The key difference between nerve and neuron is that the nerve is a bundle of axons wrapped in a connective tissue while the neuron is a cell that acts as the basic functional unit of the nervous system.
The animals, unlike plants, have special and well-developed systems to respond to the stimuli of the external environment and create changes within the body. Nervous system coordinates the immediate and necessary changes by the electric signals while the endocrine system mediates the long term chemical changes. The nervous system consists of the central nervous system (CNS) comprising the brain and the spinal cord, and the peripheral nervous system, which is outside the central nervous system. In multicellular animals, sensory cells detect the sensory information and pass them to effector cells after processing and producing a response. Accordingly, neurons and nerve cells carry out this signal transmission from sensory organs to the central nervous system and then to the effector organ. The main purpose of this article is to discuss the difference between nerve and neuron.
CONTENTS
1. Overview and Key Difference
2. What is a Nerve
3. What is a Neuron
4. Similarities Between Nerve and Neuron
5. Side by Side Comparison – Nerve vs Neuron in Tabular Form
6. Summary
What is a Nerve?
The nerve is a bundle of axons or dendrites wrapped in connective tissue that conveys impulses between the central nervous system and some other parts of the body. A typical nerve has a tough outer covering called epineurium. Inside the epineurium, there are long fibrous axons or dendrites of individual neurons, gathered into bundles called fascicles, wrapped in the perineurium. Each axon within these bundles is further wrapped by a myelin sheath formed by Schwann cells, to keep the nervous impulses insulated. Most large nerves are mixed nerves, containing both motor and sensory nerve fibres running to and from a particular region of the body.
Figure 01: Nerve Fibre
Moreover, there are three main types of nerves; afferent nerves (sensory), efferent nerves (motor), and mixed nerves (both sensory and motor). Afferent nerves send the signals from sensory organs to the central nervous system while the efferent nerves send the signals from CNS to effector organs.
Similarly, mixed nerves carryout both receiving and sending information to the CNS. Further nerves can be classified into two types; cranial nerves and spinal nerves. Cranial nerves start from the brainstem, and they are responsible for sensing information to the brain. On the other hand, spinal nerves connect the spinal column and spinal cord.
What is a Neuron?
Neurons are the conductive cells of the nervous system and interpose between the receptors and effectors. They are the basic structural and functional units of the nervous system and ramify throughout an organism, forming an elaborate communication network. A neuron has three components such as a cell body, dendrites and an axon.
Figure 02: Neuron
Moreover, there are three basic types of neurons such as pseudounipolar neurons (perform a sensory function), bipolar nerve cells (situated within the CNS, and transfers the signals either to a motor neuron or to the brain), and the multipolar neuron (is a motor neuron associated in transmitting a response signal on to a muscle or within the CNS).
What are the Similarities Between Nerve and Neuron?
- Nerve and neuron are components of the nervous system.
- They transmit electrical impulses of the nervous system.
- They are extremely important elements of an organism concerning the signal perception and responding.
- Nerves are projections of neurons.
- The myelin sheath is in both nerves and neurons.
- Any physical damage to the nerves or the neurons can cause pain, loss of sensation, or loss of muscle control.
What is the Difference Between Nerve and Neuron?
A nerve is necessarily a collection of axon bundles in the peripheral nervous system. It consists of many axons wrapped in three layers of connective tissues for protection and insulation. On the other hand, a neuron is an individual cell of the nervous system and has only one axon; it may be branched and extend in more than one direction. Hence, the key difference between nerve and neuron is that the neurons are single nerve cells whereas the nerves are elongated congregations of tissues.
Furthermore, we can identify a difference between nerve and neuron based on location; neurons are in the central and the peripheral nervous systems, but the nerves are only in the peripheral nervous system. Moreover, the neurons are grouped according to the number of extensions that extend from the neuron’s cell body and by the direction that they send information. But the nerves are grouped by the place of their origin in the central nervous system or their destination. Therefore, we can consider this as another difference between nerve and neuron. A further difference between nerve and neuron is in their function. It is the single neuron that transmits the action potential of a stimulus or the replying motor signal along the axons dendrites and the cell body whereas, the nerves simply covey the axons to and from the CNS.
In addition, there are three basic types of nerves such as afferent nerves, efferent nerves and mixed nerves. On the other hand, sensory neurons, motor neurons and interneurons are the three types of neurons.
Below is infographic on the difference between nerve and neuron.
Summary – Nerve vs Neuron
Nerve and neuron are two components of the nervous system. The nerve is a structure consisting of a bundle of axons surrounded by connective tissue. On the other hand, a neuron is an individual cell which is the basic functional unit of the nervous system. Nerves are present in the peripheral nervous system while the neurons are present in both the CNS and peripheral nervous system. Furthermore, a nerve consists of many axons while a neuron has only one axon. Three types of nerves are afferent, efferent and mixed nerves while the three types of neurons are sensory, motor and interneurons. Thus, this summarizes the difference between nerve and neuron.
Reference:
1. “Neuron.” Wikipedia, Wikimedia Foundation, 5 Jan. 2019. Available here
2. “Nerve.” Wikipedia, Wikimedia Foundation, 15 Dec. 2018. Available here
Image Courtesy:
1.”1319 Nerve StructureN” By OpenStax College – Anatomy & Physiology, Connexions Web site. Jun 19, 2013., (CC BY 3.0) via Commons Wikimedia
2.”Blausen 0657 MultipolarNeuron”By BruceBlaus – Own work, (CC BY 3.0) via Commons Wikimedia