Dendrite refers to “trees“in Greek, so that these are the small branched extension of the cell nerve cell. Axon refers to the “axis“in Greek, so axon is the long, thin protrusion of the neuron or nerve cell.
Secondly, the dendrite receives messages or information or electrochemical impulses from the external environment or from other neurons, thus functioning as input to the neuron. The function of the axon is send messages or any information or electrochemical impulses to the external environment or to other neurons. They are then the output for the neuron.
Neurons or nerve cells or neurons are the most basic and essential part of the nervous system and of the brain. These cells are specialised in sending and receiving motor commands and sensory inputs, respectively, to and from the external environment. In short, they transmit and transform electrical signals for every action our body performs.
On top of that, nerve cells are responsible for our thought process, so they define or represent how we think, how we react and take actions at each and every step.
Likewise, a tree, neuron or nerve cell has three main parts: an axon, dendrites and a cell body or somawhich we can call the roots, branches and trunk of a tree. In this article, we will look at the difference between dendrites and axons, and we will also look at their description.
Comparative graph of dendrites and axons
| BASIS FOR COMPARISON | DENDRITA | AXON |
|---|---|---|
| Direction Sense | A dendrite is an expansion of a nerve cell, and these are short, numerous branching developments present in a cell. | The axon is the long, slender projection of a neuron or nerve cell that are individual cells. |
| Other characteristics | There are many dendrites in a nerve cell. | There is only one axon per neuron or nerve cell. |
| The dendrites are very short. | The axon is very long. | |
| They have branches everywhere, like the branches of a tree. | The axons are branched on the end side. | |
| Dendrites have their origin in the nerve cell. | The axon originates from the axon hillock, which is the conical projection. | |
| 1. There are numerous spines on the dendrites which provide the surface for other nerve cells to make synapses or form a neural junction (the electrical nerve transmission platform between two neurons). 2. These synapses receive information from an external environment or from other cells, so the dendrites become postsynaptic. |
Axons are presynaptic because at the end they have terminal buttons or synaptic boutons where the synapse is located. | |
| The junction between the dendrites that synapse on the axons is called axodendritic. | The synaptic junctions of axons contain neurotransmitters that contain numerous vesicles. They also have channels such as ‘Ca2+ channels’ in their membrane. | |
| The junction between dendrites that synapse with other dendrites is known as dendrodendritic. | The synaptic cleft (space between another cell and the terminal boutons) is about 20 nm thick. | |
| The dendrites carry Nissl granules. | Axons do not have Nissl granules, but neurofibrils do. | |
| Ribosomes are present in the dendrites, which have tapered ends so that their diameter decreases. | Axons have no ribosomes and are uniform in diameter. | |
| Functions | Receives messages or signals or nerve impulses from the external environment or from other nerve cells. | Axon sends or transfers nerve signals or impulses to the external environment or to other neurons. |
Definition of dendrite
The growth or extended part of a nerve cell or neuron is called a dendrite. dendrite. As stated above, dendrites spread out or branch like a tree, and there are many dendrites in a nerve cell. These branches help and support the reception of signals from the other synapses.
The main function of the dendrite is to receive the nerve impulse or signals that arrive to form other synapses and send them back to the cell body. Signals from dendrites or electrochemical messages take the form of neurotransmitters, sent by other neurons through the receptor a special receptor on the outside of dendrites.
Dendrites are not myelinated, due to the short projections and tapered ends. The dendrite was discovered by the ‘ Wilhelm His (Mall 1905) He was a Swiss anatomist in 1889.
Definition of axon
The nerve fibre or axon is the fundamental part of a nerve cell (neuron) that carries signals or information in the form of nerve impulses from the cell body to the outside environment. As mentioned, the nerve cell has only one axon, which projects long and thin and connects it to other muscle cells, glandular cells and other neurons.
The length of axons is quite long, and some can be as long as the spinal cord up to the finger of the toe. In vertebrates, the axons are enclosed within an myelin sheath and result in increased or rapid impulse transmission; like some large axons, they transmit impulses at a speed of 90 metres (300 feet) per second. The presence of this myelin (substance fat) is responsible for the white matter of the brain.
The axon is the long wire that stretches from the nerve cell or neuron in the brain to other parts of the body, and these are even thinner than hair and work to transmit electrical impulses from the nerve cell to other neurons.
Axons have side branches known as collateral axons, which help send the same information to other neurons. These collaterals extend in the same way as the roots of the tree, which has subroots that split off like terminal branches; and each of their tips has a synaptic terminal.
The point of communication of neurons is the synapse, i.e. the junction between the axon terminals and the cell bodies or dendrites of the other cell. At this point, electrical signals coming through the axons are converted into chemical signals, with the help of a neurotransmitter, and then converted back into electrical signals and transferred to other neurons.
Key differences between dendrite and axon
The following points are essential to differentiate the two most important parts of the nerve cell, which are the dendrite and the axon:
- According to the ‘Greek’ word, ‘ dendrite refers to a ‘tree’ and, therefore, the dendrite is an expansion of a nerve cell, these are short, numerous branching developments present in a cell. On the other hand, ‘ axon ‘ refers to ‘axon’ in ‘Greek’, so axon is the projection on the long, slender form of a neuron or nerve cell, which are individual cells.
- There is many dendrites in a nerve cell and they are short; whereas there are only an axon per neuron or nerve cell, but its length is long.
- The branches of the dendrites extend everywhere, like the branches of a tree, while the axons branch off at the end known as collateral axons.
- Dendrites originate from the nerve cell; however, the axon originates from the axon hillock, which is the conical projection.
- There are numerous spines on the dendrites that provide the surface for other nerve cells to make synapses or form a neural junction (the electrical nerve transmission platform between two neurons). These synapses receive information to form an external environment or other cells, so the dendrites become postsynaptic. Axons, on the other hand, are presynaptic, because at the end they have terminal buttons or synaptic boutons where the synapse is located.
- The junction between the dendrites that synapse with the axons is called the axodendriticThe synaptic nodes of axons contain neurotransmitters, which contain numerous vesicles. They also have channels such as ‘Ca2+ channels’ in their membrane.
- The junction between dendrites that synapse with other dendrites is known as a dendrodendriticThe synaptic cleft (space between another cell and the terminal boutons) is about 20 nm thick.
- Dendrites carry Nissl granules y are not myelinatedalthough the axons do not have Nissl granules, they are myelinated.
- The functions of the dendrite are to receive messages, signals or nerve impulses from the external environment or other nerve cells, while the axon sends or transfers signals or nerve impulses to the external environment or to other neurons.
Similarities
- Axons and dendrites are the extension or growth of the nerve cell or neuron, but they play a fundamental role for the nerve cell.
- Both are useful in the transmission of nerve impulses or signals.
- Both have neurofibrils and are branched in structure.
Conclusion
So, from the above content, we can say that the dendrite is the afferent, while the axon is the efferent component of nerve impulses and works to send and receive electrical impulses. As we know, dendrites have a shorter length than axons, although axons are myelinated and dendrites are not, this improves the speed of sending the signal to other cells.