
SYSTEM

2. • Your body performs many functions that maintain
life, such as heartbeat, temperature, digestion
and blood pressure.
• The regulation of conditions that maintain life is
called homeostasis.
• The nervous system is used by your body to
maintain homeostasis

3. • Neurons are nerve cells
• Neurons are made up of dendrites and axons
• Dendrites receive impulses from other neurons
• Axons carry impulses away from the neurons

6. • There are three types of neurons:
- sensory neurons receive information and send
impulses to the brain and spinal cord
- interneurons in the brain and spinal cord relay
impulses to the motor neurons
- motor neurons conduct impulses to muscles or
glands throughout the body

8. • To move from one neuron to another, an impulse
crosses a small space called a synapse

10. • The Central Nervous System (CNS) contains the
brain and the spinal cord

11. • The Peripheral Nervous System (PNS) is made up
of all the nerves outside the CNS, including:
- cranial nerves (in the head)
- spinal nerves
* The PNS connects the brain and spinal cord to
other body parts

12. The BRAIN
• The brain is an organ of soft nervous tissue
which functions as the center of sensation and
intellectual activity
- (that’s your senses and ability to think) 

14. • The brain coordinates all of your body’s activities
• The brain is protected by the skull, three
membranes, and a layer of cranial fluid
• The brain is divided into three major parts: the
cerebrum, the cerebellum, and the brain stem

15. BRAIN STEM

17. • The cerebrum is the largest part of the brain.
• It is where thinking takes place, the center of
intellectual activity

18. • Also in the cerebrum:
- impulses from the senses are interpreted
- memory is stored
- movements are controlled
• The bumpy outer layer
of the cerebrum is called
the cortex

19. • The cerebellum is the part of the brain that
controls voluntary muscle movements,
maintains muscle tone and helps maintain
balance

20. • The brain stem extends from the cerebrum and
connects the brain to the spinal cord
• The brain stem is made up of the midbrain, the
pons, and the medulla

22. • The spinal cord is
an extension of the
brain stem
• It is made up of bundles
of neurons that carry
impulses from body parts
to the brain, and from the
brain to the body parts

23. • The spinal cord is protected by bones called
vertebrae
• Injury to the spine can cause paralysis, the loss
of muscle movement.
• The higher up the spine the injury is, the more
of the body that is affected

25. • In the Peripheral Nervous System (PNS), there
are two divisions:
• The somatic system controls voluntary actions –
movements you choose
• The autonomic system controls involuntary
actions like heart rate and breathing

27. • A reflex is an involuntary response to a stimulus
• A reflex involves a simple nerve pathway called a
reflex arc
• A reflex allows the body to react to a potentially
dangerous stimulus quickly, without having to
think about it (such as heat)
• Reflexes are controlled in the spinal cord, not the
brain; the brain acts after a reflex (putting on
burn cream, for example)

28. • The sensory systems are parts of the nervous
system responsible for processing sensory
information
• Sense organs are specialized organs that
initiate the process of sensory perception
• The body’s main sense organs are the eyes,
ears, tongue, nose and skin

29. • A sensory system consists of sensory
receptors, neural pathways, and parts of
the brain involved in sensory perception