AMA 175 - Anatomy

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AMA 175 - Anatomy Physiology/Medical
Terminology/Pathology 6 Nervous System
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Nervous System

• Function One of the most complex systems in the
  body. Contains more than 100 billion nerve cells.
  Coordinates all the activities of the human body
  both voluntarily or consciously and involuntarily
  or unconsciously. (Sight, taste, hearing, touch,
  speaking, moving muscles, thinking, breathing and
  the heart pumping blood and more).
• Nervous impulses (the release of electrical
  energy), travel all over the body from external
  receptors (sense organs) to the brain, where they
  are interpreted, and are then sent back to the
  appropriate parts of the body.

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Structure of the Nervous System

• 2 major divisions Central and Peripheral
• Central Nervous System
• Brain controls body activities cerebrum
  controls thought medulla oblongata in the brain
  stem controls involuntary such as respiratory,
  cardiac and vasomotor
• Spinal Cord column of nervous tissue extending
  from the medulla oblongata to the lumbar area of
  the spinal cord (nerves go from here to all parts
  of the body)

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Structure of the Nervous System continued

• 2 major divisions Central and Peripheral
• Peripheral Nervous System
• Cranial Nerves carry impulses between the brain
  and the head and neck (exception is the vagus
  nerve which carries messages to and from the
  neck, chest and abdomen) mainly voluntary
• Spinal Nerves carry messages between the spinal
  cord and the chest, abdomen and extremities
  mainly voluntary
• Plexus large networks of nerves in the
  peripheral nervous system

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Structure of the Nervous System continued

• Autonomous Nervous System included in the
  peripheral nervous system, function involuntarily
  to control breathing, cardiovascular, digestion
  etc
• Sensory (afferent) nerves carry messages toward
  the spinal cord and brain
• Motor (efferent) nerves carry messages from the
  spinal cord and brain to muscles telling them how
  to respond
• Sympathetic Nerves stimulate the body in times
  of stress and crisis by increasing heart rate,
  relax airways for more oxygen, stimulates adrenal
  gland to secrete adrenaline, inhibits digestion
• Parasympathetic Nerves act as a balance to
  sympathetic and restore homeostasis after crisis
  is over

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