Cerebrum:

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Cerebrum

• The major parts of the voluntary
• Brain..

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Frontal Lobe

• The frontal lobe begins at the central sulcus and
  extends down to the top of the lateral sulcus.
• It is the largest lobe of the brain and is
  protected by the frontal bone.

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Frontal Lobe contd

• The frontal lobe is the part of the brain that
  contains our
• Personality
• Morals and ethics
• Ability to form words for speaking
• Skeletal muscle movement (voluntary)
• The frontal lobe is the OUPUT center of the brain.

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Pre-Central Gyrus

• The gyrus located just in front of the central
  sulcus and has been mapped so that we know what
  part of the brain instructs that particular part
  of the bodys voluntary muscles.

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Parietal Lobe

• The parietal lobe is the major INPUT lobe.
• It is the files of our hardrive or memory. The
  more often the memory is enforced through
  repetition the linked up the memory becomes.
  Short-term memory hasnt had enough repetition to
  stay filed and can be lost quickly.

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Parietal Lobe contd

• Many memory problems can be seen in the elderly
  or people with Alzheimers. One common problem
  occurs when a patient can remember what happened
  when they were five, but cant seem to remember
  what they had for lunch. As the brain
  deteriorates, more long-term memory files are
  broken down.

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Parietal Lobe Contd

• Short-term memory problems can also be seen in
  head injury patients. They may recover reading,
  writing, speech, and motor skills, but they
  struggle in school because the brain can not seem
  to hold the short term lesson of the class long
  enough to be able to reinforce it.

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Parietal Lobe contd

• Other major functions of the parietal lobe
• Understanding speech (Brocas area)
• Recognition of objects, people, places, and
  events
• Memory of events and outcome of choices (files
  for the hard drive)

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Post-Central Gyrus

• The gyrus located just posterior to the central
  sulcus has been mapped so that we know what
  part of the brain receives input from what
  particular part of the body.

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Post-Central Gyrus Contd

• Sensory Homunculus
• Notice how some of the body part are larger than
  others. The larger the body part drewn on that
  part of the brain, the MORE brain area used for
  that part!
• This is why some areas of the body are more
  sensitive than others.
• Ex. Allergy testing The back is not one of the
  most sensitive areas, so testing here is less
  annoying to the pt.

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Occipital Lobe

• The occipital lobe is located in the back of the
  brain.
• Do you see with your eyes OR do you see with your
  brain?

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Occipital Lobe Contd

• The brain is easily fooled.
• Especially the occipital lobe!
• The cameras or the eyes are located at the
  front of the head (which helps in survival) and
  the image is wired under the brain, back to the
  occipital lobe.
• The occipital lobe receives images upside down
  and then breaks patterns down into familiar
  items.
• The parietal lobe helps identify these items with
  the use of language.

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Temporal Lobe

• The temporal lobe is located under the parietal
  and frontal lobes on the side of the brain.
• The temporal lobe is responsible for hearing and
  balance, it also helps place an identification
  with the sounds that the temporal lobe hears

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RECAP

• Frontal, Parietal, Occipital, and Temporal lobes
  of the brain make up the Somatic or Volumtary
  Brain.
• The frontal lobe is the only OUTPUT lobe or motor
  lobe of the voluntary brain.
• The parietal, occipital, and temporal lobes are
  all INPUT lobes.

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The Brain

• The Major Parts of the Involuntary Brain

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Cerebellum

• The cerebellum is located in the back of the
  brain under the occipital and temporal lobes.
• It has very fine and horizontal gyrus.
• The white matter forms a tree known as the tree
  of life or Arbor Vitae
• Controls coordinationIt is much like a traffic
  controller at an airport.
• It is quite developed (compared to the cerebrum)
  at birth and develops as the infant uses
  repetitive movements.

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Brain Stem Pons and Medulla Oblongata

• The Pons remember the poochy pons, since it
  pooches out from the brain stem
• The M.O. is found under the pons and exits the
  skull through the magnum foramen. It ends at C2.
• Controls breathing and connects the brain to the
  spinal cord.
• An injury here can cause quadriplegia and a quick
  death if breathing is not aided.

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Topics of Discussion

• Effects of Alcohol
• The real meaning of brain dead

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Use Your Grey Matter

• Grey Matter
• vs.
• White Matter

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White Matter.What we need to know first.

• Nerve cells (Neurons) carry messages in one
  direction.
• Most nerve cells have a oligodendrocyte
  (Responsible for insulating the CNS neurons)
  wrapped around them. - White Neurons
• Responsible for carrying messages to and form
  specific areas of the CNS, especially to the
  cortex of the brain.

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White Matter contd

• Think of white matter much like telephone lines
  going to and from a house.
• Think of the house as the decision maker of the
  brain (cortex)

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Cerebral Cortex

• Outer layer of the brain
• Composed of gray neurons
• Unmyelinated
• Carry messages slower
• 1-4 mph..much slower than white neurons (250
  mph!!!!)
• Choice making occurs here.
• Like voting
• Neurons vote and from the voting a choice is
  made.

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Cerebral Spinal Fluid. (CSF)

• Functions
• Supportive, protective cushion
• Reservoir of circulating fluid that, along w/
  blood, the brain monitors for changes in the
  internal environment
• Changes in CO2 content of CSF trigger homeostatic
  responses in the resp. control centers of the
  brainstem that help regulate the overall CO2
  content and pH of the body

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Fluid spaces

• CSF is found in the
• Subarachnoid space
• Around the brain and spinal cord
• Ventricles
• Large, fluid filled spaces w/in the brain
• There are 4
• Lateral (2) ..meet on the midline
• Third . thin vertical pocket of fluid below and
  medial to the lateral ventricle
• Fourth.tiny, diamond-shaped space where the
  cerebellum attaches to the back of the brainstem
• p.231

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Formation of CSF

• Formation
• Occurs mainly by separation of fluid from blood
  in the choroid plexuses
• Network of capillaries that project from the pia
  mater into the lateral ventricle and into the
  roofs of the 3rd and 4th ventricles
• Ependymal Cells
• Sheet of cells that cover the CP, and release CSF
  into the ventricles

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Circulation of CSF

• Formed by separation of fluid from bl.in the CP
  into the ventricles
• Circulates through the ventricles and into the
  central canal and subarachnoid spaces
• Absorbed back into the blood

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Statistics CSF

• In the average adult there is about 140mL
• 23mL in the ventricles
• 117mL in the subarachnoid space of brain and
  spinal cord
• Hydrocephalus
• When CSF is blocked
• Internal CSF builds up in the ventricles
• External CSF builds up in the sub.A space

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Spinal CordThe interstate that connects the
brain to the body!

• Structure
• Lies w/in the spinal cavity
• Extends from the foramen magnum to the lower
  border of the L1 (L3 for infants and young
  children)
• 45cm (18inches) in the ave. adult body
• Does NOT completely fill the spinal cavity
• Oval shaped cylinder that taper slightly as it
  descends and has 2 bulges
• Cervical region
• Lumbar region

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Spinal Cord contd

• 2 deep grooves just miss dividing the cord into
  symmetrical halves.
• Anterior median fissure (deeper/wider)
• Posterior median sulcus
• 2 bundles of nerve fibers project from each side
  of the Spinal cord
• Nerve Roots
• Dorsal nerve root sensory info. into SC
• Dorsal root ganglion cell bodies of these
  unicellular, sensory neurons make up a small
  region of gray matter

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Spinal Cord contd

• Ventral Nerve Root motor info. out of SC
• Cell bodies of these multipolar neurons are in
  the gray matter that composes the inner core of
  the SC
• Spinal nerves
• The dorsal and ventral nerve roots join together
• Component of the Peripheral NS

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Spinal Cord contd

• Cross Section view
• Gray matter looks like a flattened H
• Extends the length of the SC
• Limbs of the H are called
• Anterior horn or column
• Posterior horn or column
• Lateral horn or column
• Consist redominantly of cell bodues of
  interneurons and motor neurons

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Spinal Cord contd

• Cross Section view
• White matter
• Surrounding the gray matter, is subdivided in
  each half of the SC into 3 columns (or funiculi)
• Anterior
• Posterior
• Lateral
• Each column/funiculus consists of a lg. bundle of
  neree fibers (axons) divided into smaller bundles
• Tracts

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Spinal Cord contd

• Tracts contd
• The names of most SC tracts indicate
• 1. the white column in which the tract is
  located
• 2. the structure in which the axons that
  make up the tract originates
• 3. The structure in which they terminate
• Example the anterior spinothalmic tract

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Peripheral Nervous System
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The relationship of communication between the
spinal cord and nerves.

• Nerves are always found in the PNS (tracts are
  always pathways on the CNS)
• Sensory nerves ALWAYS go to the CNS
• Sensory nerves ALWAYS have a ganglion to house
  their nuclei
• Sensory nerves ALWAYS enter the dorsal horn to
  pass their messages along.

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The relationship of communication between the
spinal cord and nerves.

• Once the message has arrived at the spinal cord,
  it will then travel along sensory pathways or
  tracts up to the brains cortex for
  interpretation

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A choice has been made!!!

• The output or motor message once again travels
  along motor pathways or tracts down the spinal
  cord.
• Once arriving at the area that has the muscles to
  carry out the movements, the message exits the

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Motor nerves

• When a motor nerve hooks up with a muscle it
  can now tell it when to move, it is known as
  innervation.
• The combination of the sensory and motor nerve
  wrapped together produces a structure known as a
  spinal nerve.
• Because this nerve has both sensory and motor, it
  is known as a mixed nerve.

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PNS nerves

• 31 pairs of spinal nerves
• They enter and leave the spinal cord
• Not all nerves enter and leave the spinal cord,
  there are 12 pairs of nerves that enter and leave
  the brain only.
• Crainal nerves

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PNS nerves

• Cranial and spinal nerves do not have the
  protection of the verebral column or skull.
• Instead they are wrapped up in CT much like mms
  fibers and most of the time, they hide under
  mms., which protect them from trauma.