nervous_ by lanyuehua

VIEWS: 12 PAGES: 56

									I. Functions:
     a.) Maintains a steady state
         1. with fast response =
          ELECTRICAL signals
         2. with slow response =
         CHEMICAL (HORMONES)
         signals
         to the ENDOCRINE system
b.) Interprets SENSORY information
 Lab : Two-point Threshold Test

• Purpose : To see if the distribution of
  Touch Receptors is an indication of size
  of the area of brain responsible for this
  reception.
• Areas tested = Index finger, forearm, back
  of neck, back of calf, palm of hand, and
  lower lip
               Background
• The more touch receptors the better able
  you are to distinguish 2 touch points.
• We want to verify the fact that if you have
  more touch receptors in an area of the body
  You must have the larger the area of the
  brain to receive information from that area.
      Getting to a hypothesis:
• Pick one area you think has the most touch
  receptors. Then pick one area you think has
  the least touch receptors
  – Index finger, forearm, back of neck, back of
    calf, palm of hand, and lower lip
               Hypothesis
• I think that the most sensitive area of my
  body is the _____ and the least sensitive are
  is the ________
• I think the largest sensory area of my brain
  controls the _________ and the smallest
  sensory area controls the _______
                Procedure
• Conduct a two point threshold test on the
  – Index finger, forearm, back of neck, back of
    calf, palm of hand, and lower lip
  – Subject closes eyes while experimenter touched
    areas using two points at decreasing distance
    apart.
  – Subject reports a single or double sensation
  – Stop when subject can no longer distinguish 2
    points.
               Observations
Area     100   50 40 30 20 10 7  5  2
         mm    mm mm mm mm mm mm mm mm
finger
arm
neck
calf
palm
lip
              Conclusion
• Which area was most and least sensitive?
  How do you know?
• Which somatic area is the largest and
  smallest? How do you know?
• Evaluate hypothesis
• Explain what you learned
        What is the homunculus?
• http://faculty.washington.edu/chudler/flash/hom.html
• Homunculus animation
• Body on the left side is the motor homunculus. The bigger
  the body parts more brainpower controls it.
• The body half on the right is sensory homunculus.
• Since the left side of brain controls the right side of the
  body and vise versa, clicking on an area on the left side of
  the body will trigger an area on the right side of the brain.
  To compare different areas, you may click on different
  parts of the picture.
     Online link for Homunculus

• http://www.cs.uta.fi/~jh/homunculus.html
• Be sure to include this information in the
  what I learned section of you lab report
c.) provides higher MENTAL
    functioning
d.) produces EMOTIONAL response
e.) activates the MUSCLES for
    movement
                   2           3
          1
                           4


13                                 5

                                       6
12

                                       7
     11

          10           8
               9
II. Divisions:
A.By structure:
(TWO DIVISIONS)
1. CENTRAL nervous system CNS
    a.) BRAIN
    (about 3 pounds)
    b.) SPINAL
        NERVE
        cord (43-45cm)
2.PERIPHERAL
nervous system
  PNS
  a.) NERVES
     (neurons)
    b.) supporting
   NERVOUS tissue
         (glia)
B. By Functions:
(TWO DIVISIONS of PNS)
1.) SOMATIC division
    a.) Regulation of CONSCIOUS or
        VOLUNTARY actions
b.) pathway : ONE nerve from
          CNS to MUSCLE




b.) pathway : ONE nerve from
CNS to MUSCLE
2.)AUTONOMIC division
    a.) Regulates AUTOMATIC or
        INVOLUNTARY actions
b.) pathway :TWO nerves from
          CNS to MUSCLE or GLAND
c.) further divisions:(TWO)
1.) Parasympathetic division:

 a.)PEACEFUL,
    housekeeping division

 b.) in CONTROL most of
     the time
c.) neutotransmitter =
    ACETYLCHOLINE.
2.) Sympathetic division:

 a.) STRESSFUL, action
     division
 b.) Usually speeds up
      actions like HEART RATE,
      BLOOD PRESSURE,
      BREATHING RATE
c.) Neurotransmitter =

NOREPINEPHRINE
callosum

           hypothalamus
             Lateral ventricle
                        1 & 2




               third ventricle




                 Pituitary
                 gland
Protection of the CNS
I. Nervous tissue is very SOFT and
 MUSHY. (consistency of WELL
          cooked OATMEAL)
II. The brain and SPINAL cord are
    protected THREE ways.
     a.) BONE surrounds the
            BRAIN and SPINAL cord.
b.)THREE membranes are
   found under the bone
c.) A watery
cushion is found
within the         3rd
 MEMBRANES -       ventricle


CEREBRAL
                               4th ventricle
SPINAL
 fluid (CSF)
III. The Meninges:
      a.) The Dura MATER
           1.) the outermost membrane
           2.) DOUBLE layer
           3.) Leathery and VERY TOUGH
b.) The ARACHNOID mater
          1.) the MIDDLE membrane
          2.) SPIDERY and weblike
          3. ) CSF circulates inside this
          layer in a space called the
          SUB-ARACHNOID space.
c.) The PIA mater
          1.) The INNERMOST membrane
          2.) very THIN and delicate
          3. ) clings TIGHTLY to each fold of
                the brain

     Without
                                       With
     Pia mater
                                       Pia mater
d.) MENINGITIS - inflammation of the
                  meninges
        1.) diagnosed by a SPINAL tap
        2.) bacteria treated with
            ANTIBIOTICS
        3.) can be fatal
        4.) symptoms = STIFF NECK and
               SORE THROAT
Sagittal   Lateral ventricle
IV. Cerebrospinal fluid: (125-150 ML)
     A. Very similar to PLASMA
 (thick, viscous, sticky, salty to the taste)
     B. Produced inside the BRAIN
1.) the brain has four cavities called
    VENTRICLES
      a.) two LATERAL ventricles (one
           in each cerebral HEMISPHERE)
      b.) a third and FOURTH ventricle
             deep inside the brain
2.) in each cavity is a cluster of
blood vessels called
CHOROID PLEXUS that makes
fluid. (produces 500 ml / day)
C.) circulates around BRAIN and
SPINAL CORD (protect brain and
 decreases pressure on the brain
stem also circulates hormones)
D.) drains into the BLOOD STREAM
1. At the top of the brain projections
from arachnoid space called
arachnoid villi control rate of
drainage

2. Entrance to blood
stream called
SUPERIOR
SAGITTAL SINUS
E. ) Obstructions like TUMORS
sometimes occur
       1.)PRESSURE builds up
       2.) CIRCULATION hampered
3.) HYDROCEPHALY occurs
(water on the brain)
4.) Can occur in utero
5.) Blockage must be SURGICALLY
 removed and drainage
  must be reestablished.
                             Sagittal   Lateral ventricle

Of lateral ventricle
                       F. Circulation pattern
              Circulation patters
• The ________________________ __________________
                   Choroid Plexus
  (1) of the _______________
                        Lateral Ventricle
• __________________________(2) forms the cerebral
  spinal fluid. This fluid leaves the lateral ventricles through
  the ________________________
         Interventricular Foramen
  ____________________(3)
• It enters the ______________
                      Third Ventricle
  _______________________(4) where more cerebral spinal
  fluid is added by the ______________
                                     Choroid plexus
  _________________(5) of the third ventricle.
                  Circulation pattern continue
• Next the fluid travels down the _____________________
                                      Cerebral Aqueduct
  __________________(6)
• into the ____________________ ______________ (7).
                     Fourth ventricle
  Here the _______________
• _____________________ (8) of the fourth ventricle adds
        Choroid Plexus
  still more cerebral spinal fluid. The fluid can leave the
  fourth ventricle through one of three holes. There are two
  _____________________ ___________________(9) and
                 Lateral Foramen
  one _______________
         Median Aperture
• ______________________ (10).
            Circulation pattern continued
• Now the fluid enters the ________-_____________
                                        Sub-Arachnoid Space
  _________________ (11). While it is in this space it
  circulates around the brain and the spinal cord. Eventually
  most of the cerebral spinal fluid is absorbed into the
  venous blood at the _______________________
                                  Arachnoid Villi

• ____________ (12). These villi are collection points that
  direct the cerebral spinal fluid into the
  _____________________ ________________
                Superior Sagittal Sinus
  ______________ (13).
• Approximately ________ml of cerebrospinal fluid is
                        500
  produced and absorbed each day.

								
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