Our brain has a network of neurons to communicate with other cells and carry out various complex tasks of our body. Axons and dendrites are both parts of a neuron. A neuron is a basic specialized brain cell which is responsible for receiving and transmitting information from cells through electrical signals to various parts of our body. Both axons and dendrites help a neuron in transmitting this information from a cell to another.
Axons vs Dendrites
The main difference between dendrites and axon is that dendrites receive information as electrical signals with the help of small receptors present on their surface. This signal passes through the cell body into the axon.
Axons pass the information in the form of an electrical signal from the cell body towards its terminal. There are small branch-like projections at its terminal which establish a connection with other dendrites and pass the electrical signal to communicate with other neurons.
Comparison Table Between Axons and Dendrites
| Parameters of Comparison | Axons | Dendrites |
| Shape | Elongated fibre like projection. | A small branch like projection. |
| Length | It is the longest part of a neuron. | A dendrite is comparatively shorter. |
| Structure | It contains neurofibrils but lacks Nissl’s granules and forms a synaptic knot at the end. | It contains both neuro- fibrils and Nissl’s granules. but does not form a synaptic knot at the end. |
| Number (in a single neuron) | A neuron has just one axon ( sometimes arising directly from a dendrite, but generally originated from the soma or cell body). | A neuron has many dendrites originated from the cell body. |
| Function | It transmits the electrical signal from the soma or cell body to the dendrite of another neuron. | Dendrite receives the electric signal from axon through the synaptic knot and brings it to the cell body of the neuron. |
What is Axon?
An axon passes the information from the cell body (Soma) to the dendrite of another neuron in the form of an electrical impulse through the synaptic gap. These axons can be a few millimetres to more than one metre long. The axon of our motor neurons can be stretched from our spine to the toe.
An axon is the long projection of a neuron with branch-like structures at the end. It is connected with the cell body of the neuron (Soma) through axon hillock. It consists of a microtubule and some microfilaments. Scientists believe that these structures help in transporting nutrients and electrical impulse from the cell body to the axon. It is surrounded by a Myelin sheath (a kind of fatty material) in the form of Schwann cells. Myelin sheath provides support to the neuron and works as an insulator and conductor. There is a periodic gap after each Schwann cell throughout the axon. These gaps are known as the nodes of Ranvier where the electrical signal or impulse get recharged before entering into the next Schwann cell.
At its end, the neuron splits into branch-like structures called telodendron whose end part is known as an axon terminal. These terminals form a synaptic knot in which they discharge the electrical signals in the form of neurotransmitters to be received by a dendrite of another neuron cell.
A neuron generally has one axon originating from the cell body but sometimes axons arise directly from the dendrite.
What is Dendrite?
A dendrite is a small branch-like projection of a neuron. Dendrites have small spine-like structures on its surface on which the axon of another neuron get attached through the synaptic gap. The dendritic spines increase the surface area to connect with another neurons.
This synaptic gap is formed between the terminal of an axon and the surface of a dendrite. The axon passes the information towards its terminal where dendrite receives the information in this synaptic gap through small receptors present on the surface of its spine.
Dendrites contain structures like ribosomes, smooth endoplasmic reticulum, Golgi apparatus and cytoskeletal structures.
There may be no dendrites at all but generally, a neuron has many dendrites. A large number of dendrites with a branch-like structure increases the surface area of a neuron to connect with other neurons.
Main Differences Between Axon and Dendrite
- Function: axon is the transmitter of the information and dendrite is the receiver of the information.
- Appearance: An axon is a long thread-like structure has small branches at it’s terminal but a dendrite looks like a branch of a tree.
- A dendrite is a continuous structure while an axon has small gaps between its outer Schwann cells.
- An axon forms a synaptic knot at the end but a dendrite does not.
- A dendrite has spines on its surface to get attached to axons of other neurons but axon does not.
- Dendrites possess receptors but axons do not.
- A neuron has only one axon but several dendrites. However, a neuron does not have any dendrite in some cases.
- An axon may be originated directly from an axon but a dendrite does not arise from an axon.
- A dendrite has several receptors on its surface to receive the electrical impulse in the form of some kind of chemical which again turned into an electrical signal or impulse before sending it to the cell body (soma), but axons lack such receptors.
Conclusion
A neuron plays a very important role in establishing communication with various cells especially in the organism with complex structures, like human beings.
Both axons and dendrites are parts of neurons and these neurons are responsible for communicating with different kind of cells of our body.
Injuries in either axons or dendrites affect this ability and function of neurons to establish communication with other cells.
Disruption in this cellular communication can cause diseases like Parkinson’s disease, Huntington’s disease, Alzheimer’s disease and spinal injuries etc.
Neurons grow when we are young but they naturally die as we grow older. We need to take care of our brain by taking good diet and following a good routine.
References
- https://ieeexplore.ieee.org/abstract/document/6268815/?casa_token=s544zcKUO2YAAAAA:rN41VzA3auSOWE4MX7T3671hagvt2NWBl7fayF0Imz7PJq7WUuBCwDrEy0HE8X0MDZcqaJyMm7Y
- https://www.sciencedirect.com/science/article/pii/S095943889900046X