The Central Nervous System

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The Central Nervous System

• The central nervous system (CNS) consists of the
  spinal cord and brain.

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Organization of the Nervous System
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• Both are protected by bone, wrapped in protective
  membranes called meninges, and surrounded and
  cushioned with cerebrospinal fluid that is
  produced in the ventricles of the brain.

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• The ventricles are interconnecting cavities that
  produce and serve as a reservoir for
  cerebrospinal fluid.
• The CNS receives and integrates sensory input and
  formulates motor output.

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Gray matter contains cell bodies and short,
nonmyelinated fibers white matter contains
myelinated axons that run in tracts.
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The Spinal Cord

• The spinal cord extends from the base of the
  brain through the vertebral canal.

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• Structure of the Spinal Cord
• A central canal holds cerebrospinal fluid.
• Gray matter of the spinal cord forms an H and
  contains interneurons and portions of sensory and
  motor neurons.
• White matter consists of ascending tracts
  (dorsally) taking sensory information to the
  brain and descending tracts (ventrally) carrying
  motor information from the brain. Tracts cross
  just before entering the brain. So left ??right.

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YOU NEED TO KNOW THIS ANATOMY
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YES, EVEN IF IT IS SIDEWAYS OR UPSIDE DOWN !
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Functions of the Spinal Cord

• The spinal cord is the center for many reflex
  arcs.
• It also sends sensory information to the brain
  and receives motor output from the brain,
  extending communication from the brain to the
  peripheral nerves for both control of voluntary
  skeletal muscles and involuntary internal organs.
  
• Severing the spinal cord produces paralysis.

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The Brain

• The brain has four cavities called ventricles.
• The cerebrum has two lateral ventricles, the
  diencephalon has the third ventricle, and the
  brain stem and cerebellum have the fourth
  ventricle.

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The Cerebrum

• The cerebrum or telencephalon has two cerebral
  hemispheres connected by the corpus callosum.
• .

SEE THE C
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Cerebral Lobes
Learning, memory, language and speech take place
in the cerebrum. Sulci divide each hemisphere
into lobes including the frontal, parietal,
occipital, and temporal lobes
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I need some HELP here !
FAsT - FrontalPEOPLE - Parietal TAKE -
Temporal OUT - Occipital CHEESE -
Cerebellum BURGERS - Brain Stem
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The Cerebral Cortex

• The cerebral cortex is a thin, highly convoluted
  outer layer of gray matter covering both
  hemispheres.
• The primary motor area is in the frontal lobe
  this commands skeletal muscle.
• The primary somatosensory area is dorsal to the
  central sulcus or groove.
• The primary visual area is at the back occipital
  lobe.
• The temporal lobe has the primary auditory area.

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Language and Speech

• Language and speech are dependent upon Brocas
  area (a motor speech area) and Wernickes area (a
  sensory speech area) that are involved in
  communication.
• These two areas are located only in the left
  hemisphere the left hemisphere functions in
  language in general and not just in speech.

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The Diencephalon (Two in the Head)

• The hypothalamus and thalamus are in the
  diencephalon that encircles the third ventricle.
  
• The hypothalamus controls homeostasis and the
  pituitary gland, and the thalamus receives all
  sensory input except smell and integrates it and
  sends it to the cerebrum.

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The Cerebellum little brain

• The cerebellum receives sensory input from eyes,
  ears, joints and muscles and receives motor input
  from the cerebral cortex.
• It integrates this information to maintain
  posture, coordination and balance.
• The cerebellum is involved in learning of new
  motor skills, such as playing the piano or
  hitting a golf ball.

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The Brain Stem

• The brain stem contains the medulla oblongata,
  pons, and midbrain.
• The medulla oblongata and pons have centers for
  vital functions such as breathing, heartbeat, and
  vasoconstriction.
• The medulla also coordinates swallowing and some
  other automatic reactions (many reflex centers
  for heartbeat, breathing and BP)
• The midbrain acts as a relay station between the
  cerebrum and spinal cord or cerebellum.

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The Reticular Formation

• The reticular formation is a complex network of
  nuclei and fibers that extend the length of the
  brain stem.
• One portion of the reticular formation, called
  the reticular activating system, arouses the
  cerebrum via the thalamus causing alertness.
• It is believed to act as a filter for incoming
  sensory impulses.