PNS I

PARASYMPATHETIC NERVOUS SYSTEM

IS NECESSRAY TO SUSTAIN LIFE

SYMPATHETIC NERVOUS SYSTEM

IS EXPENDIBLE AND MAY BE CUT WITH NO LOSS TO LIFE

CRANIAL NERVES

CN III(3), IV(4), VI(6), AND XII(12) CARRY SOMATIC EFFERENT FIBERS

O INNERVATE SKELETAL MUSCLES OF THE HEAD DERIVED FROM SOMITES

CN V(5), VII(7), IX(9), AND X(10) CARRY BRANCHIAL EFFERENT FIBERS

O INNERVATE CARINAL MUSCLES OF BRANCHIAL ARCH ORIGIN

O BUT FOLLEWS THE SAME SCHEME AS SOMATIC EFFERNT PATHWAYS

VOLUNTARY MOTOR COMPONENTS

FEATURE TWO SETS OF NEURONS – UPPER MOTOR NEURONS AND LOWER MOTOR NEURONS

GENERAL SENSORY COMPONENTS

FEATURE THREE SETS OF NEURONS –PRIMARY (1), SECONDARY (2), AND TERTIARY (3)

CRANIAL NERVES

PRIMARY (1) O LOCATED WITHIN SENSORY GANGLIA – SWELLINGS OF

CRANIAL NERVES WITH SENSORY COMPONENTS –CN V, VII, IX, AND X

SECONDARY (2)O WITH IN THE BRAINSTEM

O AXONS DESSUCATE

TERTIARY (3)O 2 NEURON SYNAPSES AT THALAMUS

O CONTINUES TOWARDS THE SENSORY CORTEX

THE ORIGINS OF CRANIAL NERVES

CNI – OLFACTORY NERVE

O ARISES FROM THE OLFACTORY TRIGON ON THE INFERIOR SURFACE OF THE FOREBREAIN

CN II – OPTIC NERVE

O ORIGINATES FROM THE LATERAL GENICULATE BODIES AT THE BASE OF THE DIENCEPHALON.

CN III – OCULOMOTOR NERVE

O ARISES FROM THE CEREBRAL PEDUNCLES (INTERPUDENCULAR FOSSA) OF THE MIDBRAIN.

CN IV – TROCHLEAR NERVE

O ARISES FROM THE INFERIOR COLLICULUS ON THE DORSAL ASPECT OF THE MIDBRAIN

CN V – TRIGEMINAL NERVE

O EMERGES FROM THE LATERAL ASPECTS OF THE MIDPONS

CN VI – ABDUCENT NERVE

O LEAVES THE BRAIN IN THE INFERIOR PONTINE SULCUS

CN VII – FACIAL NERVE

O EMERGES FROM THE BRAINSTEM AT THE INFERIOR PONTINE SULCUS IN LINE WITH THE POST-OLIVARY SULCUS OF THE MEDULLA

CN VIII – VESTIBULOCOCHLEAR NERVE

O ARISES FROM THE SULCU BETWEEN THE PONS AND THE MEDULLA, AND TRAVEL LATERALLY AT THE CEREBELLO-PONTINE ANGLE

CN IX – GLOSSOPHARYNGEAL NERVE

O EMERGES FROM THE MEDULLA BETWEEN THE OLIVE AND THE INFERIOR CEREBELLAR PEDUNCLE

CN X – VAGUS NERVE

O LEAVES THE MEDULLA FROM THE POST-OLIVARY SULCUS BY MULTIPLE ROOTLETS

CN XI – SPINAL ACCESSORY NERVE

O A. SPINAL ROOT – ACCESSORY NUCLEUS WITHIN LATREAL VENTRAL HORNS OF C1-C6 CERVICAL SEGMENTS

O B. CRANIAL ROOT – NUCLEUS AMBIGUUS IN THE MEDULLA

CN XII – HYPOGLOSSAL NERVE

O NUMEROUS ROOTLETS ARIASE FROM PRE-OLIVARY SULCUS OF THE MEDULLA