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In vertebrates, an axon, also known as a nerve fibre (or nerve fibre), is a long, slender projection of a nerve cell, or neuron, that transports electrical impulses known as action potentials away from the nerve cell body. Dendrites are a neuron’s (nerve cell) projections that receive signals (information) from other neurons. To carry information from one neuron to another, chemical signals and electric impulses, often known as electrochemical signals, are used .
Axon
An axon is a long process of a neuron (or nerve cell) that is involved in nerve impulse conduction away from the cell body. Axons, which can be over a foot long, are found in each nerve cell. Signals are sent from the branches at the end of a nerve cell’s axon to communicate with another nerve cell. The impulses are delivered to additional nerve cells or effector organs at the axon’s terminal end.
The bigger (myelinated) axons in the peripheral nervous system are wrapped by a myelin sheath made up of concentric layers of schwann cell plasma membrane. Oligodendrocytes (oligodendroglia) supply the schwann cell’s function in the central nervous system.
Function of axon
Axons assist in the transmission of information between neurons. They develop axon collaterals, which are side branches that allow them to relay messages to multiple neurons at once.
Dendrite
Dendrites are long structures that connect nerve cells (neurons). These take up a lot of space on a neuron’s surface. They receive a large number of messages from other neurons and have specialised proteins that receive, process, and send these signals to the cell body. Organelles in dendrites allow them to modify protein density in response to changes in neuronal input frequency. This permits neurons to retain normal activity, which helps to prevent neurological illnesses like epilepsy. Dendrites are therefore essential for appropriate neuronal function and play a key part in physiological processes including memory formation .
Function of dendrite
Dendrites have the ability to accept impulses from other neurons, process them, and transmit the information to the neuron’s soma.
Difference between axon and dendrite:
Axon | Dendrite |
The long thread-like portion of a nerve cell that carries nerve impulses away from the cell body is called an axon. | Dendrites are the small branched extensions of nerve cells that transport nerve impulses from synapses to the cell body. |
There is only one axon in a nerve cell. | The dendrites of a nerve cell are many. |
An axon arises from a conical projection called axon hillock. | Dendrites emerge from the nerve cell directly. |
Axons are quite lengthy (several metres). | Dendrites are very short strands of tissue (around 1.5 mm). |
The diameter of axons is constant. | Dendrites have tapering ends, so their diameter diminishes over time. |
The terminals of axons are branching. | All of the dendrites are branching. |
Synaptic knobs are formed by enlarging the terminals of the axon’s terminal branches. | At the tips of the dendrites’ branches, there are no synaptic knobs. |
Axon synaptic knobs contain vesicles containing neurotransmitters. | Neurotransmitter-containing vesicles do not exist in dendrites. |
Nissl’s granules are not seen in axons. | Nissl’s granules are found in dendrites. |
Axons can be myelinated or unmyelinated. | Dendrites are myelinated but not myelinated. |
Nerve impulses are carried away from the cell body via axons. | Nerve impulses are carried by dendrites to the cell body. |
The efferent component of a nerve impulse is made up of axons. | The afferent component of the nerve impulse is formed by dendrites. |
Similarities Between Axon and Dendrite
Both the axon and the dendrite are extensions of the cell body of a nerve cell.
Nerve impulses are transmitted by both the axon and the dendrite.
Both the axon and the dendrite are branching.
Neurofibrils can be found in both the axon and the dendrite.
Direction of Conduction in axon and dendrite
The axon emerges from the soma at the axon hillock, also known as the beginning segment. The plasma membrane creates nerve impulses in this region, and the axon carries these impulses away from the soma or dendrites to other neurons. The nerve impulse only has one direction of travel. Other neurons provide nerve impulses to the dendrites, which are then received by the dendrites. This impulse passes from the dendrite to the cell body before being transmitted to another neuron or receptor at the axon’s end .
Conclusion
A nerve cell’s axon and dendrite are the two forms of projections. Nerve impulses are transmitted by both axons and dendrites. Dendrites are shorter than axons. Axons have a consistent diameter, whereas dendrites have tapering ends. To speed up the transmission of nerve impulses, some axons are myelinated. Nerve impulses are sent away from the cell body by axons and towards the cell body by dendrites. As a result, the primary distinction between axon and dendrite is the direction in which nerve impulses are transmitted .
