I. peripheral nervous system (PNS): nerves not in the brain or spinal cord
   1.somatic nervous system:
      A. this carries sensory information from skin, muscles, joints (afferents)
      B. connects voluntary muscles to the CNS (efferents)
   2. autonomic nervous system: nerves of the heart, blood vessels, glands, etc.
      A. sympathetic nervous system: mobilizes bodies resources for emergencies
      B. parasympathetic nervous system: allows the body to conserve its resources

II. central nervous system (i.e., the brain & spinal cord)
   1. covered by a membrane called the meninges
      A.dura matter, arachnoid layer, pia matter
 

   1. neuroaxis: an imaginary line through the spinal cord to the front of the brain
   2. anterior or rostral: toward the head or front of the brain
   3. posterior or caudal: toward the tail or back of the brain
   4. dorsal: is the back & top of the head
   5. ventral: faces the ground in 4 legged animals
   6. ipsilateral: refers to structures on the same side
   7. contralateral: refers to structures on the opposite side
   8. lateral: toward the outside
   9. medial: toward the middle

 10. to study the brain, we must slice it
     A. transversely, giving us coronal sections
     B. parallel to the ground, giving us horizontal sections
     C. perpendicular to the ground (parallel with neuroaxis), giving us sagital sections
 

I. Ventricular system: chambers in the brain
   1. four hollow interconnected chambers which CSF circulates through
     A. lateral ventricles:
     B. third ventricle:
     C. fourth ventricle:

   2. hydrocephalus: an excess of CSF (circulation becomes blocked)

   3. ventricles can enlarge with dementia & brain disease
 

II. hindbrain: lower brainstem
  1. medulla oblongata (oblong narrow)
     A. connected to the spinal cord (i.e., anterior to cord)
     B. neurons for life sustaining activities
     C. several nuclei for cranial nerves are here
     D. reticular formation (RF): occupies the central core of the brainstem

  2. pons: a bulge in the brainstem
     A. anterior to the medulla
     B. several nuclei for cranial nerves are here
     C. cerebellum strapped on the dorsal side
 

III. midbrain: upper brainstem
  1. anterior to the pons
  2. tectum (little hills): the dorsal part of the midbrain
     A. superior colliculi:
     B. inferior colliculi:
  3. tegmentum: lies beneath the tectum inside the brainstem
     A. rostral end of the RF
     B. substantia nigra:
 

IV. forebrain: the largest & most complex area of the brain

  1. thalamus: integrates information from the senses
    A. anterior to the midbrain
    B. several groups of nuclei are here
       a. e.g., lateral geniculate nucleus (LGN):
       b. e.g., medial geniculate nucleus (MGN):

  2. hypothalamus: on ventral surface of the brain
    A. below (i.e., ventral to) the thalamus
    B. regulates biological needs.
    C. pituitary hangs beneath

  3. limbic system:
    A. hippocampus: memory formation
      a. located beneath temporal lobe cortex

    B. amygdala: perception & storage of emotional events
      a. located beneath temporal lobe cortex
      b. Kluver-Bucy syndrome

    C. other limbic structures allow us to experience reward

  4. basal ganglia: caudate nucleus, putamen, globus pallidus
    A. Parkinson’s disease & Huntington's disease

  5. cerebral cortex: the outer most layer of the brain
    A. most of it contains 6 layers (laminae)

    B. cortical cells are also arranged into colomns

    C. consists of sulci (small grooves), fissures (large grooves), & gyri (bulges)
       a. central sulcus:
       b. lateral fissure:
       c. longitudinal fissure:

    D. is divided into four basic lobes
       a. occipital lobe: the most posterior cortex

       b. parietal lobe: dorsal to the lateral fissure & posterior to the central sulcus

       c. temporal lobe: ventral to the lateral fissure

       d. frontal lobe: dorsal to the lateral fissure & anterior to the central sulcus

    E. association cortex: for elaborate sensory processing

  6. corpus collosum: axons that connect the left & right hemispheres
 

II. The cord extends only about 2/3s of the column
  1. cauda equina:
 

III. There are 31 pairs of spinal nerves, each pair has a dorsal & ventral root.
  1. dorsal roots: afferent axons from unipolar neurons (cell bodies in the dorsal
           root ganglia). Many synapse in the dorsal horn.

  2. ventral roots: efferent axons from multipolar neurons (cell bodies in the ventral
           horn).

I. most serve both motor & sensory functions of the head & neck
  1. there are 12 pairs of cranial nerves
 

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