Your Federal Quarterly Tax Payments are due April 15th Get Help Now >>

CRANIAL NERVES I by gox54152

VIEWS: 26 PAGES: 38

									CRANIAL NERVES I.


  OUTLINE

  I. HISTORY OF ANATOMY

  II. CLASSIFICATION OF
  TYPES OF NEURONS IN
  CRANIAL NERVES
SKELETON FROM PERSIAN
MANUSCRIPT IN 1300;
PRIOR TO DISSECTION
SEE HUMAN ANATOMY
IN WARS
PREGNANT WOMAN
GERMANY ABOUT 1400
LATE MIDDLE AGES
DISSECT ONLY
CRIMINALS
FEW FEMALES;
EMBRYO THOUGHT OF
AS LITTLE PERSON
AROUND
1400-1500
ANATOMY
TAUGHT IN
UNIVERSITIES
WITH
DISSECTION
VESALIUS
(1514-1564)

ANATOMISTS
BECAME
ARTISTS
                     ANDREAS
           DELTOID   VESALIUS
                     1543
BRACHIO-
RADIALIS             UNIVERSITY
                     OF PADUA
LEONARDO
DA VINCI
1452-1518

ARTISTS
BECAME
ANATOMISTS
DRAWINGS
OF
FETUS
IN
SITU
                            STUDY
                            ANATOMY
                            TO MORE
                            ACCURATELY
                            REPRESENT
                            HUMAN
                            BODY
                            IN
                            ART

DA VINCI DRAWING OF SKULL
http://www.nlm.nih.gov/




 History of Medicine Division
BARTOLOMEO EUSTACHIO 1510?-1574




        - AUDITORY TUBE =
        EUSTACHIAN TUBE
        - DISSECT BODY IN FEW DAYS
        - DRAWING IS MADE
        FROM MEMORY OF
        MANY DISSECTIONS
    ENLARGEMENT
    OF BRACHIAL
    PLEXUS



M
ENLARGEMENT
OF BRAIN

OPTIC CHIASM
V1, V2, V3
          CRANIAL NERVES

             A. contain inflow/outflow of brain;
CRANIAL
NERVES       spinal nerves contain inflow/outflow
             of spinal cord.
             B. contain types of similar to those
             found in spinal nerves; ex. sensory
             axons to skin.
             C. contain types of neurons not found
SPINAL
             in spinal nerves; ex. taste fibers.
NERVES
             D. Many cranial nerves contain more
             than one type of neuron.
             E. To analyze types of neurons in
             different cranial nerves, system of
             classification based upon anatomy,
             embryology and homologies; TYPES
             OF NEURONS are called
             FUNCTIONAL COMPONENTS
II. BASIS OF CLASSIFICATION - three letter system.

         A. First letter
                   G = General = types of neurons found both in
spinal nerves and cranial nerves.
                   S = Special = types of neurons only found in
cranial nerves not spinal nerves.
         B. Second letter
                   S = Somatic = types of neurons innervating
structures derived from somites.
                   V = Visceral = types of neurons innervating gut,
structures derived from or associated with gut and branchial
arches; also vascular system, smooth muscle, internal organs and
glands.
         C. Third letter
                   A = Afferent = sensory neurons.
                   E = Efferent = motor neurons to skeletal and
smooth muscle; also secretomotor neurons to glands.
 III. CLASSIFICATION OF INNERVATION AS
 FUNCTIONAL COMPONENTS
          A. General Innervation - like spinal cord
                    1. GSE (General Somatic Efferent) - motor to somatic
voluntary skeletal muscles (derived from somites).
                    2. GSA (General Somatic Afferent) - sensory to skin,
joints, muscle and tendon receptor endings, nasal and oral cavity.
                    3. GVE (General Visceral Efferent) = Autonomic
Efferents - motor to smooth muscles in general and smooth muscles of
skin (arrector pilae muscles) and blood vessels, secretomotor to glands.
                    4. GVA (General Visceral Afferent) - sensory to gut
and its derivatives, pharynx, blood vessels, glands and internal organs.

          B. Special Innervation - only found in head.
                    1. SSA (Special Somatic Afferent) - special senses
of vision, auditory sensation and vestibular apparatus.
                    2. SVA (Special Visceral Afferents) - chemical
senses of taste and by analogy smell.
                    3. SVE (Special Visceral Efferents) - motor to
voluntary skeletal muscles derived from branchial arches (these muscles
develop in association with pharynx, which is rostral end of gut and
therefore visceral).
CRANIAL NERVES


             I. Olfactory
            II. Optic
            III. Oculomotor
            IV. Trochlear
            V. Trigeminal
            VI. Abducens
            VII. Facial
            VIII. Vestibulo-cochlear
            IX. Glossopharyngeal
            X. Vagus
            XI. Accessory
            XII. Hypoglossal
          GSE - General Somatic Efferents
      motor to skeletal muscle derived from
      somites; only two groups in head

Preotic                            1) Preotic myotomes
          Occipital                (somitomeres) form
                                   extrinsic muscles
                                   of eye:
                                   III - Oculomotor,
                                   IV - Trochlear,
                                   VI - Abducens.

                                   2) Occipital myotomes
                                   form muscles of tongue
                                   - XII
      6 weeks            8 weeks   Hypoglossal N.
         GSA - General Somatic Afferents
sensory to skin, ORAL cavity, NASAL cavity, joints, muscles



                                  ALMOST ALL
                                  TRIGEMINAL V
                                  EXCEPTION:
                                  SKIN OF OUTER EAR
                                  ALSO
                                  1) VII- FACIAL
                                  2) IX - GLOSSO-
                                  PHARYNGEAL
                                  3) X - VAGUS


      BELL'S PALSY (VII) - PARALYSIS OF FACIAL MUSCLES; IN
      RECOVERY, PATIENTS COMPLAIN OF EARACHES
SENSORY CELL BODIES IN DORSAL ROOT GANGLIA
IN SPINAL CORD


DORSAL
ROOT
GANGLION
SENSORY GANGLIA ARE ATTACHED TO CRANIAL NERVES


    - cell bodies of
    sensory neurons
    in Trigeminal Nerve
    are in
    Trigeminal
    (Semilunar)
    Ganglion




   Cell bodies of sensory neurons in VII (Facial Nerve) in
   Geniculate Ganglion
       GVE - General Visceral Efferents




SYMPATHETIC - thoraco-lumbar
PARASYMPATHETICS - cranio-sacral - ganglia close to
    target organ
SYMPATHETICS IN THORAX, ABDOMEN




                            Thoraco-
                            Lumbar
                            T1-T12,
                            L1, L2
SYMPATHETICS TO HEAD



                  - First neuron
                  Out T1, T2

                  Ascends
                  Chain
SYMPATHETICS TO HEAD




                 Second neuron In
                 Superior
                 Cervical Ganglia


                 Joins Plexus on
                 Internal and External
                 Carotid Arteries
                 1) Unnamed branches
                 2) Few named branches
                 Ex. Deep Petrosal N.
      PARASYMPATHETICS - IN CRANIAL NERVES


III


VII                                      +palate

IX
X
         GVA - General Visceral Afferents
         Sensory to Pharynx and derivatives


                                   All Pharynx is GVA
Nasal                              In 3 Cranial Nerves
Cavity
GSA
                         NASOPHARYNX - VII

Oral                       OROPHARYNX - IX
Cavity
GSA
                           LARYNGOPHARYNX - X
    SSA - Special Somatic Afferents

Special senses only found in head - SSA =
vision II, hearing and balance VIII



II-
OPTIC
NERVE

fibers
cross at
optic
chiasm
SSA - Special Somatic Afferents

                      VIII -
                      VESTIBULO-
                      COCHLEAR

                      to 1) cochlea - hearing
                      2) semicircular canals -
                      balance
               VIII
                      in petrous part of
                      temporal bone
     SVA - Special Visceral Afferents

Chemical senses - Taste and Smell

                I - OLFACTORY NERVE
     SVA - Special Visceral Afferents
  Chemical Sense - TASTE - in three cranial nerves



                               X - VAGUS -
                               ant. to epiglottis

                               IX - GLOSSO-
                               PHARYNGEAL
TONGUE
                               post. 1/3 of tongue

                               VII - FACIAL -
                               ant. 2/3 of tongue
        SVE - Special Visceral Efferents
   - motor to voluntary skeletal muscles derived from
   branchial arches
   - visceral because develop in pharynx then migrate




First -                Third                    Sixth
           Second -                   Fourth
Trigeminal Facial      Glosso-                  Accessory
                                      Vagus
V                      pharyngeal               XI
           VII                        X
                       IX
 III. CLASSIFICATION OF INNERVATION AS
 FUNCTIONAL COMPONENTS
          A. General Innervation - like spinal cord
                    1. GSE (General Somatic Efferent) - motor to somatic
voluntary skeletal muscles (derived from somites).
                    2. GSA (General Somatic Afferent) - sensory to skin,
joints, muscle and tendon receptor endings, nasal and oral cavity.
                    3. GVE (General Visceral Efferent) = Autonomic
Efferents - motor to smooth muscles in general and smooth muscles of
skin (arrector pilae muscles) and blood vessels, secretomotor to glands.
                    4. GVA (General Visceral Afferent) - sensory to gut
and its derivatives, pharynx, blood vessels, glands and internal organs.

          B. Special Innervation - only found in head.
                    1. SSA (Special Somatic Afferent) - special senses
of vision, auditory sensation and vestibular apparatus.
                    2. SVA (Special Visceral Afferents) - chemical
senses of taste and by analogy smell.
                    3. SVE (Special Visceral Efferents) - motor to
voluntary skeletal muscles derived from branchial arches (these muscles
develop in association with pharynx, which is rostral end of gut and
therefore visceral).
                Before you Leave – Make Incision
                Around Head, Above Ears




Peel Muscles
From Skull On
Back Of Neck
Expose Joint
Occip-C1

								
To top