Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Handout 10 -- Spinal Tracts
Document related concepts
Transcript
WHICH ASCENDING TRACTS DO I NEED TO KNOW AND WHAT DO I NEED TO KNOW ABOUT THEM? name of tract location in spinal cord origin of 1st order neuron origin of 2nd order neuron site of decussation fasciculus gracilis dorsal column dorsal root ganglia nucleus gracilis in medulla medulla, to form the medial lemniscus fasciculus cuneatus dorsal column dorsal root ganglia nucleus cuneatus in medulla medulla, to form the medial lemniscus lateral spinothalamic lateral column dorsal root ganglia dorsal horn of incoming segment gray commissure of incoming segment ventral spinothalamic ventral column dorsal root ganglia dorsal horn of incoming segment gray commissure of incoming segment dorsal and ventral spinocerebellar dorsal and ventral columns dorsal root ganglia dorsal horn of incoming segment 2nd order neuron terminates in cerebellum origin and termination of 3rd order neuron thalamus to primary somatosensory cortex thalamus to primary somatosensory cortex thalamus to primary somatosensory cortex thalamus to primary somatosensory cortex no thirdorder neuron proprioception -- nonvisual sense of the position and movements of the body kinesthesia -- sense of muscular movement stereognosis -- understanding size, shape, and texture of an object by feeling it functions conscious or unconscious from T6 down – proprioception, deep and discriminative touch, kinesthesia, weight discrimination, stereognosis, visceral pain, vibration conscious conscious from T6 up – same as above pain, hot and cold sensations conscious itch, tickle, pressure, vibrations, crude touch sensation conscious proprioception unconscious WHICH DESCENDING TRACTS DO I NEED TO KNOW AND WHAT DO I NEED TO KNOW ABOUT THEM? name of tract lateral corticospinal ventral corticospinal pyramidal or extrapyramidal pyramidal location in spinal cord lateral column origin of upper motor neuron primary motor cortex site of decussation medulla pyramidal ventral column primary motor cortex corticobulbar pyramidal cerebral peduncles of midbrain primary motor cortex tectospinal extrapyramidal ventral column superior colliculus gray commissure of outgoing segment some fibers decussate, others do not varies vestibulospinal extrapyramidal ventral column lateral and medial reticulospinal extrapyramidal ventral column vestibular nucleus of brainstem via the inner ear reticular formation of brainstem none none origin of lower motor neuron ventral horn of outgoing segment ventral horn of outgoing segment functions control of voluntary skeletal muscle activity via the spinal nerves (neck, trunk, limbs) control of voluntary skeletal muscle activity via the spinal nerves (neck, upper limb) nuclei of cranial control of voluntary skeletal muscle nerves with activity via the cranial nerves motor (facial expression, chewing functions, ventral horn of reflexive head and eye movements in outgoing response to visual and auditory segment and stimuli appropriate cranial nerves ventral horn of reflexive control of muscle tone for outgoing maintaining balance and posture in segment response to head movements ventral horn of outgoing segment reflexive control of muscle tone for maintaining balance and posture, modulation of flexor and extensor reflexes
