Question

Locate and discuss the differences between the dorsal white column (fasciculatus gracilis and fasciculatus cuneatus) and spinothalamic tract afferent pathways and pyramidal and extrapyramidal motor pathways. Discuss why there are two separate afferent and efferent pathways rather than just one afferent and one efferent pathway.

Answer 1

The dorsal white column in the spinal cord is a ascending tract has a two nucleus known as fasciculatus gracilis, fasciculatus cuneatus. The fasciculus gracilis is also named as tract of goll that carry the lower body touch sensation and the fasciculus cuneatus is also named as tract of burdach that carry upper body touch sensation.

The spinothalamic tract carries the pain and crude touch sensation via the lateral spinothalamic tract and ventral spinothalamic tract.

The difference between the spinothalamic tract and dorsal white column tract is the dorsal white column tract do not cross the midline of the spinal cord but the spinothalamic tract cross the midline of spinal cord. There is no reticular formation in the midbrain part of brain stem of dorsal white column but there is a reticular formation in the spinothalamic tract in the midbrain part of brain stem. The dorsal white column do not relay on spinal cord but the spinothalamic tract relay in the spinal cord.

Difference of pyramidal and extrapyramidal tract are :The pyramidal tract of motor system has lateral, anterior corticospinal tract, and this tract originates from cerebrum-the cortex and it terminates at the spinal cord anterior horn and from there the fibres reaches the muscle. This pyramidal tract crosses the pyramids in the medulla and it control the voluntary movement. The extrapyramidal tract do not cross the pyramids of medulla and it controls the muscle tone, posture control. This system has tectospinal tract, rubrospinal tract, reticulospinal tract, vestibulospinal tract and olivospinal tract.

The afferent and efferent pathways are different and are not connected together because the neural pathway carries only the one sensation and the afferent pathway relays from the afferent organ receptor to brain but the efferent pathway relays from brain to the efferent organ. So both the origin and termination differs so it cant be connected together.