Ascending tracks

 INTRODUCTION

Sensory tracks formed in the spinal cord by sensory fibres from receptors and ready higher centres in CNS are called Ascending tracks

a sensory input passes through the spinal cord, medulla and thalamus to reach CNS

spinal cord, medulla and thalamus are called relay stations

Ascending tracks carry various sensations through relay stations  to the CNS

they are present in the white matter of the spinal cord 

NEURAL COMPOSITION OF ASCENDING TRACKS

they have  a chain of successive neurons 

• First-order neuron
• cell bodies reside in the dorsal root ganglion 
• carries information from the receptor to the spinal cord 
• they don't relay sensation on face 
• they synapse with the second-order neuron
• Second-order neuron 
• nucleus present in the dorsal horn of the spinal cord
• they ascend and transmits the impulse to the thalamus or cerebellum
• Third-order neuron
• located in thalamus 
• conducts sensory impulse to the somatosensory cortex 
• it contains two types of tracks 
• specific ascending track 
• non- specific ascending track 

SENSORY TRACKS 

1. dorsal collum

    - track of goll (fasciculus gracillis) 

    - track of burdach (fasciculus cuneatus)

2. lateral collum 

      - lateral spinothalamic track

    - dorsal spinocerebellar track

    - ventral spinocerebellar track 

    - spinotectal track 

    - spino- olivary track 

    - spinovestibular track 

    - spinopontine track 

    - spinoreticular track 

3. ventral (anterior) collum

    - anterior spinothalamic track