The Spinal Cord Notes

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The Spinal Cord Notes

• acts as a communication link between the Brain
  and the Peripheral Nervous System

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Kevin Everett Good Morning America Interview

• http//www.youtube.com/watch?veFkkIvKDiZY

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The Spinal Cord

• is continuous with the brain and emerges from the
  foramen magnum at the base of the skull
• stretches downward for approx.  42 - 45 cm
  through the vertebral foramen
• there are 31 pairs of spinal nerves that emerge
  from the spinal cord through the intervertebral
  foramen 

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2 Types of Nerves Radiating from Spinal Cord

• the dorsal roots contain Neurons that carry
  signals to the CNS from various kinds of Sensory
  Neurons (Affectors).
• the ventral roots contain the Axons of Motor
  Neurons, which are neurons that contact and carry
  information to the Muscles and Glands
  (Effectors).

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2 Types of Matter within Spinal Cord

• gray matter - an area of unmyelinated neurons
  where cell bodies and synapses occur
• synapses between sensory and motor and
  interneurons
• cell bodies of the interneurons and motor neurons
  
• white matter - an area of myelinated fiber tracts

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Reflexes the simplest responses to a stimulus

• Ex. Sneezing and Blinking
• produces a rapid motor response to a stimulus
  because the Sensory Neuron synapses directly with
  a motor neuron in the Spinal Cord.
• are very fast and most never reach the brain

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The Reflex Arch

• Knee is struck
• Receptors in the skin stimulated
• Sensory Neurons carry the impulse to Spinal Cord
• A group of Neurons in the Spinal Cord
  AUTOMATICALLY ACTIVATES Motor Neuron
• These Motor Neurons cause the Muscles (effectors)
  in your leg to contract, pulling you foot away.