Why the nerve cell is so long?
Why the nerve cell is so long?
The longest efferent neuron directs muscular activity in the foot. Its cell body is in the basal ganglia near the brain, and its axon runs through the spinal column and down the leg to the foot.
The longest afferent neuron in the human body runs from the foot to the top of the spinal column. Its cell body is in a ganglia near the end of the end of the spinal chord. It has a long axon that enters the spinal column and connects upward, and it has a long dendrite (or dendrite-like fiber) that runs downward to the foot.
There is time lost in every synapse as the electrical impulse in the axon is converted into a slower chemical impulse across the synapse. So the number of synapses is minimized when time is critical, as in sensory neurons involved in proprioception supporting critical physical activities such as walking and running.
The longest efferent neuron directs muscular activity in the foot. Its cell body is in the basal ganglia near the brain, and its axon runs through the spinal column and down the leg to the foot.
The longest afferent neuron in the human body runs from the foot to the top of the spinal column. Its cell body is in a ganglia near the end of the end of the spinal chord. It has a long axon that enters the spinal column and connects upward, and it has a long dendrite (or dendrite-like fiber) that runs downward to the foot.
There is time lost in every synapse as the electrical impulse in the axon is converted into a slower chemical impulse across the synapse. So the number of synapses is minimized when time is critical, as in sensory neurons involved in proprioception supporting critical physical activities such as walking and running.
