Devic's syndrome is a condition involving the demyelination of the optic nerve and the spinal cord. Which of the following neuronal effects is NOT a direct result of Devic's syndrome? A.Decreased protection of the neuronB.Decreased speed of impulse propagationC.Decreased strength of the action potentialD.Decreased electrical insulation
Question
Devic's syndrome is a condition involving the demyelination of the optic nerve and the spinal cord. Which of the following neuronal effects is NOT a direct result of Devic's syndrome? A.Decreased protection of the neuronB.Decreased speed of impulse propagationC.Decreased strength of the action potentialD.Decreased electrical insulation
Solution
The answer is C. Decreased strength of the action potential.
Devic's syndrome, also known as Neuromyelitis Optica, primarily affects the optic nerve and the spinal cord by causing demyelination, or the loss of the myelin sheath. The myelin sheath is a protective covering for neurons that also aids in the speed of impulse propagation, so A and B are direct results of Devic's syndrome.
The myelin sheath also provides electrical insulation for the neuron, so D is also a direct result of Devic's syndrome.
However, the strength of the action potential, or the electrical signal that travels down the neuron, is not directly affected by the myelin sheath and therefore not directly affected by Devic's syndrome. The strength of the action potential is more so determined by the ion channels and the neuron's ability to generate an electrical signal, not the presence of the myelin sheath.
Similar Questions
Which of the following Demyelinating disorders affects motor function only. aMultiple Sclerosis bAmyotrophic Lateral Sclerosis cGuillian-Barre Syndrome dParkinson's Disease
Axons of which cells in the retina form the optic nerve?a) Amacrine cellsb) Photoreceptor cellsc) Horizontal cellsd) Ganglion cellse) Bipolar cells
Which of the following cranial nerve assesses Nystagmus. aCN III (Oculomotor) bCN IV (Trochlear) cCN V (Trigeminal) dNone of the above
In Guillain-Barre Syndrome, the Immune System Attacks and Degrades the Myelin Sheath of PNS Axons. Predict the Effect This Will Have on Nerve Impulse and Motor Function.In Guillain-Barre syndrome, the immune system attacks and degrades the myelin sheath of PNS axons. Predict the effect this will have on nerve impulse and motor function.Multiple ChoiceLost insulation from myelin will cause neurons of the PNS to be hyper-excitable and muscular spasms will result.The brain will slowly degrade and various brain functions will be lost, including motor functions.Lost insulation from myelin will cause neurons of the PNS to lose saltatory conduction, resulting in poor muscle function.Motor signals will not be sent from the brain down the efferent pathway because the brain cannot generate them.
Which cranial nerve(s) are responsible for the pupillary light reflex (direct/consensual)?Group of answer choicesCN III, IV, VICN IICN II and III
Upgrade your grade with Knowee
Get personalized homework help. Review tough concepts in more detail, or go deeper into your topic by exploring other relevant questions.