STRUCTURAL ORGANIZATION OF NERVOUS SYSTEM INTRODUCTION
NERVOUS SYSTEM NERVOUS SYSTEM AND ENDOCRINE SYSTEM CONTROL THE FUNCTIONS OF THE BODY NERVOUS SYSTEM ENABLES THE BODY TO REACT TO CONTINUOUS CHANGES IN ITS INTERNAL AND EXTERNAL ENVIRONMENT CONTROLS AND INTEGRATES THE VARIOUS ACTIVITIES OF THE BODY LIKE CIRCULATION AND RESPIRATION
NERVOUS SYSTEM DIVISION OF NERVOUS SYSTEM NERVOUS SYSTEM IS DIVIDED STRUCTURALLY INTO---- CNS ---- PNS FUNCTIONALLY INTO---- SOMATIC ---- AUTONOMIC
NERVOUS SYSTEM CELLS OF NERVOUS SYSTEM CONSISTS OF TWO MAIN TYPES OF CELLS 1 NEURONS 2 NEUROGLIA NEURONES STRUCTURAL AND FUNCTIONAL UNITS OF NERVOUS SYSTEM COMPOSED OF A CELL BODY &PROCESSES
NERVOUS SYSTEM NEURONES [CONTD ] PROCESSES ARE— DENDRITES & -- -AXONS MYELIN CONSISTS OF LAYERS OF LIPIDS AND PROTEINS FORMS A SHEATH AROUND SOME AXONS WHICH INCREASES THE VELOCITY OF IMPULSE CONDUCTION
NERVOUS SYSTEM NEUROGLIA NONEXCITABLE FORM A MAJOR COMPONENT OF NERVOUS TISSUE SUPPORT, INSULATE AND NOURISH THE NEURONS
NERVOUS SYSTEM NEUROGLIA [ CONTD ] IN THE CNS INCLUDE--- OLIGODENDROCYTES ASTROCYTES EPENDYMAL CELLS MICROGLIA IN THE PNS INCLUDE--- SATELLITE CELLS SCHWANN CELLS
NERVOUS SYSTEM CNS CONSISTS OF BRAIN AND SPINAL CORD MAIN FUNCTIONS 1 INTEGRATE AND COORDINATE INCOMING AND OUTGOING NEURAL SIGNALS 2 CARRY OUT HIGHER MENTAL FUNCTIONS SUCH AS THINKING AND LEARNING
NERVOUS SYSTEM CNS [ CONTD ] NUCLEUS ---COLLECTION OF NERVE CELL BODIES IN THE CNS TRACT--- ABUNDLE OF NERVE FIBRES[AXONS] CONNECTING NEIGHBOURING AND DISTANT NUCLEI OF THE CNS BRAIN AND SPINAL CORD COMPOSED OF GREY MATER & WHITE MATER
NERVOUS SYSTEM CNS [ CONTD ] GREY MATER FORMED BY NERVE CELL BODIES WHITE MATER FORMED BY INTERCONNECTING FIBRE TRACT SYSTEM MENINGES MEMBRANOUS LAYERS THAT COVER THE BRAIN AND SPINAL CORD
NERVOUS SYSTEM MENINGES [CONTD ] THREE LAYERS--- PIA MATER—INNERMOST ARACHNOID MATER –MIDDLE DURA MATER—OUTERMOST CSF PRESENT B/W ARACHNOID AND PIA MATER
NERVOUS SYSTEM PNS CONSISTS OF NERVE FIBRES AND NERVE CELL BODIES OUTSIDE THE CNS THAT CONDUCT IMPULSES TO OR AWAY FROM THE CNS PNS MADE UP OF NERVES THAT CONNECT THE CNS WITH PERIPHERAL STRUCTURES PERIPHERAL NERVE IS A BUNDLE OF NERVE FIBRES[AXONS] IN THE PNS GANGLION IS A COLLECTION OF NERVE CELL BODIES OUTSIDE THE CNS
NERVOUS SYSTEM PNS CONSISTS OF NERVE FIBRES AND NERVE CELL BODIES OUTSIDE THE CNS THAT CONDUCT IMPULSES TO OR AWAY FROM THE CNS PNS MADE UP OF NERVES THAT CONNECT THE CNS WITH PERIPHERAL STRUCTURES PERIPHERAL NERVE IS A BUNDLE OF NERVE FIBRES[AXONS] IN THE PNS GANGLION IS A COLLECTION OF NERVE CELL BODIES OUTSIDE THE CNS
NERVOUS SYSTEM PNS[CONTD] PERIPHERAL NERVES CRANIAL--- 12 PAIRS 12 th PAIR ARISES MOSTLY FROM THE SUPERIOR PART OF SPINAL CORD SPINAL--- 31 PAIRS C—8 T---12 L ---5 S ---5 CO-1
MAJOR DIVISIONS OF CNS SPINAL CORD PRESENT WITHIN THE VERTEBRAL CANAL SURROUNDED BY THREE LAYERS OF MENINGES ROUGHLY CYLINDRICAL BEGINS AT FORAMEN MAGNUM INFERIORLY TAPERS OFF INTO CONUS MEDULLARIS TERMINATES AT THE LOWER BORDER OF L1 IN THE ADULT
MAJOR DIVISIONS OF CNS SPINAL CORD [CONTD ] FILUM TERMINALE IS A PROLONGATION OF PIA MATER –EXTENDS FROM THE APEX OF CONUS MEDULLARIS AND IS ATTACHED TO THE BACK OF COCCYX 31 PAIRS OF SPINAL NERVES ATTACHED TO THE SP CORD EACH SPINAL NERVE ATTACHED BY TWO ROOTS--- ANTERIOR OR MOTOR ROOT AND POSTRIOR OR SENSORY ROOT POSTERIOR ROOT GANGLION PRESENT ON POSTERIOR ROOT CELLS IN THE GANGLION GIVE RISE TO CENTRAL AND PERIPHERAL PROCESSES
MAJOR DIVISIONS OF CNS STRUCTURE OF SPINAL CORD COMPOSED OF-- INNER CORE OF GREY MATER SURROUNDED BY—OUTER CORE OF WHITE MATER GREY MATER IN CROSS SECTION IS H SHAPED WITH ANTERIOR AND POSTERIOR HORNS UNITED BY A THINLAYER OF GREY COMMISSURE CONTAINING THE CENTRAL CANAL
MAJOR DIVISIONS OF CNS STRUCTURE OF SP CORD [CONTD ] IN THE THORACIC SEGMENT LATERAL HORNS ARE ALSO PRESENT WHITE MATER DIVIDED INTO--- ANTERIOR WHITE COLUMN LATERAL WHITE COLUMN POSTERIOR WHITE COLUMN
MAJOR DIVISIONS OF CNS BRAIN PRESENT IN THE CRANIAL CAVITY SURROUNDED BY THREE LAYERS OF MENINGES DIVIDED INTO THREE MAJOR DIVISIONS--- HINDBRAIN MIDBRAIN FOREBRAIN
HIND BRAIN DIVIDED INTO--- MEDULLA OBLONGATA PONS CEREBELLUM
MEDULLA OBLONGATA CONICAL IN SHAPE CONNECTS THE PONS TO THE SPINAL CORD CONTAINS A NUMBER OF NUCLEI SERVES AS A PASSAGE FOR ASCENDING AND DESCENDING TRACTS
PONS PRESENT ON THE ANTERIOR SURFACE OF THE CEREBELLUM CONNECTS THE MIDBRAIN TO THE MEDULLA HAS LARGE NUMBER OF TRANSVERSE FIBRES CONNECTING THE TWO CEREBELLAR HEMISPHERES CONTAINS MANY NUCLEI AND ASCENDING AND DESCENDING NERVE FIBRES
CEREBELLUM PRESENT IN THE POSTERIOR CRANIAL FOSSA THE TWO HEMISPHERES CONNECTED BY VERMIS CONNECTED TO THE MIDBRAIN BY—SUPERIOR CEREBELLAR PEDUNCLES CONNECTED TO THE PONS BY---MIDDLE CEREBELLAR PEDUNCLE CONNECTED TO THE MEDULLA BY---INFERIOR CEREBELLAR PEDUNCLE
CEREBELLUM SURFACE LAYER CALLED THE CORTEX CORTEX COMPOSED OF GREY MATER CORTEX THROWN INTO FOLDS/FOLIA SEPARATED BY TRANSVERSE FISSURES INTRACEREBELLAR NUCLEI ARE FOUR ON EACH SIDE ---DENTATE ---EMBOLIFORM ---GLOBOSE ---FASTIGIAL
HINDBRAIN CAVITY OF HINDBRAIN IS 4 th VENTRICLE 4 th VENTRICLE CONNECTED TO 3 rd VENTRICLE BY THE CEREBRAL AQUEDUCT CONTINUOUS INFERIORLY WITH THE CENTRAL CANAL OF SP CORD COMMUNICATES WITH SUBARACHNOID SPACE THROUGH THREE OPENINGS IN THE ROOF
MIDBRAIN NARROW PART THAT CONNECTS THE FOREBRAIN TO THE HINDBRAIN CAVITY IS THE CEREBRAL AQUEDUCT CONTAINS MANY NUCLEI AND ASCENDING AND DESENDING FIBRES
DIENCEPHALON HIDDEN FROM THE SURFACE OF THE BRAIN CONSISTS OF --- DORSAL THALAMUS VENTRAL HYPOTHALAMUS ITS CAVITY IS 3 rd VENTRICLE THALAMUS IS PRESENT ON EITHER SIDE OF THE 3 rd VENTRICLE
CEREBRUM LARGEST PART OF THE BRAIN CONSISTS OF TWO HEMISPHERES CONNECTED BY COROUS CALLOSUM HEMISPHERES SEPARATED BY LONGITUDINAL FISSURE CORTEX IS THE SURFACE LAYER CORTEX COMPOSED OF GREY MATER CORTEX THROWN INTO FOLDS –THE SULCI
CEREBRUM GYRI SEPARATED BY FISSURES OR SULCI LARGE SULCI ARE USED TO SUBDIVIDE EACH HEMISPHERES INTO LOBES--- FRONTAL LOBE PARIETAL LOBE OCCIPITAL LOBE TEMPORAL LOBE
CEREBRUM CENTRAL CORE OF WHITE MATER CONTAINS LARGE MASSES O0F GREY MATER CORONA RADIATA—FAN SHAPED COLLECTION OF NERVE FIBRES CORONA RADIATA CONVERGES ON THE BASAL NUCLEI AND PASSES B/W THEM AS INTERNAL CAPSULE CAUDATE NUCLEUS IS MEDIAL TO INTERNAL CAPSULE LENTIFORM NUCLEUS IS LATERAL TO INTERNAL CAPSULE
CEREBRUM CAVITY OF CEREBRAL HEMISPHERES IS LATERAL VENTRICLE LATERAL VENTRICLE COMMUNICATES WITH THE 3 rd VENTRICLE THROUGH INTERVENTRICULAR FORAMEN
MAJOR DIVISIONS OF PNS 12 PAIRS OF CRANIAL NERVES---LEAVE THE BRAIN AND PASS THROUGH THE FORAMINA IN THE SKULL 31 PAIRS OF SPINAL NERVES---LEAVE THE SPINAL CORD AND PASS THROUGH INTERVERTEBRAL FORAMINA
SPINAL NERVES EACH SPINAL NERVE IS CONNECTED TO THE SPINAL CORD BY TWO ROOTS--- ANTERIOR ROOT—CONSISTS OF EFFERENT/MOTOR NERVE FIBRES CARRYING IMPULSES AWAY FROM THE CNS—CELL BODIES IN THE ANTERIOR GREY HORN OF SP CORD POSTERIOR ROOT---CONSISTS OF AFFERENT/SENSORY NERVE FIBRES CARRYING IMPULSES TO THE CNS-- CELL BODIES IN THE POST ROOT GANGLION
SPINAL NERVES EACH SPINAL NERVE IS AMIXED NERVE CONTAINING BOTH MOTOR AND SENSORY FIBRES IN THE UPPER CERVICAL REGION THE ROOTS ARE SHORT AND ALMOST HORIZONTAL LENGTH OF THE ROOTS INCREASES FROM ABOVE DOWNWARDS THE ROOTS OF LUMBER AND SACRAL NERVES FORM A VERTICAL LEASH CALLED THE CAUDA EQUINA
SPINAL NERVE EACH SPINAL NERVE IS A SHORT TRUNK AFTER EMERGING FROM THE INTERVERTEBRAL FORAMEN IT DIVIDES INTO – ANTERIOR RAMUS AND SUPPLIES THE MUSCLES AND SKIN OVER THE ANTEROLATERAL BODY WALL ANTERIOR RAMI JOIN ONE ANOTHER AT THE ROOT OF THE LIMBS TO FORM NERVE PLEXUSES CERVICAL AND BRACHIAL PLEXUSES AT THE ROOT OF UPPER LIMB LUMBER AND SACRAL PLEXUSES AT THE ROOT OF LOWER LIMB POSTERIOR RAMUS –PASSES TO THE BACK AND SUPPLIES THEMUSCLES AND SKIN OF THE BACK
SPINAL GANGLIA THEY ARE SENSORY GANGLIA SITUATED ON THE POSTERIOR ROOT OF EACH SPINAL NERVE FUSIFORM SWELLINGS