Tracts Flashcards
(23 cards)
Tracts of the spinal cord
-definition
White matter connecting areas of the brain
Ascending tracts
-names (6)
- Gracile fasciculus
- Cuneate fasciculus
- Dorsal and ventral spinocerebellar tract
- Anterior and lateral spinothalamic tract
Descending tracts
-names (8)
- Ventral and lateral corticospinal tract
- Lateral and medial reticulospinal tract
- Tectospinal tract
- Lateral and medial vestibulospinal tract
- Rubrospinal
Ascending tracts
-characteristics
Neural pathway by which sensory info from the site of stimulus (outside CNS) to the cerebral cortex
-sensory
Descending tracts
-characteristics
Pathways by which motor signals are sent from the brain to the lower motor neurones
-motor
Tracts at the posterior funiculus (2)
Gracile and cuneate
-all ascending (sensory)
Tracts at the lateral funiculus (5)
- Lateral spinothalamic tract (S)
- Anterior and posterior spinocerebellar tract (S)
- Lateral corticospinal tract (M)
- Rubrospinal tract (M)
- Lateral reticulospinal (M)
Tracts at the anterior funiculus (5)
- Anterior spinothalamic tract (S)
- Anterior corticospinal tract (M)
- Medial reticulospinal tract (M)
- Lateral and medial vestibulospinal tract (M)
- Tectospinal tract (M)
Gracile and cuneate fasciculi
-function
Proprioceptive (position, sense and movement) and Exteroceptive (touch, pressure, vibration) information
Spinothalamic tract
-function
Anterior spinothalamic –> touch and pressure
Lateral spinothalamic –> pain and temperature
Spinocerebellar tract
-function
Proprioceptive (position, sense and movement) and Exteroceptive information (touch, pressure, vibration)
Vestibulospinal tracts
-function
Excites motor neurons of extensor muscles, inhibit motor neurons of flexor muscles
-involuntary things
Rubrospinal tracts
-function
Excites flexor muscles and inhibits extensor ones
Reticulospinal tracts
-function
Medial: posture, crude and stereotyped movements of the limb.
Lateral: control of pain perception
Corticospinal and cortico-nuclear tracts
-function
Resposible for voluntary movements
Gracile and cuneate fasciculi
-pathway
1st neurons –> spinal ganglion
2nd neurons –> nucleus gracile and cuneate (gracile lower spinal segments, cuneate upper thoracic and
cervical segments)
Medial lemniscus
3rd neurons –> ventral- post lateral nucleus (thalamus)
Post- central gyrus
Spinothalamic tracts
-pathway
1st neurons –> spinal ganglion
2nd neurons –> spinal cord
Fibers cross the spinal cord
Spinoreticular and spinotectal tracts
3rd neurons –> ventral post- lateral nucleus
Post- central gyrus
Spinocerebellar tracts
-pathway
1st neurons –> spinal ganglion
2nd neurons –> spinal cord
Posterior spinocerebellar –> passes through inferior cerebellar peduncle
Anterior spinocerebellar –> passes through superior cerebellar peduncle
Cuneo- cerebellar tract –> passes through inferior cerebellar peduncle
Corticospinal and cortico- nuclear tracts
-pathway
Precentral gyrus (primary motor area)
Crus cerebri (mid-brain)
Cortinuclear tract: nuclei of the cranial nerve, some fibers decussate, some not
Lateral corticospinal: pyramidal decussation
Anterior corticospinal: decussation in the spinal cord
Motor neurons of the anterior horn
Vestibulospinal tracts
-pathway
Vestibular nuclei
Lateral (ends ipsilaterally) and medial (contains both crossed and uncrossed fibers)
Rubrospinal tracts
-pathway
Red nucleus of the midbrain
Fibers cross
Tectospinal tracts
-pathway
Superior colliculus of the midbrain
Turning the neck to the contralateral side from the unilateral simulation of the superior colliculus
Reticulospinal tracts
-pathway
Reticular formation (medulla oblongata and pons)
Medial: ipsi- and contralateral fibers
Lateral: mostly crossed fibers
