CENTRAL NERVOUS SYSTEM THE SPINAL CORD. FUNCTIONS OF THE SPINAL CORD CONDUCTS NERVE IMPUSLES TO AND FROM THE BRAIN PROCESSES SENSORY INFORMATION (LIMITED)

CENTRAL NERVOUS SYSTEM

THE SPINAL CORD

FUNCTIONS OF THE SPINAL CORD

• CONDUCTS NERVE IMPUSLES TO AND FROM THE BRAIN

• PROCESSES SENSORY INFORMATION (LIMITED)

DEVELOPMENT OF SPINAL CORD

• UNTIL THIRD FETAL MONTH, SPINAL CORD IS AS LONG AS THE VERTEBRAL COLUMN

• VETERBRAL COLUMN GROWS FASTER

FILIUM TERMINALE

CONUS MEDULLARIS

SPINAL NERVES

• 31 PAIRS

• CERVICAL

• THORACIC

• LUMBAR

• SACRAL

• COCCYGEAL

CAUDA EQUINA

CERVICAL ENLARGEMENT

• INFERIOR CERVICAL REGION

• GIVES RISE TO SPINAL NERVES THAT SERVE UPPER LIMBS

LUMBAR ENLARGEMENT

INFERIOR THORACIC

SUPERIOR LUMBAR REGIONS

GIVES RISE TO SPINAL NERVES THAT SUPPLY LOWER LIMBS

SPINAL CORD IN CROSS-SECTION

• ANTERIOR MEDIAN FISSURE

• POSTERIOR MEDIAN SULCUS

MENINGES OF THE SPINAL CORD

• DURA MATER

• ARACHNOID MATER

• PIA MATER

• DENTICULATE LIGAMENTS

SPINAL CORD COMPOSITION

• WHITE MATTER

• GRAY MATTER

GRAY MATTER OF THE SPINAL CORD

• GRAY COMMISSURE

• CENTRAL CANAL

• DORSAL/POSTERIOR HORNS

• VENTRAL/ANTERIOR HORNS

ROOTS OF SPINAL NERVES

• DORSAL

• VENTRAL

DORSAL ROOTS

• ENTER SPINAL CORD AT TIPS OF POSTERIOR HORN

DORSAL ROOT GANGLIA

• SPINAL GANGLIA

VENTRAL ROOTS

• LEAVE SPINAL CORD AT TIPS OF ANTERIOR HORN

• MOTOR

SPINAL NERVE

• FORMED BY FUSION OF DORSAL AND VENTRAL ROOTS

WHITE MATTER

• COMPLETELY SURROUNDS THE GRAY MATTER

DIRECTION OF TRAVEL

• UP THE SPINAL CORD TO HIGHER LEVELS OR THE BRAIN

• DOWN THE SPINAL CORD FROM BRAIN OR HIGHER LEVELS

• ACROSS THE CORD, FROM ONE SIDE TO THE OTHER

AREAS OF THE WHITE MATTER

• POSTERIOR FUNICULUS

• LATERAL FUNICULUS

• ANTERIOR FUNICULUS

TRACTS OR FASCICULI

• ASCENDING-SENSORY

• DESCENDING-MOTOR

ASCENDING TRACTS

• SENSORY

TYPES OF NEURONS

• FIRST ORDER

• SECOND ORDER

• THIRD ORDER

FIRST ORDER NEURON

• PERIPHERAL PORTION OF ITS NERVE FIBER IN SPINAL CORD

• CELL BODY IN DORSAL ROOT GANGLION

SECOND ORDER NEURON

• CELL BODY LOCATED IN SPINAL CORD OR MEDULLA

• CONNECTS FIRST ORDER WITH CELL BODY OF THIRD ORDER

THIRD ORDER NEURON

• CELL BODY LOCATED IN THE THALAMUS

• CONNECTS TO CEREBRAL CORTEX

DECUSSATION OF SENSORY INPUT

• CROSS AT LEVEL OF ENTRY

• CROSS A FEW SEGMENTS ABOVE

• CROSS IN THE MEDULLA

MAJOR ASCENDING TRACTS

• FASCICULUS GRACILIS

• FASCICULUS CUNEATUS

• SPINOTHALAMIC TRACTS

• SPINOCEREBELLAR TRACTS

FASCICULUS CUNEATUS

• LATERAL TO FASCICULUS GRACILIS

• UPPER LIMBS, TRUNK AND NECK

• PROPRIOCEPTION

• FINE TOUCH LOCATION

• TERMINATES IN NUCLEUS CUNEATUS

FASCICULUS GRACILUS

• MEDIAL TO FASCICULUS CUNEATUS

• LOWER LIMBS

• PROPRIOCEPTION

• FINE TOUCH LOCATION

• TERMINATES IN NUCLEUS GRACILIS

MEDIAL LEMNISCUS

SPINOTHALAMIC TRACTS

• SYNAPSE IN THALAMUS

• LATERAL SPINOTHALAMIC

• ANTERIOR SPINOTHALAMIC

LATERAL SPINOTHALAMIC TRACTS

• PAIN • TEMPERATURE

ANTERIOR SPINOTHALAMIC TRACTS

• TOUCH

• PRESSURE

SPINOCEREBELLAR TRACTS

• POSTERIOR CEREBELLAR TRACTS

• ANTERIOR SPINOCEREBELLAR TRACTS

• PROPRIOCEPTION• SYNAPSE IN

CEREBELLUM

DESCENDING TRACTS

• MOTOR

• PYRAMIDAL TRACTS

• EXTRAPYRAMIDAL TRACTS

PYRAMIDAL TRACTS

• CORTICOSPINAL TRACTS

• UPPER MOTOR NEURONS

• LOWER MOTOR NEURONS

• LATERAL CORTICOSPINAL TRACTS

• ANTERIOR CORTICOSPINAL TRACTS

EXTRAPYRAMIDAL TRACTS

• RUBROSPINAL TRACTS

• VESTIBULOSPINAL TRACTS

• TECTOSPINAL TRACTS

• OLIVOSPINAL TRACTS

• FUNCTIONS OVERLAP

• MODIFY CONTRACTIONS DEALING WITH POSTURE AND BALANCE

RUBROSPINAL TRACT

VESTIBULOSPINAL TRACT

TECTOSPINAL TRACT

OLIVOSPINAL TRACT

SPINAL REFLEX ARC

COMPONENTS OF A SPINAL REFLEX ARC

• RECEPTOR• SENSORY (AFFERENT) NEURON• INTEGRATING CENTER• MOTOR (EFFERENT) NEURON• EFFECTOR

MONOSYNAPTIC VS POLYSNAPTIC

STRETCH REFLEX

• PATELLAR REFLEX• RECIPROCAL

INHIBITION• RECIPROCAL

INNERVATION

PATELLAR REFLEX

TENDON REFLEX

NEURON POOLS

SPINAL DYSFUNCTIONS

• PARALYSIS

• LESIONS OF THE SPINAL CORD

• TABES DORSALIS

• POLIOMYELITIS

• SYRINGOMYELIA

• MULTIPLE SCLEROSIS

PARALYSIS

• MONPELEGIA

• DIPLEGIA

• PARAPLEGIA

• HEMIPLEGIA

• QUADREPLEGIA

COMPLETE TRANSECTION

• CORD IS SEVERED COMPLETELY

• ALL SENS

• ORY AND MOTOR FUNCTION BELOW IS LOST

• EXTENT OF PARALYSIS DEPENDS ON LEVEL WHERE TRANSECTION OCCURS

HEMISECTION

• PARTIAL TRANSECTION– ON ONE SIDE OR OTHER

FLACCID VS SPASTIC PARALYSIS

• FLACCID

• NO MOVEMENT

• SPASTIC

• EXAGGERATED, UNCONTROLLED MOVEMENTS

EFFECTS OF LESIONS IN THE SPINAL CORD

• DAMAGE IS LOCATED BY IDENTIFYING COMBINATIONS OF LOSS OF FUNCTION

POLIOMYELITIS

• VIRAL DISEASE• DESTROYS MOTOR NERVE CELL BODIES

IN ANTERIOR HORNS• ESPECIALLY IN CERVICAL AND LUMBAR

ENLARGMENTS• CAN LEAD TO RESPIRATORY OR HEART

FAILURE IF VIRUS INVADES NERVE CELLS IN MEDULLARY CENTERS

TABES DORSALIS

• SEQUELAE OF SYPHILIS

• POSTERIOR FUNICULI AND DORSAL ROOTS DEGENERATE

• ATAXIA

SYRINGOMYELIA

• SMALL FLUD FILLED CYSTS FORM IN GRAY MATTER OF SPINAL CORD, BRAIN STEM

• EPENDYMAL CELLS IN CENTRAL CANAL PROLIFERATE

• PRODUCES SENSORY DYSFUNCTIONS

• MOTOR WEAKNESS

• MUSCLE ATROPHY

MULLTIPLE SCLEROSIS

• CHRONIC DESTRUCTION OF MYELIN SHEATHS

• PLAQUES INTERFER WITH NORMAL NERVE TRANSMISSION

• AUTOIMMUNE DISORDER• VIRUS MAY TRIGGER• SYMPTOMS VARY DEPENDING ON

WHERE DAMAGE OCCURS

ENCEPHALITIS VS MYELITIS

MENINGITIS

• INFLAMMATION OF MENINGES

• CAUSES MAYBE FUNGAL, BACTERIAL AND VIRAL