Question

Choose the correct statement(s) about impulse transmission in a neuron:

• A. Voltage gated ion channels present at regular intervals in unmyelinated neuron ensure impulse transmission.
• B. Myelinated neurons have myelin allows the movement of ions at a fast pace resulting in faster signal transmission.
• C. Nodes of Ranvier are breaks in myelin sheath and voltage gated channels are clustered here.

Answer 1

Answer: (A), (C)

The correct options are
A Voltage gated ion channels present at regular intervals in unmyelinated neuron ensure impulse transmission.
C Nodes of Ranvier are breaks in myelin sheath and voltage gated channels are clustered here.

Unmyelinated neuron lack insulation. So, voltage gated channels are present at regular intervals for the generation of action potential at regular intervals. In case of myelinated neurons, myelin sheath prevents the loss of ions as ions are insoluble in fats. Hence, myelin ensures that ions are prevented from passing through all leak and voltage gated channels. The change in polarisation is transmitted as an electrical current directly through the cytoplasm of the myelinated axon. Since, the electrical current will be weakened after travelling some distance in the axon. Hence, Nodes of Ranvier has all the leakage and voltage gated ion channels clustered. It is basically the breaks in myelin sheath. This conduction method is known as saltatory conduction.