Question 7
Describe in brief the structure of the axon of the nerve cell.
Answer
The axon is a long, cylindrical fibre that extends from the cell body of a nerve cell (neuron) and transmits electrical impulses and signals away from the cell body towards other neurons or target cells. The structure of the axon includes:
- Axon hillock: A cone-shaped region at the base of the axon that connects to the cell body and initiates nerve impulses.
- Myelin sheath: A layer of fatty insulation that covers the axon and helps to increase the speed of nerve impulses. The myelin sheath is made up of specialized cells called Schwann cells in the peripheral nervous system and oligodendrocytes in the central nervous system.
- Nodes of Ranvier: Gaps in the myelin sheath along the length of the axon that allow for the rapid conduction of nerve impulses.
- Axon terminals: Specialized structures at the end of the axon that transmit signals across the synapse to other neurons or target cells. The axon terminals contain vesicles filled with neurotransmitters that are released in response to a nerve impulse, allowing for communication between neurons.
