Download The Nervous System

The Nervous System
• The nervous system
is made of 2 parts:
• The CNS (central
nervous system)
– Consists of the brain
and spinal cord
The PNS (peripheral
nervous system)
consists of nerves
outside the brain and
spinal cord
The Central Nervous System
Brain
• The brain is a large
mass of neurons
located in the cranial
cavity and is
protected by the skull
and 3 tough layers
called the meninges
• Fluid called
cerebrospinal fluid is
found between the
layers to further
protect the brain
Parts of the Brain
• Cerebrum- large
folded part of the
brain
• It is the center for
voluntary action
• Where sensory
impulses are
interpreted
• Where motor
activities are initiated
• Where thinking,
memory and
reasoning occur
Cerebellum
• Lower back part of
the brain
• Coordinates motor
activities and helps to
maintain balance
Medulla Oblongata
• Located below the
cerebellum
• Controls involuntary
activity like:
– Breathing, sneezing,
heartbeat, blood
pressure, coughing,
peristalsis
Spinal Cord
• Carries impulses
between the brain
and the body
• It is protected by the
vertebrae
It is the center for reflex
action
The Peripheral Nervous System
• Has 2 parts:
• The somatic:
– Controls voluntary muscles
• The autonomic
controls involuntary
muscles of the heart,
digestive tract ,
diaphragm etc.
• The autonomic
nervous system has 2
parts:
– Sympathetic :
accelerates body
activities
– Parasympathetic :
slows down body
activities
Malfunctions of the Nervous
System
• Cerebral palsy
– Damage to motor
centers of the brain
before or during birth ;
causes poor muscle
coordination and
speech difficulties
• Meningitis
– Inflammation of the
membranes
surrounding the brain
and spinal cord
– Can be viral or
bacterial
• Stroke
• Damage to the nerves
in a particular part of
the brain due to
blockage or rupture of
blood vessels, which
prevents oxygen from
reaching the brain
cells
• May result in
paralysis, memory or
speech loss or
blindness
• Polio
– Viral disease of the
nervous system
– May cause paralysis
– Prevented by
immunization
Type:
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