Download Ch. 35.3

Ch. 35.3
 Neurons
join together to form a complex
network; NERVOUS SYSTEM
 2 major sections
• Central nervous system (CNS)
• Peripheral nervous system (PNS)
 CNS
is the CONTROL CENTER of the
body (think of a MOTHERBOARD of a
computer)
 CNS relays messages, processes
information, and analyzes information
 PNS relays information from environment
to the CNS
 Consists
of the brain and spinal cord
 Skull and vertebrae protect brain and
spinal cord
• Wrapped in MENINGES  connective tissue
• CEREBROSPINAL FLUID is in between the layers
 Acts as a shock absorber and protects the CNS
 Contains
~ 1 billion neurons
 Main ‘switch’ in the CNS
 CEREBRUM: largest part of the brain
• Controls voluntary activities of the body
• Intelligence, learning, and judgment
 Broken
into 2 hemispheres (connected
by the corpus callosum)
 Each
half of the brain controls the
opposite half
 Some studies state that the right side is
creativity, left side is more analytic
 Outer surface is cerebral cortex (gray
matter)
 White matter is the inner surface
 Located
in the back of the skull
 Coordinates and balances the actions of
the muscles
 Connects
the brain and the spinal cord
• Pons and medulla oblongata
 Acts
as a switchboard of information for
the brain and rest of the body
• Blood pressure
• Heart rate
• Breathing
• swallowing
 Found
between the brain stem and
cerebrum
 Thalamus receives messages from the
sense organs
 Hypothalamus controls recognition of
hunger, thirst, fatigue, anger, and body
temp
 Main
communications link between
brain and the body
 Reflexes
are processed by spinal cord
• Quick, automatic response to a stimulus
• Allows body to respond to danger immediately
 SOMATIC
NERVOUS SYSTEM: regulates
activities that are CONSCIOUS CONTROL
• MOVEMENT (motor neurons)
 Regulates
involuntary body functions
• Not under conscious control
 Heartbeat
 Contraction of smooth muscle
 Broken
into SYMPATHETIC and
PARASYMPATHIC nervous systems
• Work as opposites of each other (one makes
something ‘go,’ the other makes it ‘stop’)