PSYCHOLOGY 260 1: BEHAVIORAL NEUROSCIENCE Jane Adams, Ph.D.

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Monday, Feb 13
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• Central Nervous System
• Protections for the Brain and Spinal Cord
• Meninges - the coverings around the brain and
  Spinal Cord
• Ventricles containing Cerebrospinal fluid
• The Blood-Brain Barrier

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• Central Nervous System
• Protections for the Brain and Spinal Cord
• Meninges - the coverings around the brain and
  Spinal Cord
• Ventricles containing Cerebrospinal fluid
• The Blood-Brain Barrier

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• The Ventricles
• hollow spaces within the brain that are filled
  with cerebrospinal fluid
• Lateral ventricles
• Third ventricle
• Cerebral aqueduct
• Fourth ventricle

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• The Ventricles
• hollow spaces within the brain that are filled
  with cerebrospinal fluid
• Lateral ventricles - in center of hemispheres on
  each side of brain
• Third ventricle - at midline of forebrain
  connects to lateral v. and 4th ventricle
• Cerebral aqueduct - center of midbrain connects
  3rd and 4th ventricles
• Fourth ventricle - center of hindbrain between
  the cerebellum and pons

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Cerebrospinal Fluid CSF secreted by the lining
of the lateral ventricles the choroid plexus, a
tissue filled with blood vessels. It pulls blood
cells out of plasma and sends the remaining fluid
into the ventricular space.
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• Cerebrospinal Fluid
• acts mechanically as a shock absorber for the
  brain
• mediates between blood vessels and brain tissue
  to assist in exchange of materials things the
  brain tissue needs or needs to get rid of
• forms in lateral ventricles, goes to 3rd then
  4th ventricle, then leaves and is circulated over
  the surface of the brain and spinal cord
• then absorbed back into the vascular system
  through veins that line the skull

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• Central Nervous System
• Protections for the Brain and Spinal Cord
• Meninges - the coverings around the brain and
  Spinal Cord
• Cerebrospinal fluid in the ventricles
• The Blood-Brain Barrier

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• The Vascular System of the Brain
• all the blood vessels in the brain
• brain needs glucose, oxygen, nutrients,
  precursor molecules for building proteins,
  hormones, neurotransmitters, etc.
• Brain uses 15 of resources but accounts for
  only 2 of body weight

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Active transport of nutrients, etc that brain
needs. Active transport - important molecules are
carried from blood into brain by carrier proteins.
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• The Blood-Brain Barrier
• protects brain from foreign substances in blood
• allows brain to get what it has evolved to need

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• The Blood-Brain Barrier
• the smallest and final branches of arteries
  (capillaries) are structurally different in brain
  
• in brain, capillaries are closed in a way that
  makes them selectively permeable to things in the
  blood
• blood contents that cross capillary wall must
  still cross a layer of astrocyte cells before
  available to enter neurons

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The Blood-Brain Barrier Important membranes that
must be crossed Capillary wall Astrocyte
cells Neuronal membrane - the cell wall around
neurons
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Active transport across capillary wall, astrocyte
layer, and neuronal membrane - carries nutrients
to neuronal membrane where also carried into
neuron by active transport across
membrane Passive transport also occurs - some
molecules dissolve in fatty tissues of the
membranes and sneak into neurons of brain.
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BBB is present in 85 of brain capillaries. BBB
does not exist around hypothalamus or pituitary
gland - need complete access to blood to monitor
and control hormone levels. BBB does not exist in
brainstem area known as the Area Postrema -
monitors blood for toxic agents presence causes
vomiting
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• Protections for the Brain
• Meninges - the coverings around the brain and
  Spinal Cord
• Cerebrospinal fluid in the ventricles
• The Blood-Brain Barrier