Question

Explain the process of conduction of a nerve impulse along a nerve fibre.

Answer 1

Neurons seem to be in a resting state where they do not execute any impulses. In this case, the membrane is just not permeable towards sodium ions and proteins present in the axoplasm that are negatively charged, and is much more permeable towards potassium ions.

Complete answer:
First we should know about neurons to answer this question. A living organism consists of multiple cell types, which allow them to regulate and communicate with their environment. Coordination is the successful product of two processes in the animal body, i.e. the nervous system as well as the endocrine systems. Neurons are the human and animal structural and functional components of the nervous system. Neurons' ability to create and execute impulses makes them unique. In the production of impulses, the various forms of ion channels present on the neural membranes support.

Myelinated and unmyelinated are two kinds of nerve fibres. The action potential is carried out in a hopping fashion from node to node in myelinated nerve fibre. It is because the myelinated nerve fibre has a myelin sheath layer on it. The sheath of myelin is impervious to ions. As a consequence, nerve fibre ion exchange and depolarization are not necessary over the whole length of the nerve fibre. It happens only at some stage, known as Ranvier nodes, while the ion exchange and depolarization of nerve fibre occurs over the whole length of the nerve fibre of non-myelinated nerve fibres. The depolarized region becomes repolarized due to this ionic exchange, and the next polarised area gets depolarized.

Note: Active ion movement occurs via the sodium-potassium pump through the membrane, where 2 potassium ions enter the cell while 3 sodium ions are transferred outward. Consequently, the inner side is charged negatively and the external layer of the membrane is charged positively. The cell is in a polarized state. The electrical potential difference, formed by the resting plasma membrane, is the resting potential.