Question

Polio is caused by a virus that infects somatic motor neurons and destroys them. a) From this information, would you expect a polio victim to lose sensation, motor control, other organ function, and/or cognitive function? Explain.

Answer 1

Answer

→ to lose sensation,

→ motor control

Explanation:

Anatomically the spinal cord is made up of two roots, the Dorsal roots or the posterior roots where motor or efferent neuron leaves the spinal cord to innervate the skeletal muscles, trunks  and the Ventral root or anterior roots where the afferent or sensory neuron  convey input  signals to the  spinal cord from the the receptors.

Polio virus usually destroyed  the nucleus of motor neurons, in the ventral roots of the spinal cord. its inflamed these  cells, leading to death, The death  leads to consequent degeneration  at the site of inflammation, and progressive spread  of this to other segments of the nerve fibre. This is called Wallerian Degeneration.  Thus mechanisms of  generation and transmission of action potential  in these motor neuron is inhibited.

Consequently, motor output signals by the efferent neuron leaving through the dorsal roots is disrupted, and blocked . Thus effectors-muscles of limbs,trunks, are no longer innervated and stimulated, by efferent responses from the spinal cord and  the brain, thus  leading to loss of  sensation and motor control.

With muscles redundancy, from  lack of stimulation, muscles cells  begin to waste away(muscle atrophy), and not able to control by the victim.This is paralysis.