Nervous System






  • Anatomy- This system includes brain, spinal cord and nerves (CNS and PNS).
  • Physiology- It is responsible for collecting, transferring and processing information with brain, spinal cord and peripheral nervous system.
  • The Nervous System is divided into the:
    1. Central Nervous System (CNS)
    2. Peripheral Nervous System (PNS)
Central Nervous System (CNS)
  • The CNS consists of the brain and spinal cord.
Brain
Portions of the Brain
  1. The cerebrum fills up most of the skull. It is involved in memory, problem solving, thinking and feeling. It also controls movement.
  2. The cerebellum sits at the back of the head, under the cerebrum. It controls coordination and balance.
  3. The diencephalon contains a few main structures; the main ones being the thalamus and hypothalamus.
  4. The brain stem, or “Vital Function Center,” sits beneath the cerebrum in front of your cerebellum. It connects the brain to the spinal cord and controls automatic functions such as breathing, digestion, heart rate and blood pressure.
Lobes of the Brain
  1. Frontal Lobe – Thought, Planning and Decision Making
  2. Parietal Lobe – Sensory Processing (Skin, Taste and Temperature) and Spacial Awareness/Recognition
  3. Occipital Lobe – Processing Visual Information
  4. Temporal Lobe – Processing Auditory Information, Emotions and Memory
Spinal Cord
  1. The spinal cord is an extension of the brain and is surrounded by the vertebral bodies that form the spinal column.
  2. The central structures of the spinal cord are made up of gray matter (nerve cell bodies), and the surrounding tissues are made up of white matter.
Meninges
  • The brain and spinal cord are protected by meninges.
  • There are three layers of meninges (superficial to deep).
    1. Dura Mater
    2. Arachnoid
    3. Pia Mater
Peripheral Nervous System (PNS)
  • The PNS is further divided into:
    1. Autonomic
    2. Somatic
Autonomic Nervous System
  • Includes spinal nerves that innervate smooth muscles (in organs), glands, and the heart muscle
  • Involuntary
  • The ANS is further divided:
    • Parasympathetic
      • “rest and digest” or “feed and breed”; housekeeping
    • Sympathetic
      • “fight or flight” functions
  • Massage is believed to stimulate the parasympathetic nervous system. This stimulates the vagus nerve and slows down the heart rate and breathing. This also increases peristalsis.
Somatic Nervous System
  • Sensory (Afferent) Nerves
    • Sensory neurons carry information from sense organs to the CNS.
  • Motor (Efferent) Nerves
    • Motor neurons carry information away from the CNS to the muscles.
Spinal Nerves
  1. 12 Pairs of Cranial Nerves
  2. 31 Pairs of Spinal Nerves
  3. 8 Cervical
  4. 12 Thoracic
  5. 5 Lumbar
  6. 5 Sacral
  7. 1 Coccygeal
  8. The longest nerve in the body is the sciatic nerve.
Cranial Nerves
  1. Olfactory – Sense of smell
  2. Optic – Vision
  3. Oculomotor – Eyelids, Pupil Size
  4. Trochlear – Eye Movement, Proprioception
  5. Trigeminal – Chewing, Face Sensation
  6. Abducens – Eye Movement
  7. Facial – Facial Expressions, Taste
  8. Vestibulocochlear – Balance, Hearing
  9. Glosso-Pharyngeal – Tasting, Swallowing, Blood Pressure and Respiration
  10. Vagus – Speech, Swallowing, The Heart, Some Visceral Organs
  11. Accessory – Head Movement, Voice Production
  12. Hypoglossal – Tongue Movement
Nervous System Terms
  • Dermatome– This is an area of skin that is mainly supplied by a single spinal nerve.
  • Synapse– A synapse is a structure that permits a neuron to pass an electrical or chemical signal to another cell.
  • Neuron or Nerve Cell – The neuron is the basic unit of the central nervous system.
  • Neuroglia– Neuroglia is the supportive tissue of the nervous system.
  • Myelin– Myelin is the electrical insulator in the neuroglia.
  • Cauda Equina– This is literally translated to “Horse’s Tail”. Some lumbar and all sacral nerve roots exit in a bundle that resembles a horse’s tail.
  • Endorphins– Endorphins are pain-killing substances produced in the human body.