What Is the Difference Between Sensory and Motor Neurons in Structure and Function
The study and practice of biology helps us to analyze the human body adequately. The nervous system is a critical part of our body that needs to be understood in order to lead a prosperous life. Neurons form the basic foundation for receiving sensory inputs, instructing the muscle through motor commands, and sending the signals back to the brain to initiate actions. Talking about the types of neurons on the basis of functions and structure, the central nervous system comprises two types of neurons- Sensory and Motor Neurons. We’ll be looking at the difference between sensory and motor neurons. The difference between sensory and motor neuron has been tabulated below:
Sensory Vs Motor Neurons
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We hope that it’s pretty much clear how sensory and motor neurons differ from each other. Now, we will be looking forward to our next section i.e. difference between sensory and motor neurons on the basis of their structure.
Structural Differences: Difference Between Sensory Neuron and Motor Neuron
Although the core function of the neurons differentiate between sensory neuron and motor neuron, both the neurons also differ in structure. Let’s look into the structural difference between the sensory neuron and motor neurons and what makes them different from each other.
Sensory Vs Motor Nerves: Difference Between Sensory Neuron and Motor Neuron
To differentiate between sensory neuron and motor neuron, we will be defining the structure of both the neurons one by one.
Sensory Nerves Vs Motor Nerves
Structure of Sensory Neurons:
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Sensory neurons conduct signals from sensory organs to the CNS. Sensory Neurons arise from the dorsal root ganglion, which are specialized clusters present at the dorsal roots of the spinal cord.
Sensory neurons lack distinct axons and dendrites.
Sensory neurons possess receptors.
The soma of the sensory neurons possesses a nucleus and other cell organelles.
A synaptic junction with second-order sensory neurons is formed as the central branch extends from soma to the posterior horn of the spinal cord.
These neurons are also known as pseudo unipolar neurons.
Structure of Motor Neurons
To understand the difference between sensory neuron and motor neuron in a better way, let's learn the structure of Motor neurons.
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Motor nerves transmit the signals from the CNS to the sensory organs and thus, help in initiating actions.
These neurons are located at the ventral root ganglion of the spinal cord.
Motor neurons consist of a long axon and multiple dendrons.
They lack receptors.
These neurons are also known as multipolar neurons.
These are the main differences between sensory and motor nerves.
We hope that the functional difference between sensory nerve and motor nerve is pretty much clear. Thus, we will be moving towards our next section that is to differentiate sensory nerves and motor nerves on the basis of the functions they perform.
Differentiate Between Sensory and Motor Neurons on the Basis of Functions
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Till now, we have just discussed the basic functions and how to differentiate between sensory neuron and motor neuron. But, the functions of sensory and motor neurons are vast. Let's compare and contrast sensory and motor neurons on the basis of the function they perform in the human body.
For the difference between sensory and motor neurons, let’s first look at the functions performed by sensory neurons.
Functions of Sensory Neurons
We will see the difference between sensory and motor nerves on the basis of function.
We know, sensory neurons transmit the signal from the sense organs to the CNS in the form of sensory signals. Let’s look at some of the most important functions performed by sensory neurons in the human body.
Controlling the Heartbeat and Blood Circulation
The sensory receptors in the blood vessels are responsible for registering blood pressure. Sensory neurons can be found in the aorta, carotid arteries, pulmonary artery, capillaries in the adrenal gland, and the tissues of the heart itself, from where the signals are sent to the medulla and thus, help in controlling BP and blood circulation.
Effects in Neuritis
Inflammation of sensory neurons results in the sensation of burning, tingling, or stabbing pain. These are even worse at night and are aggravated by temperature change.
Taste Buds
Taste receptor cells on our tongues form a group of 50 to 150. These cells respond to the chemicals present in the food and thus, form taste buds, which help us in differentiating among the food items of different tastes.
Fun Fact:
An average adult can have more than 8,000 taste buds!
Sensory neurons and motor neurons work in coordination which each helps in the functioning of our body. So, if you are able to taste something, it’s because of the harmonized working of both the neurons.
We hope that the difference between sensory nerve and motor nerve is now clear. The topic is pretty much simple and just needs a bit of understanding. The difference between sensory and motor nerves can be well understood with the table in the first section.
FAQs on Difference Between Sensory and Motor Neurons in the Nervous System
1. What is the difference between sensory and motor neurons?
The main difference between sensory neurons and motor neurons is that sensory neurons carry impulses from sense organs to the central nervous system, while motor neurons transmit impulses from the central nervous system to muscles or glands.
- Sensory neurons (afferent neurons): Carry signals from receptors to the brain or spinal cord.
- Motor neurons (efferent neurons): Carry signals from the brain or spinal cord to effectors like muscles and glands.
- This functional difference enables the body to detect stimuli and produce appropriate responses.
2. What are sensory neurons?
Sensory neurons are specialized nerve cells that transmit impulses from sensory receptors to the central nervous system (CNS).
- They detect stimuli such as light, heat, pain, touch, and sound.
- They are also called afferent neurons because they carry impulses toward the CNS.
- Their cell bodies are usually located in the dorsal root ganglion of the spinal cord.
3. What are motor neurons?
Motor neurons are nerve cells that transmit impulses from the central nervous system to muscles or glands to produce a response.
- They are also known as efferent neurons.
- They control voluntary actions like walking and involuntary actions like gland secretion.
- Their cell bodies are typically located in the spinal cord or brainstem.
4. How do sensory and motor neurons work together?
Sensory and motor neurons work together in a coordinated pathway to detect a stimulus and produce a response.
- Step 1: Sensory receptors detect a stimulus (e.g., heat).
- Step 2: Sensory neurons transmit the impulse to the CNS.
- Step 3: The CNS processes the information, often via interneurons.
- Step 4: Motor neurons carry the response signal to muscles or glands.
5. What is the function of sensory neurons?
The primary function of sensory neurons is to detect external or internal stimuli and transmit signals to the central nervous system.
- They respond to physical and chemical changes in the environment.
- They help in sensations such as vision, hearing, taste, smell, touch, and pain.
- They initiate reflex arcs and conscious perception.
6. What is the function of motor neurons?
The main function of motor neurons is to transmit impulses from the central nervous system to effectors to produce movement or secretion.
- They stimulate muscle contraction for movement.
- They regulate gland activity such as hormone or enzyme secretion.
- They are essential for both voluntary and involuntary actions.
7. Where are sensory and motor neurons located?
Sensory neurons are located between sensory receptors and the CNS, while motor neurons extend from the CNS to muscles or glands.
- Sensory neuron cell bodies: Found in the dorsal root ganglia of the spinal cord.
- Motor neuron cell bodies: Found in the spinal cord’s ventral horn or brainstem.
- Their axons form part of peripheral nerves.
8. What is the structure of sensory and motor neurons?
Sensory and motor neurons differ in structure mainly in the arrangement of their processes.
- Sensory neurons: Often unipolar (pseudounipolar) with one long dendrite and a short axon.
- Motor neurons: Typically multipolar with many dendrites and one long axon.
- Both contain a cell body (soma), dendrites, and an axon.
9. What is an example of sensory and motor neurons in a reflex action?
In a reflex action like withdrawing your hand from a hot object, sensory and motor neurons form a reflex arc.
- Sensory neuron: Detects heat and sends an impulse to the spinal cord.
- Interneuron: Processes the signal in the spinal cord.
- Motor neuron: Sends an impulse to arm muscles to contract and pull the hand away.
10. Are sensory neurons afferent and motor neurons efferent?
Yes, sensory neurons are called afferent neurons and motor neurons are called efferent neurons based on the direction of impulse transmission.
- Afferent (sensory): Carry impulses toward the CNS.
- Efferent (motor): Carry impulses away from the CNS to effectors.
- This directional terminology helps distinguish their roles in the nervous system.
