JAMES VALLEY VOCATIONAL TECHNICAL CENTER

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Central Nervous System

• JAMES VALLEY VOCATIONAL TECHNICAL CENTER

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Neuron Nerve Cell

• Basic structural unit nervous system
• Consists of
• nucleus
• nerve fibers /dentrites
• axon

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Nerves

• Sensory Nerves
• carry messages to brain and spinal cord from body
• Motor Nerves
• carry messages from brain and spinal cord to body

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• Connecting or Mixed Nerves
• Carry both sensory and motor messages

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Divisions of CNS

• CNS - central nervous system
• consists of brain and spinal cord

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• Peripheral Nervous System
• a. any nerves outside the brain and spinal cord
• b. Autonomic nervous system controls involuntary
  body functions

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Central Nervous System

• 1. Brain
• a. Mass of nerve tissue
• b. Protected by membranes the cranium or skull

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C. Cerebrum

• Largest section of the brain
• Responsible for
• reasoning, thought, memory, speaking, sensstion,
  sight, hearing, voluntary body movement

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D. Cerebellum

• Responsible for
• coordination of muscles, balance, posture,
  muscle tone

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E. Midbrain

• Responsible for
• conducting impulses between brain parts
• certain eye reflexes

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Pons

• Responsible for
• conducting messages to other parts of the brain
• Reflex actions such as chewing, production of
  saliva

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G. Medulla Oblongata

• Lowest part of brain stem
• Connects to the spinal cord
• Responsible for
• regulating heart beat, respirations, swallowing,
  coughing, b/p

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2. Spinal Cord

• Goes down back of body from Medulla Oblongata
• Surrounded and protected by vertebrae
• Responsible for reflex actions
• Carries sensory and motor messages

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3. Meninges

• Consists of 3 membranes
• Covers and protects the brain and spinal cord

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Three Membranes

• C. Dura mater
• thick, tough outer layer
• D. Arachnoid membrane
• middle delicate weblike layer
• E. Pia mater
• inner most layer with blood vessels to nourish
  the nerves

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4. Ventricles

• Four hallow spaces located in the middle of the
  brain.
• Connected to each other
• Filled with fluid called cerebrospinal fluid

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Cerebrospinal Fluid

• Circulates continuously
• Serves as shock absorber to protect brain and
  spinal cord

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• Carries nurients to parts of brain and spinal
  cord
• helps remove metabolic products wastes
• after circulation, absorbed into the blood
  vessels of the dura mater.

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Peripheral Nervous System

• Made of all nerves outside the brain and spinal
  cord
• Consists of cranial and spinal nerves

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A. Cranial Nerves

• 12 pairs their branches
• Some responsible for special senses sight,
  hearing, taste, smell
• Others receive sensations touch, pressure, pain,
  temperature

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B. Spinal Nerves

• 31 pairs their branches
• carries messages to from the spinal cord
• Both sensory and motor nerves

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• 31 spinal nerves
• 8 cervical
• 12 thoracic
• 5 lumbar
• 5 sacral
• 1 coccygeal

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3. Autonomic Nervous System

• Helps maintain a balance in involuntary functions
  of the body. But allows the body to react in
  times of emergency.

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2 divisions of ANS

• Parasympathetic
• counter acts the sympathetic ns after the
  emergency

• Sympathetic nervous system
• acts in emergency

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• SNS
• increase heart rate
• increase resp. rate
• increase b/p
• decrease digestive system activity

• PNS
• decrease heart rate
• decrease resp. rate
• decrease b/p
• increase digestive system activity