Neural Control And Coordination Ques 20
20. Which of the following statements is correct for ’nodes of Ranvier’ of nerve?
(a) Neurilemma is discontinuous
(b) Myelin sheath is discontinuous
(c) Both neurilemma and myelin sheath are discontinuous
(d) Covered by myelin sheath
Show Answer
Answer : b
Hints & Solutions
(b) Neurons are the chief functional units of the nervous system. An ordinary neuron has a soma or cyton and a long thread called axon which is enclosed in a multilayered myelin sheath, made by Schwann cells. The myelin sheath is interrupted at the spaces between schwann cells to form gaps. These gaps are called Nodes of Ranvier. These nodes and the myelin sheath create condition that speed up the nerve impulses.
BETA
