1. STRUCTURAL ORGANIZATION OF
NERVOUS SYSTEM
INTRODUCTION

2. 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

3. NERVOUS SYSTEM
• DIVISION OF NERVOUS SYSTEM
• NERVOUS SYSTEM IS DIVIDED
• STRUCTURALLY INTO---- CNS
• ---- PNS
• FUNCTIONALLY INTO---- SOMATIC
• ---- AUTONOMIC

7. 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

9. 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

10. NERVOUS SYSTEM
• NEUROGLIA
• NONEXCITABLE
• FORM A MAJOR COMPONENT OF NERVOUS
TISSUE
• SUPPORT, INSULATE AND NOURISH THE
NEURONS

11. NERVOUS SYSTEM
• NEUROGLIA [ CONTD ]
• IN THE CNS INCLUDE---
• OLIGODENDROCYTES
• ASTROCYTES
• EPENDYMAL CELLS
• MICROGLIA
• IN THE PNS INCLUDE---
• SATELLITE CELLS
• SCHWANN CELLS

12. 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

13. 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

14. 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

15. NERVOUS SYSTEM
• MENINGES [CONTD ]
• THREE LAYERS---
• PIA MATER—INNERMOST
• ARACHNOID MATER –MIDDLE
• DURA MATER—OUTERMOST
• CSF PRESENT B/W ARACHNOID AND PIA
MATER

18. 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

19. 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

20. NERVOUS SYSTEM
• PNS[CONTD]
• PERIPHERAL NERVES
• CRANIAL--- 12 PAIRS 12th PAIR ARISES MOSTLY
FROM THE SUPERIOR PART OF SPINAL CORD
• SPINAL--- 31 PAIRS
• C—8
• T---12
• L ---5
• S ---5
• CO-1

21. 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

22. 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

23. 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

24. 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

25. MAJOR DIVISIONS OF CNS
• BRAIN
• PRESENT IN THE CRANIAL CAVITY
• SURROUNDED BY THREE LAYERS OF
MENINGES
• DIVIDED INTO THREE MAJOR DIVISIONS---
• HINDBRAIN
• MIDBRAIN
• FOREBRAIN

27. HIND BRAIN
• DIVIDED INTO---
• MEDULLA OBLONGATA
• PONS
• CEREBELLUM

28. 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

29. 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

30. 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

31. 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

32. HINDBRAIN
• CAVITY OF HINDBRAIN IS 4th VENTRICLE
• 4th VENTRICLE CONNECTED TO 3rd VENTRICLE
BY THE CEREBRAL AQUEDUCT
• CONTINUOUS INFERIORLY WITH THE CENTRAL
CANAL OF SP CORD
• COMMUNICATES WITH SUBARACHNOID
SPACE THROUGH THREE OPENINGS IN THE
ROOF

33. MIDBRAIN
• NARROW PART THAT CONNECTS THE
FOREBRAIN TO THE HINDBRAIN
• CAVITY IS THE CEREBRAL AQUEDUCT
• CONTAINS MANY NUCLEI AND ASCENDING
AND DESENDING FIBRES

34. DIENCEPHALON
• HIDDEN FROM THE SURFACE OF THE BRAIN
• CONSISTS OF ---
• DORSAL THALAMUS
• VENTRAL HYPOTHALAMUS
• ITS CAVITY IS 3rd VENTRICLE
• THALAMUS IS PRESENT ON EITHER SIDE OF
THE 3rd VENTRICLE

37. 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

38. 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

39. 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

40. CEREBRUM
• CAVITY OF CEREBRAL HEMISPHERES IS
LATERAL VENTRICLE
• LATERAL VENTRICLE COMMUNICATES WITH
THE 3rd VENTRICLE THROUGH
INTERVENTRICULAR FORAMEN

41. 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

44. 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

45. 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

46. 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

47. SPINAL GANGLIA
• THEY ARE SENSORY GANGLIA
• SITUATED ON THE POSTERIOR ROOT OF EACH
SPINAL NERVE
• FUSIFORM SWELLINGS