CENTRAL NERVOUS SYSTEM

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CENTRAL NERVOUS SYSTEM
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CNS

• Capable of evaluating incoming info and
  formulating responses to changes that threaten
  our homeostatic balance
• 2 protective coverings for the brain and spinal
  cord
• Outer covering bone
• Inner covering membrane called meninges

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• 3 layers that make up the meninges
• 1. Dura mater (outer) made of strong white
  fibrous tissue
• Forms the inner periosteum of the cranial bone
• 2. Arachnoid membrane delicate cobwebby
  middle layer
• 3. Pia mater transparent inner layer that
  connects to brain and spinal cord

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• 3 important inward extensions of dura mater
• 1. Falx cerebri longitudinal fissure that
  separates the cerebral hemisphere into two parts
• Superior sagittal sinus located above the falx
  cerebri fissure
• Stores blood from brain tissue for the return
  trip to the heart

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• 2. Falx cerebelli separates the cerebellum
  into two halves (right and left sides)
• 3. Tentorium cerebelli separates the
  cerebellum from the cerebrum
• Forms a tent-like covering over the cerebellum

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• 3 of several spaces found around the meninges
• 1. Epidural space immediately outside the dura
  mater, but inside the bony coverings of the brain
  and spinal cord
• Contains supporting fat and connective tissue

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• 2. Subdural space is between the dura mater
  and arachnoid
• Contains a small amount of lubricating serous
  fluid
• 3. Subarachnoid space is under the arachnoid
  and outside the pia mater
• Contains a lot of cerebrospinal fluid

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• The meninges of the cord continue down some
  distance after the end of the spinal cord
• Filum terminale slender filament of the pia
  mater that blends with the dura mater to form a
  cord that disappears into the periosteum of the
  coccyx