The afferent or sensory nerve transfers the messages or signals from various organs to the spinal cord or brain. In contrast, efferent nerve or motor nerve transfer the messages or signals from the spinal cord or brain to multiple organs. That means their role is opposite, but they work in transferring signals between organs and spinal cord or brain.
When you rub your palms, do exercises, hit a ball, there is the involvement of afferent and efferent neurons that are responding to the stimulus, and so you are taking actions accordingly.
Interneurons are the third kind of neurons that act as the mediator between the two neurons, though being the part of the central nervous system; it creates a bridge between the afferent and efferent neurons and work coordinately to send the response against any stimulus.
Both the types of neurons are the part of the peripheral nervous system and consists of the dendrites, dendrons and the cell body; also these neurons play a vital role in responding to the sensory stimulus and transmits signals between organs and brain or spinal cord.
As we know, that our nervous system has two parts, the Central Nervous System (CNS) and the Peripheral Nervous System (PNS). The CNS or central nervous system involves the spinal cord and the brain; while PNS or peripheral nervous system includes the organs, glands, muscles and the whole body that are connected via the network of neurons. Thus, this network of neurons plays a vital role in performing every action of the body, whether it’s reading, writing, thinking, sensing, eating, etc.
The working of this nervous system is very simple like that of computer, it takes input and gives output, so input is any action on which our system provides reaction in the form of output.
Let’s take an example, that while walking on the road, your eyes saw that car might hit you, and so you jump or make the side of that way immediately. This was done because your eyes quickly send the signal to the brains that there can be something wrong and so your brain instantly send a message to the muscles of your leg to move out of the way.
Another example is, if you put your hand on top of the fire (burning candle or any flame), you will immediately remove it, this was again the action took by your brain on your senses.
Our body has various types of neurons, and they keep on working continuously, so the neurons that receive signals from the sensory organs (like skin, ears, tongue, eyes and nose) and then further transfer it to the central nervous system are the afferent neurons. The other neurons that work in sending the signals or messages from the central nervous system to the organs or limbs are the efferent neurons.
In this context, we will be going to discuss the about these two types of neurons (afferent and efferent), their ground of differentiation with a brief description.
Content: Afferent Vs Efferent Neurons
Comparison Chart
| Basis for Comparison | Afferent Neurons | Efferent Neurons |
|---|---|---|
| Meaning | The neurons that carry sensory impulses towards the central nervous system (CNS) is known as afferent neurons. | The neurons that carry motor impulses towards the central nervous system (CNS) is known as efferent neurons. |
| It contains | Long dendron and short axon and receptor. | Long axon and short and numerous dendrons. |
| Cell Body | The shape of the cell body is smooth and round. | The shape of the cell body is like a satellite. |
| Situated in | Afferent neurons are present outside the CNS. | Efferent neurons are present inside the CNS. |
| Main function | Afferent nerves transfer the messages or signals from various organs to the spinal cord or brain. | Efferent nerves transfer the messages or signals from the spinal cord or brain to various organs. |
| Present in | Ears, tongue, skin and nose. | Glands and muscles. |
Definition of Afferent Neurons
Afferent neurons, also known as sensory neurons. These neurons play a role in sensing the stimulus, and within the fraction of seconds, it sends information or signals to the central nervous system about the stimulus.
Sensory inputs include any smell, taste, feelings or emotions, which is carried from the receptor point to the spinal cord and then to the brain.
Definition of Efferent Neurons
Efferent neurons, also known as motor neurons. These types of neurons play a role in sending signals or information from the central nervous system to trigger the action.
It happens sequentially like after the sensory inputs are sent to the brain, it further conveys signals to the glands and muscles for the motor response through the efferent neurons.
Key Differences Between Afferent and Efferent Neurons
The following are the critical points to get the differences between the afferent and the efferent neurons:
- The neurons that carry sensory impulses towards the central nervous system (CNS) is known as afferent neurons. In contrast, such neurons that carry motor impulses towards the central nervous system (CNS) is known as efferent neurons. In short, we can say afferent neurons work or send signals felt by our sense organs to the brain or spinal cord and efferent neurons carry signals from the spinal cord or brain to the organs, glands or limbs that what kind of action to be taken on that senses.
- Afferent neurons have long dendron and short axon and receptor, while efferent neurons have a long axon and numerous and short dendrons.
- The shape of the cell body of the afferent neurons is smooth and round; on the other hand, the shape of the cell body of efferent neurons is like the satellite.
- Afferent neurons are present outside the CNS, but efferent neurons are present inside the CNS.
- The primary role of afferent nerves is to transfers the messages or signals from various organs to the spinal cord or brain, and efferent nerves transfer the messages or signals from spinal cord or brain to different organs and other parts of the body to take action accordingly.
- Afferent neurons are present in ears, tongue, skin and nose, while efferent neurons are present in glands and muscles.
Conclusion
Afferent and Efferent are similar sounding words and may create confusion to understand for the layman, as there are very fewer variations between the two terms. But these neurons are essential, in sensing and responding to any actions, like if we open a refrigerator and we found the basket of rotten vegetables, we will quickly remove it.
We can even sense any foul smell immediately, and our afferent neurons and efferent neurons instantly work on the respond. So we can sum up by saying that, ‘afferent = receive and efferent = act or react’.
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