State the different types of neurons.
Name different types of neurons and give one function of each.
There are three different types of neurons—sensory neuron, motor neuron and association neuron.
Types of Neurons as per their functions.
1) Sensory Neurons – transmits impulses towards CNS from sensory organ through their axons.
2) Motor Neurons – transmits impulses from CNS towards muscles or glands (effector organs)
3) Mixed Neurons – Consists of both afferent and efferent axons. Conducts both incoming sensory information and outgoing muscles commands in the same bundle
Types of Neurons
There are three major types of neurons: sensory neurons, motor neurons, and interneurons. All three have different functions, but the brain needs all of them to communicate effectively with the rest of the body (and vice versa).
Sensory neurons are neurons responsible for converting external stimuli from the environment into corresponding internal stimuli. They are activated by sensory input, and send projections to other elements of the nervous system, ultimately conveying sensory information to the brain or spinal cord. Unlike the motor neurons of the central nervous system (CNS), whose inputs come from other neurons, sensory neurons are activated by physical modalities (such as visible light, sound, heat, physical contact, etc.) or by chemical signals (such as smell and taste).
Most sensory neurons are pseudounipolar, meaning they have an axon that branches into two extensions—one connected to dendrites that receive sensory information and another that transmits this information to the spinal cord.
Motor neurons are neurons located in the central nervous system, and they project their axons outside of the CNS to directly or indirectly control muscles. The interface between a motor neuron and muscle fiber is a specialized synapse called the neuromuscular junction. The structure of motor neurons is multipolar, meaning each cell contains a single axon and multiple dendrites. This is the most common type of neuron.
Interneurons are neither sensory nor motor; rather, they act as the “middle men” that form connections between the other two types. Located in the CNS, they operate locally, meaning their axons connect only with nearby sensory or motor neurons. Interneurons can save time and therefore prevent injury by sending messages to the spinal cord and back instead of all the way to the brain. Like motor neurons, they are multipolar in structure.