Uni-polar neurons, also known as unipolar neurons, have a single process that extends from the cell body, which then branches into two parts: one functioning as a dendrite and the other as an axon. In contrast, bipolar neurons possess two distinct processes: one dendrite and one axon, which are both attached to the cell body. Uni-polar neurons are primarily found in sensory pathways, while bipolar neurons are typically involved in sensory functions, such as in the retina of the eye. This structural difference reflects their distinct roles in the nervous system.
bipolar neuron
The location of dendrite and axon: If dendrite and axon emerge from same process, the neuron is unipolar. If dendrite and a single axon emerge from opposite ends of the soma, the neuron is bipolar. If the neuron has more than 2 dendrite it is called multipolar.
The location of dendrite and axon: If dendrite and axon emerge from same process, the neuron is unipolar. If dendrite and a single axon emerge from opposite ends of the soma, the neuron is bipolar. If the neuron has more than 2 dendrite it is called multipolar.
Afferent
Neurons are grouped structurally according to the number of processes extending from their cell body.
Small ones
Neurons with two processes are classified as bipolar neurons.
Bipolar neurons have only one axon and one dendrite with the soma between them. There are probably very few, if any, neurons that contain only a single axon and dendrite. However, the concept is useful because some neurons behave as if they only had a single axon and dendrite. These neurons, called bipolar neurons because their cell body sits in between the axon and dendrite (giving the neuron two "poles"), are abundant in the nervous system. One very important type of bipolar neuron occurs in the retina, and is responsible for how we process light at an early level.
unipolar (pseudounipolar)
The synaptic terminal of a sensory neuron is located either in the dorsal root ganglion (if it is a pseudo-unipolar neuron) or directly in the spinal cord (if it is a bipolar neuron). This is where the sensory neuron connects with other neurons to transmit sensory information to the central nervous system.
Bipolar neuron
The "Tigger zone" in a unipolar neuron is the initial segment of the axon where action potentials are generated. Here, graded potentials from the dendrites accumulate and if they reach a certain threshold, an action potential is triggered.