Neuron
Neuron – The Longest Cell in the Human
A cell in the lumbar posterior root ganglion has a running length greater than the height of the individual. The ratio of the total length to the diameter of the cell body is in terms of at least a million. Needless to say such a cell in a whale would be 100 to 150 feet long. The moot question is of nourishing such a cell. It is suggested here that the autorhythmic retinal cochlea and stretch receptors start a cycle that begins in the peripheral senses to converge onto the CNS and then to diverge out to the muscles. This assures a stimulatory kick delivered at regular intervals to the very tall neurons and the moderately tall muscle cells (a single fibre in a whale sartorius is 800 cm’s). This explains why sensory denervation occasions the most profound muscular paralysis. It also explains how on the loss of stimulatory kick neurons and muscle cells whither away.
Seth G.S. Medical College, Parel, Mumbai
